N FRANCISCO 
 
 STATE OF CALIFORNIA 
 
 EARL WARREN. Governor 
 
 DEPARTMENT OF NATURAL RESOURCES 
 
 WARREN T. HANNUM, Director 
 
 DIVISION OF MINES 
 
 FERRY BUILDING, SAN FRANCISCO 11 
 
 OLAF P. JENKINS, Chief 
 
 SPECIAL REPORT 32 
 
 JULY 1953 
 
 GEOLOGICAL INVESTIGATIONS OF 
 STRONTIUM DEPOSITS 
 
 IN SOUTHERN CALIFORNIA 
 
 By CORDELL DURRELL 
 United States Geological Survey 
 
Digitized by the Internet Archive 
 
 in 2012 with funding from 
 
 University of California, Davis Libraries 
 
 http://archive.org/details/geologicalinvest32durr 
 
CONTENTS 
 
 Page 
 
 Celestite deposits near Ocotillo, San Diego County, California 5 
 
 Celestite deposits at Bristol Dry Lake, near Amboy, San Bernardino County, 
 California 9 
 
 Celestite deposits near the southern end of Death Valley, San Bernardino 
 County, California 15 
 
 The Solomon and Boss strontianite deposits, Mud Hills, San Bernardino 
 County, California 23 
 
 Celestite deposits near Ludlow, San Bernardino County, California 37 
 
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CELESTITE DEPOSITS NEAR OCOTILLO SAN DIEGO COUNTY, CALIFORNIA* 
 
 By Cordell Durrell ' 
 
 OUTLINE OF REPORT 
 
 Page 
 ;ract 5 
 
 oduction 5 
 
 logy 5 
 
 ■rence 7 
 
 Illustrations 
 ire 1. Map showing locations of strontium deposits in South- 
 ern California 4 
 
 2. Map showing location of celestite deposit near Oco- 
 tillo, San Diego County, California 5 
 
 3. Geologic map of the celestite deposit near Ocotillo, 
 San Diego County, California 6 
 
 ABSTRACT 
 
 •lestite rock is associated with bedded gypsum in Tertiary sedi- 
 ary rocks about 9$ miles south of Ocotillo, San Diego County, 
 lornia. The celestite is a cap 2 to 8 feet thick on the top of 
 •al small hills. A part of the celestite has been mined. 
 
 INTRODUCTION 
 
 elestite occurs in the south end of a small range of 
 about 9^ miles south of Ocotillo, California, a few 
 fired yards west of the road from Ocotillo to the gyp- 
 quarries on Fish Creek Wash, and just north of Fish 
 l;k Wash. The deposit is almost on the boundary be- 
 Isn San Diego and Imperial Counties, at an elevation 
 i-een 500 and 600 feet (fig. 2). The region is extremely 
 ■ 
 
 le area has been described previously only by Moore 
 •wett et al., 1936, p. 154) , but his report was not accom- 
 i ed by a map. The Pan-Chemical Company, of Clare- 
 ( t, California, owns the deposit, 
 ie field work for this paper was done in 1947 by the 
 I . Geological Survey, in order to complete the study 
 J n during World War II on the strontium deposits in 
 a ■ ornia. 
 
 GEOLOGY 
 
 ratigraphy. The celestite rock caps several small 
 1 . and overlies sedimentary rocks of probably Middle 
 • pper Tertiary age. The oldest exposed rock of the 
 'i is sedimentary breccia that comprises the lower 
 i:s of the hills on which the celestite lies. The breccia 
 
 mposed predominantly of a gray granitic rock, but 
 I :s of pegmatite, schist, gneiss, and quartzite are pres- 
 it Although the section exposed shows no bedding, the 
 I nentary origin is certain, for some well-rounded 
 1 lers are present. A sandy matrix can be seen in a few 
 I cuts, but it is not evident on the eroded hill-slopes. 
 t ekness of about 165 feet of breccia is exposed near the 
 1 sit. 
 
 '. e breccia is overlain by gypsum, but there is a transi- 
 ts 1 zone about 10 feet thick between the two in which 
 ie are alternations of sand, sandy silt, and argillaceous 
 I im, with the gypsum increasing toward the top. The 
 I] un is thinly bedded and dark colored, with impuri- 
 " car the base. It is more massive and lighter colored 
 I >, except for a gray to black zone 20 to 30 feet above 
 ie ase that contains powdery manganese oxides. 
 
 ' 1 ilication authorized by the Director, U. S. Geological Survey, 
 [anuscript submitted for publication January 1953. 
 I logist, U. S. Geological Survey. 
 
 The upper part of the gypsum has a fine columnar 
 structure, with the columns apparently normal to the 
 bedding planes. Toward the top, the gypsum is cavernous 
 owing to solution in weathering, which has permitted 
 considerable gravity collapse near the hilltops. 
 
 The highest points in the area are capped by celestite 
 rock. Evidently the celestite occurred as lenses in the 
 gypsum and now is present only as erosion remnants. 
 The interval between the base of the gypsum and the base 
 of the celestite is about 90 feet on the west hill and 150 feet 
 on the east hill ; hence the celestite cannot all be at the 
 same stratigraphic horizon. 
 
 t^Io_Sano 
 
 ego ^ 
 
 Ocoti llo' 
 
 BENSONS DRY LAKE 
 
 F-===JS 111 
 
 IN 
 
 [-170... 
 
 up 
 
 52 
 
 1 
 
 
 
 
 1 
 
 "*"■> ^HALFHILt\ DRY LAKE 
 
 
 
 T ! 
 
 
 
 j — J 
 
 •i 
 
 
 1! 
 
 CELESTITE DEPOSIT \^ f>'" 
 
 
 O 1 
 
 i i 
 
 z 
 
 i 
 
 3-.LES J\ \ GYPSUM QUARRY 
 
 / i 
 
 Figure 2. Map showing location of celestite deposit near Ocotillo, 
 San Diego County, California. 
 
 Structure. The beds dip gently to the east in the west- 
 ern part of the area and a little more steeply in the same 
 direction in the eastern part. Attitudes cannot be reliably 
 determined, owing to slumping on the steep slopes, but 
 the maximum dip is about 15°. 
 
 Many small faults are visible in the outcrop but only 
 three were mapped. Two of these probably have displace- 
 ments of only a few feet. The largest of the three strikes 
 in a northerly direction through the deposit and dips west. 
 The beds on the west are downthrown about 18 feet on 
 the north side of the hill and about 40 feet on the south 
 side of the hill. 
 
 (5) 
 
Special Report 32 
 
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Strontium Deposits, Southern California 
 
 Character of the Celestite. The celestite is resistant to 
 
 ■ athering and forms a cliff at its margin. It is bent down 
 i the edges of the hill owing to collapse of the gypsum 
 ueath. In places a breccia of angular blocks of celestite 
 :1 gypsum 2 to 5 feet thick that no doubt formed by the 
 lapse of cavernous gypsum lies below the celestite lenses. 
 The celestite is very white on fresh surfaces but 
 nthers to a dull reddish brown. Some of it is massive, 
 
 ; much is porous, with needlelike crystals lining the 
 . ities. Much of it is marblelike in appearance, but a con- 
 jrable amount has a columnar structure that probably 
 
 ■ iseudomorphous after the columnar gypsum. 
 
 'he following analysis is of a representative sample 
 i.ected by Moore (Hewett et al., 1936, p. 161). 
 
 Analysis of celestite rock* 
 
 Percent 
 0.90 
 0.49 
 0.50 
 2.47 
 0.05 
 
 SiO a 
 
 A1 2 3 
 
 Fe 2 3 
 
 CaO 
 
 MgO 
 
 SrO 52.88 
 
 BaO 1.53 
 
 MnO Trace 
 
 SOs 41.44 
 
 C0 2 0.71 
 
 H.0 0.16 
 
 Analyst, Charles Milton. 
 
 101.13 
 
 The celestite ranges in thickness between 2 and 8 feet 
 and averages about 5 feet. 
 
 REFERENCE 
 
 Hewett, D. F., Moore, B. M., Callaghan, E., Nolan, T. B., Rubey, 
 W. W., and Schaller, W. T. (1936), Mineral resources of the 
 region around Boulder Dam: U. S. Geol. Survey Bull. 871, 
 197 pp. 
 
CELESTITE DEPOSITS AT BRISTOL DRY LAKE, NEAR AMBOY 
 SAN BERNARDINO COUNTY, CALIFORNIA* 
 
 By Cordell Durrell 
 
 OUTLINE OF REPORT 
 
 hstract 
 
 Page 
 9 
 
 itroduction q 
 
 leneral geology q 
 
 escription of the celestite concretions,. " 12 
 
 Iieniical composition of the celestite ~ 12 
 
 rigin of the celestite 13 
 
 eferences ~ -.a 
 
 Illustrations 
 igure 4. Map showing location of celestite deposits at Bristol 
 Dry Lake, near Amboy, San Bernardino Countv, Cali- 
 fornia 
 
 9 
 
 5. Section of the test pit 10 
 
 11 
 
 Geologic map of celestite deposit at Bristol Dry Lake, 
 near Amboy, San Bernardino, California 
 
 ABSTRACT 
 
 Concretions of celestite have been found along the south margin 
 Bristol Dry Lake for a distance of 3 miles, both east and west of 
 e county road from Amboy to Twentynine Palms. So far as known 
 ey are most abundant in sec. 6, T. 4 N., R. 12 E., S.B., where they 
 >re exposed by plowing. A test pit 3 feet deep showed concretions 
 three horizons to a depth of 1.6 feet. 
 
 The very rough, irregular concretions are in sandy gypsiferous clay 
 d in thin-bedded sand. They probably replaced the sediment in 
 nch they are found. Strontium is present in the sediment below 
 i concretions and in the waters of the playa. This fact and the 
 ■ucture of the concretions suggest that the concretions are forming 
 present. 
 
 INTRODUCTION 
 
 Bristol Dry Lake is a large playa in southern San 
 ■rnardino County, California, a short distance south of 
 e town of Amboy, which is 85 miles east of Barstow and 
 miles west of Needles, on U. S. Highway 66 and on the 
 ;chison, Topeka & Santa Fe Railway. The dry lake, 
 hch is about 6 miles wide and 10 miles long, is at an 
 :itude of 600 feet. The celestite deposit is near the south 
 ge of the lake 6 miles south of Amboy, in the Si sec. 6, 
 4 N., R. 12 E., S.B., and 1 mile west of the countv road 
 >m Amboy to Twentynine Palms (fig. 4) . 
 
 AMBOY 
 
 •% 
 
 CELESTITE/tS% 
 DEPOSIT « 
 
 Twentynine Palms 
 
 1URE 4. Map showing location of celestite deposits at Bristol 
 Dry L ake, near Amboy, San Bernardino County, California. 
 
 ublication authorized by the Director, U. S. Geological Survey 
 Manuscript submitted for publication January 1953. 
 
 2—74750 
 
 The work on which this report is based was apparently 
 the first geological study to be made of the deposit, and 
 was undertaken as a part of the World War II program 
 of the investigation of strategic minerals by the U S 
 Geological Survey. The only previous notice concerning 
 the deposit is in a California state report on the mineral 
 resources of San Bernardino County (Tucker and Samp- 
 son. 1943, p. 544). 1 
 
 Concretions of celestite are present on the surface of 
 the playa at several places east of the deposit, and a few 
 are reported to have been found near Amboy. The presence 
 of celestite has apparently been known locally for some 
 time through the finding of occasional concretions The 
 deposit is on public land held by the National Chloride 
 Company as mineral claims. Celestite did not show at the 
 surface, but was discovered accidentally in 1941 by M. M. 
 Stephens, who was in charge of field operations for the 
 company, while grading a road near the south edge of the 
 playa. 
 
 The present work was greatly aided by the courtesy 
 of Frank Thomas and M. M. Stephens of the Desert Prop- 
 erties Company, former owners of the deposit. A. Cowles 
 Daley assisted the writer in the field and in the prepara- 
 tion of the geologic map. 
 
 GENERAL GEOLOGY 
 
 Almost nothing is known about the geology of the 
 country surrounding Bristol Dry Lake ; there are no ade- 
 quate maps of the region, and the writer has only a 
 meager knowledge of the part of the area adjacent to "the 
 lake. The playa is surrounded by broad areas of alluvial 
 fans bordered by high, rugged mountains. The mountains 
 on the west and northwest are of Tertiary volcanic rock 
 and older intrusive igneous rocks. Basalt and andesite and 
 their tuffs are probably dominant among the volcanics, 
 but rhyolite tuff is also present. The older rocks are quartz 
 monzonite and granite. Granitic rocks occur south of the 
 lake also. It is probable that a wide variety of rocks, in- 
 cluding sedimentary and metamorphic rocks as well as 
 igneous rocks, is present in the basin. Adjoining the lake 
 on the west and partly buried beneath the surface layers 
 of clay is a large body of olivine basalt of recent age that 
 occupies a roughly circular area 6 to 8 miles in diameter 
 centered on a large cinder cone. The flow is probably 
 several hundred feet thick near the vent. The age of the 
 basalt is not known exactly, but it is prehistoric and is 
 probably not earlier than late Pleistocene. 
 
 The surface of the playa is composed of powdery 
 yellowish-brown silty clay that gives wav abruptly to 
 gravel at the margin of the playa. Windblown sand is 
 present here and there near the edge of the playa and on 
 the gravel south of the celestite deposit. 
 
 The central part of the lake contains a large body of 
 halite. According to Moore (Hewett et al., 1936, p. 94) 
 the top of the salt is 5 feet below the surface of the piaya ; 
 the salt body is 5 feet thick where it is being mined, and 
 it underlies 5,000 acres. The salt beds range from an inch 
 to a foot in thickness, and are separated by thin layers of 
 clay. The salt body is porous and contains an interstitial 
 brine rich in calcium chloride. Several companies produce 
 salt and two produce calcium chloride from this deposit. 
 
 (9) 
 
10 
 
 Special Report 32 
 
 Feet 
 
 Surface of Playa 
 
 3 1 - 
 
 
 m iirnrnf" 1 ^ 1 iwiiii!m»'..irni -=" SuuriTiMii ■ 
 
 j^ifailwlrtMitlV\WWWwtaW^UMV\\*yf.lU|lMWUi£ 
 
 
 interval 
 
 0.0-0.3 Soft yellowish gray silt with surface crust cemented by halite. 
 
 0.3-0.6 Porous yellow-brown sandy clay with gypsum crystals up to 3 inches 
 in length. Scattered small celestite nodules. 
 
 06-1.1 Celestite nodules in coarse-bladed gypsum with yellow-brown clay 
 motnx at the top becoming sandy toward the base. Half -inch 
 crust of gypsum ai the base. 
 
 I.I - 1.3 Medium-grained porous gypsum with yellow clay matrix. 
 
 13-1.6 Fme g.ay to yellow silty sand containing a few nodules of celestite. 
 Quarter-inch gypsum crust at the base. 
 
 1.6-1.9 Fme yellow clayey sand and sandy clay. 
 
 1.9-2.0 Yellow sandy clay with crust of gypsum crystals at the base. 
 
 2.0-2.3 Thin-bedded clayey gray, brown, and reddish fine sand. 
 
 2.3-2.8 Brownish sandy clay at top grading downward into brown clay with 
 costs of halite crystals and irregulor small cavities. 
 
 2.8-2.9 Medium-grained cleon groy sand with half-inch gypsum crystals at top. 
 2.9-30 Yellow silty cloy. 
 
 Figure 5. Section of the test pit. 
 
 The clays above the salt body are hygroscopic, probably 
 because they contain calcium chloride, and the color of 
 the moist clay outlines the salt body. The salt body evi- 
 dently does not extend as far south as the celestite de- 
 posit. 
 
 Concretions of celestite are present on the surface ot 
 the playa near its south edge and beside the county road 
 that traverses the dry lake ; and many more are present 
 in the first few inches of the clay. Those on the surface 
 have been exposed by deflation. Concretions also occur 
 sporadically on the surface for 2 miles east of the county 
 road along the south edge of the playa. The deposit of 
 the National Chloride Company is a mile west of the 
 countv road and about 750 feet from the margin of the 
 playa; but concretions were not present on the surface 
 there. Celestite is thus known to be present here and there 
 for a distance of 3 miles along the south side of the playa. 
 It has also been reported near the north edge, near Amboy. 
 Exploration might show it to be present all around the 
 
 plava. 
 
 After celestite was discovered on the holdings ot the 
 National Chloride Company, an attempt was made in 
 1942 to develop the ground and determine the extent of 
 the deposit. Furrows were plowed at intervals of about 
 10 feet with a heavy plow that penetrated about a foot. 
 Some of the celestite uncovered in this manner was stacked 
 in the field and two carloads were shipped in 1942. The 
 area has remained idle since then, although several car- 
 loads of concretions remain on the ground. 
 
 The deposit was fairly well outlined by the plowing, 
 and the ground so explored is shown on figure 6,as is the 
 area of greatest concentration of concretions. Scattered 
 concretions are known outside the last line, and the limits 
 of the celestite deposit are not yet known. Celestite is not 
 present in the two pits south of the deposit ; only a little is 
 visible in the well at the east end, and none is exposed in 
 the furrows at the extreme west end of the deposit. The 
 northern limit of the deposit is undetermined. 
 
 In order to examine the occurrence of the concretio. 
 in detail, and to obtain information on the amount 
 celestite present, a test pit 3 feet square and 3 feet de 
 was dug near the center of the deposit in ground that h, 
 not been previously disturbed. The section of the roc; 
 exposed in the test pit is shown in figure 5. 
 
 The first celestite was encountered between 0.3 and G 
 of a foot below the surface. The largest concretion the' 
 was only about 2 inches long and the total weight of cek 
 tite recovered from the layer was only 12 ounces. The ec 
 cretions were the same in all respects as those in the zoi 
 below. 
 
 Most of the celestite— 159 pounds of the total of l) 
 pounds recovered from the pit — was between 0.6 of a f(t 
 and 1.1 feet below the surface. The top of this zone l 
 marked by a well-defined bedding plane. Above it is san J 
 gypsiferous clay that contains the uppermost collec- 
 tions ; below it is yellow-brown clay with nearly vertnl 
 blades of gypsum 3 to 6 inches long. The clay contaim: 
 the abundant celestite nodules becomes sandy at abet 
 0.3 of a foot below the top of the bed, and the base> 
 marked by a half-inch layer of porous gypsum with bla<s 
 arranged nearly vertically. 
 
 The celestite concretions are closely spaced near tja 
 bottom of the sandy portion of the bed, but none of th i 
 penetrates the gypsum below. Most of the small cone - 
 tions were in the sandy portion of the bed ; the larger ois 
 extended from near the base of the bed through the sanj 
 part into the gypsiferous clay above. Apparently the 1o\t 
 limit of the concretions was controlled by the gypsum t 
 the base ; the concretions started to form in the sandy ztfi 
 above the gypsum, and the upper limit of growth jj 
 fixed bv the top of the bed. Only a few concretions grv 
 large enough to extend to the top of the bed. The conc- 
 tions range in diameter from a quarter of an inch to m<e 
 than a foot. 
 
Strontium Deposits, Southern California 
 
 11 
 
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 H1U0N 30«J 
 
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12 
 
 Special Report 32 
 
 Bladed gypsum with a yellow clay matrix underlies the 
 half -inch-thick layer of porous gypsum at the base of the 
 concretion-bearing beds. Underneath this, from 1.3 to 1.6 
 feet below the surface of the playa, is a layer of thin- 
 bedded, fine, gray to yellow silty sand that also contains 
 celestite concretions. This layer is much sandier than the 
 two higher celestite-bearing zones, but the concretions are 
 not very numerous. Only 9 pounds 4 ounces of celestite 
 was recovered from it. The concretions are simple in out- 
 line, and the largest was only about 8 inches long. 
 
 The beds below the lowest celestite-bearing stratum con- 
 sist of fine sand, sandy clay, and clay with two thin beds 
 of gypsum. The clay from about 2.3 to 2.8 feet beneath 
 the surface contains abundant casts of halite crystals as 
 much as a quarter of an inch on an edge, and many irregu- 
 lar cavities as well. Many of the cavities are lined with 
 a black film of manganese oxide. 
 
 All the sediments were moist with brine on April 24, 
 1945, when the pit was dug. The clay with casts of halite 
 crystals and the lower beds were saturated with a strong 
 brine, and brine oozed into the bottom of the pit. On the 
 same day the water level in the well 800 feet east of the 
 test pit was 5 feet below the surface. 
 
 The sediments exposed to a depth of 3.5 feet below the 
 surface at the well are essentially the same as those in the 
 test pit, and a few small celestite concretions are present 
 in yellow clay with bladed gypsum from 1.0 foot to 1.2 
 feet below the surface. 
 
 Perhaps celestite concretions are present at greater 
 depth in the playa sediments, but no information is avail- 
 able concerning the beds deeper than 3.5 feet. 
 
 DESCRIPTION OF THE CELESTITE CONCRETIONS 
 
 The smaller concretions are fairly regular in outline. 
 The larger concretions are knobby and closely resemble 
 potatoes in size and shape. Still larger concretions are 
 much more irregular and were evidently formed by the 
 coalescence of adjacent concretions. They have the form 
 of irregular chains and rings and complex forms that 
 defy description. The junctions are usually weak, so 
 that the component parts break apart readily, and for 
 that reason it is not possible to give the maximum size that 
 is reached by a continuous body of celestite. The largest 
 dimension of the simpler concretions is generally not more 
 than 6 inches. This may be taken as a rough expression of 
 the maximum spacing of the centers about which the 
 concretions started to form. 
 
 Most concretions are composed of dense creamy white 
 celestite in thick basal tablets that range in maximum di- 
 mension from 0.02 to 0.08 mm, and contain a trace of 
 gypsum in minute grains. 
 
 "Cracks about a quarter of an inch deep that bound 
 polygonal areas from a quarter to half an inch wide are 
 present on the lower surfaces of most of the concretions. 
 The celestite of the polygons is soft, and some of it has 
 a mushy consistency. Unindurated celestite also is pres- 
 ent on the tips of knobs, and at the connecting links be- 
 tween the larger portions of the complex concretions. 
 
 The margin of the concretions, a zone from 0.5 to 5 mm 
 thick, is finer grained ; the grain size ranges from 0.01 to 
 03 mm. The marginal part also contains a little gypsum, 
 small rhombs of a carbonate— probably calcite— and 
 clastic grains, among which quartz, plagioclase, horn- 
 blende, augite, microcline, and partly glassy andesitic 
 
 or basaltic rock fragments were identified. In most con 
 cretions the clastic grains are confined to the fine-grainec 
 margin. The clastic grains are most numerous and bes- 
 rounded at the surface of the concretions, and are les: 
 numerous, smaller, and less well rounded progressively 
 inward. The surfaces of the grains inward from the sur 
 face of the concretion are pitted as though attacked b 
 solution. By the growth of such solution pits the grain 
 become smaller, are divided into several parts, are re 
 duced to shreds, flakes, and angular fragments, an< 
 finally disappear. 
 
 No large gypsum crystals have been found enclose* 
 within the concretions, although some external gypsur 
 crystals are partly embedded in celestite. The embedded 
 parts are reduced in size and have irregular, pitted sui 
 faces as though they had undergone solution. _ 
 
 Nearly all the concretions contain cavities, some o 
 which are lined with small crystals of celestite. Some o 
 the cavities, particularly the smaller ones, are very ij 
 regular in form, but most are shaped like a double conve 
 lens. Some of the lens-shaped cavities are very small, bv 
 others have a maximum diameter of 2 to 3 inches. A fe- 
 were found that passed nearly through the concretion 
 
 The concretions of the lower zone are essentially tb 
 same as those in the first and secend zones. They wei 
 formed, however, in thin-bedded silty sand, and tl 
 bedding planes show on the surfaces of the concretions ; 
 irregularities. The bedding planes are not evident in tl 
 interiors of the concretions. 
 
 The concretions present at other places east of this d 
 posit are identical with those found here, and they als 
 are in gypsif erous sandy clay at a depth of about a foo 
 CHEMICAL COMPOSITION OF THE CELESTITE 
 
 Although it was evident from the hand-specimen ai 
 microscopic examinations that the concretions are almo 
 pure celestite, the following analysis of celestite from tl 
 zone of most abundant concretions, exposed in the te 
 pit, was made for confirmation. 
 
 Anaylsis of celestite concretions * 
 
 Si0 2 
 
 A1 2 3 
 
 FeaOs 
 
 MgO 
 
 CaO 
 
 Na=0 
 
 CO* 
 
 SO3 
 
 CI 
 
 MnO 
 
 BaO 
 
 SrO 
 
 Organic carbon _ Prese nt 
 
 99.17 
 
 Less 0=C1 
 
 Total 
 
 Percent 
 
 . 1.06 
 
 . 0.21 
 
 . 0.13 
 
 . (a) 
 
 . 1.58 
 
 . 0.45 
 
 - (a) 
 _ 42.40 
 _ 0.54 
 
 - (a) 
 
 - (a) 
 . 52.80 
 
 99.05 
 
 ^Analysir^rG.'FaTrchnd. Sample from depth of 0.6 of a foot to 1.1 tetta»j 
 in SW1 sec. 6. T. 4 N., R. 12 E., S. B., Bristol Dry Lake, San Bernardino Con. 
 California. 
 
 When recalculated the above analysis gives the ft 
 lowing : 
 
 NaCl J88 
 
 SrSO* — - -- 9 |g 
 
 CaSO, 2.86 
 
 Clastic grains, etc loi ^ 
 
 Total 9 9 - 05 
 
A partial analysis of the silty clay in the test pit below 
 [i celestite shows some strontium to be present there also. 
 
 Strontium Deposits, Southern California 
 
 13 
 
 CaO 
 BaO 
 SrO 
 
 CI __ 
 
 C0 2 
 
 S0 3 - 
 
 Pariial analysis of silty clay * 
 
 7.00 
 (a) 
 0.03 
 1.05 
 1.48 
 6.3S 
 
 Less than 0.01 percent. 
 
 1 lalysis by J. B. Fairchild. Sample from depth of 2.3 to 2.8 feet in test pit in SWJ 
 I sec. 6, T. 4 N., K. 12 E., S. B., Bristol Dry Lake, San Bernardino County, California. 
 
 This analysis is recalculated as follows, and the con- 
 jtuents so calculated were separately confirmed as 
 
 : ; isent : 
 
 Na.SO-4 4.62 
 
 NaCl 3.22 
 
 CaSO* 12 74 
 
 CaCOs 3.36 
 
 SrSO* 0.05 
 
 The sample contained casts of halite crystals, films of 
 ick manganese oxide, small soft concretions of CaC0 3 , 
 1 crystals of gypsum. The analysis indicates the pres- 
 >e of strontium sulfate in small amounts in the sedi- 
 pts surrounding the concretions. 
 
 In order to determine whether or not strontium was 
 : terally present in Bristol Dry Lake, two samples of wa- 
 1 were analyzed. 
 
 Analysis of waters from Bristol Dry Lake 
 in parts per million* 
 
 I II 
 
 17,190 43,300 
 
 598 1,074 
 
 393 962 
 
 46,070 57,370 
 
 1,479 3,303 
 
 104,600 172,900 
 
 Ca 
 
 Mg 
 
 Sr 
 
 Na 
 
 K 
 
 CI 
 
 SO* 1,048 
 
 B4O7 88 
 
 210 
 30 
 
 Jyses by W. W. Brannock. Sample I from shallow well in SEJ sec. 6, T. 4 N., R 12 
 !., S. B., within the area containing celestite concretions. Sample II from drainage 
 anal in salt body of Bristol Dry Lake at mill of National Chloride Company, 6 miles 
 outh of Amboy. 
 
 'hese anaylses indicate that strontium is probably 
 sent in solution in the water contained in the sedi- 
 1 its throughout the playa. 
 
 ORIGIN OF THE CELESTITE 
 
 h is clear that the celestite concretions form by pre- 
 
 tation of strontium sulfate from the strontiuni-bear- 
 1 waters of the playa, and that they form within the 
 W of sediment. The growth of the concretions has re- 
 led in the disappearance of the gypsum and clastic 
 ; ment that formerly occupied the space. There is no 
 iirtion of the thin-bedded sand around the concre- 
 1 9 of the lower zone, as would be expected were the 
 jrth of the concretions accomplished by pushing aside 
 ii slastic material. The course of replacement of clastic 
 ■ trials by celestite can be traced by the gradual disap- 
 (•ance inward of the clastic grains enclosed in the 
 I ?ins of the concretions. 
 
 ie structure of the concretions indicates that the celes- 
 • precipitated at the margins of the concretions as a 
 
 grained mush that then recrystallized to a coarser 
 ' a size, became more compact, and shrank as the con- 
 
 ^d clastic grains dissolved. The polygonal cracks and 
 
 internal openings lined with crystals are evidence of such 
 shrinkage. 
 
 The features mentioned above likewise indicate that 
 the concretions are being formed at the present time. The 
 polygonally cracked mushy celestite is obviously the re- 
 cently deposited material that has not yet become thor- 
 oughly recrystallized. It is to be expected, of course, that 
 deposition of celestite, as well as gypsum and halite, is 
 taking place now, because the brine contains strontium 
 and the basin is a site of evaporation. Were the reverse 
 true — that the strontium in the brine comes from the solu- 
 tion of concretions — the concretions should lack the mushy 
 outer zones, and should also lack the thin margin that 
 contains partly dissolved clastic grains. 
 
 The immediate cause of deposition of strontium sulfate 
 is doubtless the evaporation of water from the suface of 
 the marginal part of the playa, which causes the residual 
 brine to become saturated with that substance. Since the 
 amount of evaporation varies with the season as does the 
 accession of water to the lake clays, the celestite is proba- 
 bly deposited intermittently. 
 
 Neither detailed geological study nor chemical analysis 
 is likely to shed much light on the initial source of the 
 strontium until a great deal of information on the geology 
 of the basin as a whole and on the subsurface conditions of 
 the playa becomes available. Several possible sources of 
 the strontium that merit some discussion can, however, 
 be postulated. The strontium may have been derived by 
 weathering from the rocks of the drainage basin, and then 
 concentrated in the waters of the playa by evaporation ; 
 it may have been carried into the playa as a dispersed con- 
 stituent of pyroclastic rocks or lava flows and then re- 
 leased in soluble form by alteration; or, it may have 
 come from an original igneous source and have reached the 
 surface somewhere in the drainage basin or the playa 
 through solfataric activity or spring waters partly of 
 juvenile origin. 
 
 The strontium content of most rocks is very small ; yet, 
 since little is known about the rocks of the basin surround- 
 ing Bristol Dry Lake, the possibility that the strontium 
 could have been derived by general weathering followed 
 by concentration through evaporation cannot be ruled 
 out. Perhaps, under this view, the Tertiary tuffs and flows 
 are the most likely sources, for deposits of celestite and 
 strontianite of Tertiary age are present elsewhere in the 
 Mojave Desert region in close association with similar 
 volcanic rocks. There is no information, however, on the 
 strontium content of the Tertiary volcanic rocks either in 
 the Bristol Lake basin or in adjacent regions. The olivine 
 basalts west of the playa cannot have been the source for 
 they are so recent as to be scarcely weathered. 
 
 It may be postulated as a special case that the strontium 
 was derived by weathering of an older deposit of strontium 
 minerals. The largest known nearby strontium deposit of 
 Tertiary age is the celestite body near Ludlow, 35 miles 
 west of Bristol Dry Lake. Perhaps similar deposits are 
 present in the Bristol Lake basin buried beneath the ex- 
 tensive alluvial fans. The celestite deposit near Ludlow 
 cannot have been the source, for, although the two areas 
 were separated by only a single drainage divide until the 
 recent eruption of the olivine basalt, the region is ex- 
 tremely arid, and the basins were probably never con- 
 nected by either surface or subsurface drainage. 
 
14 
 
 Special Report 32 
 
 Little can be said about the second possibility for noth- 
 ing is known about the sediments of the playa beyond a 
 depth of 5 feet. The olivine basalt flows west of the lake 
 are partly buried by the uppermost sediments of the 
 playa, but the extent to which they underlie the playa is 
 not known nor are there any data concerning the stron- 
 tium content of the lava. It is possible that the strontium 
 ivas derived from the basalt either by its liberation in the 
 volatile constituents given off as the lava solidified or by 
 alteration of the lava subsequent to burial by the sedi- 
 ments of the playa. 
 
 The third possibility, involving the concentration of 
 rare elements by means of, or in association with, igneous 
 processes, is at least as acceptable and perhaps more ac- 
 ceptable than concentration by epigene processes. If 
 strontium was concentrated in a hydrothermal solution 
 in the same manner as hypogene ore-forming solutions in 
 general, it could have been brought to the surface any- 
 where in the drainage basin through solfataras or spring 
 water partly of juvenile origin and then carried into the 
 
 playa by meteoric waters, or it could have been introduced 
 directly into the wet sediments of the playa from below. 
 Once the strontium was in solution in the brine it could 
 have been deposited in the celestite nodules under the 
 control of processes ordinarily called sedimentary. It 
 would be affected by the ground-water regime and by the 
 character and disposition of the chemical and clastic 
 sediments. Such an origin involves a combination of 
 hydrothermal and sedimentary processes, with the lattei 
 process, which is also the last to operate, controlling the 
 final position and character of the deposit. 
 
 REFERENCES 
 
 Hewett, D. F., Moore, B. N., Callaghan, Eugene, Nolan, T. B. 
 
 Rubey, W. W., and Schaller, W. T. (1936), Mineral resources o 
 
 the region around Boulder Dam : U. S. Geol. Survey Bull. 871 
 
 197 pp. 
 Tucker, W. B., and Sampson, R. J. (1943), Mineral resources o 
 
 San Bernardino County, California : California Jour. Mines an 
 
 Geology, vol. 39, pp. 427-549. 
 
CELESTITE DEPOSITS NEAR THE SOUTHERN END OF DEATH VALLEY 
 SAN BERNARDINO COUNTY, CALIFORNIA* 
 
 By Cordell Durrell 
 
 OUTLINE OF REPORT 
 
 Page 
 A, tract 15 
 
 I reduction 15 
 
 Ology 16 
 
 stratigraphy 16 
 
 tructure 18 
 
 ■ummary of the geologic history 18 
 
 '•ccurrence of celestite 19 
 
 •rigin of the celestite 20 
 
 'hemical composition of the celestite 21 
 
 Berves _ 21 
 
 Berences _ 21 
 
 Illustrations 
 
 te 1. Geologic map. Celestite deposits near the southern end 
 of Death Valley, San Bernardino County, Cali- 
 fornia '__In pocket 
 
 ure 7. Map showing location of the celestite deposits near the 
 southern end of Death Valley, San Bernardino County, 
 California l_ 15 
 
 ABSTRACT 
 
 he celestite deposits near the southern end of Death Valley 
 in Tertiary sediments along the north base of the Avawatz 
 liitains. The sedimentary rocks of Tertiary age have been di- 
 d into four units. These are basal breccias and salt that rest 
 x giant breccia named the Amargosa chaos, red sandstone and 
 , gypsum and gypsiferous clays associated with sandstone and 
 e conglomerate, and gray and brown sandstones and conglom- 
 es. The sediments of Tertiary age are overlain unconformably 
 :he Funeral fanglomerate of Pliocene (?) age, upon which are 
 ace deposits and alluvium of Quaternary age. 
 he structures of the region are complex, and include overturned 
 5 and thrust faults and possibly low-dipping overthrusts. 
 he celestite was deposited as beds and concretions in gypsum, 
 dferous clay, clay, and sandstone and is present for a distance 
 miles along the strike of the beds. The celestite probably orig- 
 ed by replacement of the sediments that enclose it. 
 he largest of the celestite bodies is 2,100 feet long and has a 
 imum thickness of 12.7 feet. Many of the celestite bodies are 
 1 or 2 feet thick and a few tens of feet long. By far the greater 
 of the celestite is in small lenses and concretions. 
 
 INTRODUCTION 
 
 ocation of the Area. The celestite deposits near the 
 thern end of Death Valley are in Tertiary sediments 
 t flank the northern side of the Avawatz Mountains 
 . 7) . The ereseent-shaped Avawatz Mountains rise to 
 iltitude of 6,200 feet above sea level, and stand almost 
 10 feet above Saratoga Spring on the adjacent floor 
 )eath Valley. The central mass of the range is corn- 
 id of plutonic and metamorphic rocks, but a narrow 
 p of sediments and tectonic breccias of Tertiary age 
 ■nds northwestward along the northern base for about 
 piles from a point about 4 miles east of Sheep Creek 
 ings. A northwest-trending spur of the range, which 
 nds into the Death Valley trough, and two small iso- 
 i groups of hills west and northwest of the spur are 
 composed of Tertiary rocks. These geographical fea- 
 is are shown on the Avawatz Mountains topographic 
 1 of the U. S. Geological Survey. 
 
 he lands which include the celestite deposits are in 
 8 N., Rs. 4, 5, and 6 E., S. B., and T. 17 N., Rs. 5 and 
 , S. B., and belong to the Avawatz Salt and Gypsum 
 ^pany. The area ranges in altitude from 1,000 to 2,500 
 
 Approximately 50 claims, most of which are patented, 
 cover almost all of the known mineral deposits. In 1945, 
 the deposits were reached by several roads that extended 
 southward from the graded but unpaved road through 
 the south end of Death Valley (fig. 7). Fair ungraded 
 roads traversed Cave Springs Wash and Denning Springs 
 Wash. A poor road extended from the Death Valley road 
 into the Salt Basin via Pipe Line Wash, but the Salt Basin 
 could also be reached by a branch of the road in Cave 
 Springs Wash. The road to Sheep Creek Springs was 
 washed out in 1945 but could be easily repaired. A road 
 that extends northwestward along the base of the range 
 from the mouth of Sheep Creek Canyon was all but im- 
 passable (fig. 7). The deposits are as much as 14 miles 
 over unpaved roads from the paved highway at Salt 
 Springs. From Salt Springs it is 60 miles to Dunn Station, 
 the nearest railroad loading platform. The connection at 
 Riggs Station on the now-abandoned Tonopah & Tide- 
 water Railroad, mentioned in older reports on this area, 
 is no longer available. 
 
 The region has a desert climate. Snow falls on the higher 
 parts of the Avawatz Mountains, but very little precipi- 
 tation in the area of Tertiary sediments is indicated by 
 the abundant outcrops of salt. Good water is available 
 in quantity at the springs in Sheep Creek and at Sara- 
 toga Spring on the opposite side of Death Valley. A little 
 water is available at Cottonwood Spring, but there is none 
 farther west. 
 
 The strip of Tertiary sediments is flanked on the south 
 by the steep rugged slope of the Avawatz Mountains and 
 on the north by boulder-strewn alluvial fans. The area 
 of Tertiary rocks is cut into badlands. Closely spaced 
 shallow steep- to vertical-walled canyons and ravines are 
 characteristically cut in the soft sediments. 
 
 Previous Work. The first published report on the area 
 is probably that by Phalen (1914), who described the 
 stratigraphy of the Tertiary beds and the occurrence of 
 salt, gypsum, and celestite. A part of the area was exam- 
 
 1 Jlication authorized by the Director, U. S. Geological Survey 
 lanuscript submitted for publication January 1953. 
 
 Figure 7. Map showing location of the celestite deposits near the 
 southern end of Death Valley, San Bernardino County, California. 
 
 (15) 
 
16 
 
 Special Keport 32 
 
 ined by Moore (1935, pp. 1-24; Hewett et al., 1936, pp. 
 158-160), who described and measured sections at two 
 places at the western end of the area but did not visit the 
 deposits east of Cave Springs Wash. 
 
 Brief notes on the salt, gypsum, and celestite have been 
 published in several California state reports (Tucker and 
 Sampson, 1930, p. 323; 1943, p. 543) on the mineral re- 
 sources of San Bernardino County. 
 
 A recent paper by Noble (1941) on the Virgin Springs 
 area, 20 miles to the north, has an important bearing on 
 this report, for the breccias there called "chaos" by 
 Noble are present in the Avawatz area. 
 
 The base map used in the present report was made in 
 1911 by J. O. Lewis to accompany a private report on 
 the area for the Avawatz Salt and Gypsum Company. 
 
 Scope of the Report. This report is based on only eight 
 days of field work and must be regarded merely as a 
 reconnaissance. The work was clone as a part of the "World 
 War II program of the IT. S. Geological Survey for the 
 investigation of strategic minerals. All the celestite de- 
 posits exposed within the mapped area probably were 
 found, but the exact dimensions of the numerous beds 
 were not determined, so that precise estimates of re- 
 serves cannot be made. Celestite may be present beyond 
 the limits of this mapped area, plate 1, though such de- 
 posits are unknown. Many problems in structure, stra- 
 tigraphy, and origin of the rocks and mineral deposits 
 remain to be solved. 
 
 Acknowledgments. The writer is indebted to B. N. 
 Moore for the sections at the Celestite Hills, which were 
 taken verbatim from his report. L. F. Noble furnished 
 the writer with a copy of the base map used in this report, 
 and also contributed orally much information about the 
 immediate area and the Death Valley region in general. 
 A. C. Daley assisted in the field and in the preparation of 
 the maps. H. H. Kerkthoff, Jr., of the Avawatz Salt and 
 Gypsum Company, San Marino, California, gave permis- 
 sion to make the study and to publish the results. 
 
 GEOLOGY 
 
 Stratigraphy 
 
 Because the concept of the stratigraphy presented be- 
 low is based on only a few days' work, it can be regarded 
 only as provisional. Careful study and mapping will be 
 required to solve all the problems involved. The oldest 
 rocks of the district, which do not appear on plate 1, are 
 those of the higher parts of the Avawatz Mountains. They 
 were not examined by the writer, but judging from the 
 material brought down by the streams, they are plutonic 
 and metamorphic rocks that are doubtless pre-Tertiary in 
 age. The crystalline rocks of the range are separated from 
 the Tertiary sequence by a broad crush zone of gouge 
 and breccia that is probably the Garlock fault. 
 
 Amargosa Chaos. The oldest rocks north of the Gar- 
 lock fault are those of the puzzling giant breccia, named 
 the Amargosa chaos by Noble (1941, pp. 964-965) for 
 its occurrence in the Amargosa Range on the east side of 
 Death Valley, 20 miles to the north. The Amargosa chaos, 
 which is described in great detail in Noble's report, is 
 believed by him to be a gigantic tectonic breccia that rests 
 on the Amargosa thrust fault. Three phases of the chaos 
 are distinguished by the character of the constituent 
 
 blocks and their structural position. The Amargosa chao: 
 of the Avawatz area is the latest and highest phase, ac 
 cording to Noble (oral communication, 1945) and wai 
 named by him the Jubilee phase. 
 
 The chaos of the Avawatz area has the typical structure 
 described by Noble. Blocks, of dimensions ranging fron 
 inches to scores of feet, bounded by faults and shatterei 
 internally, yet with the internal structures not seriousl; 
 disturbed, are closely packed against each other withou 
 intervening matrix or gouge. The blocks are predomi 
 nantly of granitic rocks, and relatively large areas con 
 tain nothing but rocks of that type. Elsewhere dolomites 
 limestones, quartzite, or sandstones are mixed with gra 
 nitic rocks, or are locally predominant. Hornfelsed am 
 epidotized thin-bedded calcareous shales and mica schist 
 are locally abundant. The base of the chaos has not bee 
 found within the area, and its thickness is not known. Th 
 age of the Amargosa thrust, and therefore the chaos res 1 
 ing on it, is not older than Miocene according to NobI 
 (1941, p. 981), for the Jubilee phase contains Tertiar 
 rocks that are probably Miocene in age. 
 
 Andesite. Southeast of the Jumbo Salt area there is 
 narrow strip of purplish-gray vesicular andesite that 
 in fault contact with the Amargosa chaos. On the soutl 
 ern side the andesite is apparently in depositional conta< 
 with red sandstones of the succeeding salt-bearing bed 
 Thus the andesite appears to be a flow, older than the sa 
 beds, and therefore probably originally erupted onto tl 
 surface of the Amargosa chaos. Possibly, however, tl: 
 andesite is properly a part of the chaos, though Tertiar 
 volcanic rocks have not been seen elsewhere in the cha< 
 in this district. In the Virgin Springs area the Jubih 
 phase does contain Tertiary andesite and other volcan 
 rocks. 
 
 Tertiary Sediments. The top of the Amargosa eha< 
 is well exposed in the Salt Basin, where it is compose 
 largely of quartzite that is overlain by a sedimentai 
 breccia of angular blocks of the same quartzite. The sec 
 mentary breccia is not more than 30 feet thick, shows i 
 internal bedding, and is overlain by red salt clays ai 
 salt. North of the Jumbo Salt area, there are poorly be 
 ded breccias of black sandstone, and hornfelsed and epid 
 tized calcareous shale identical with those found in tl 
 chaos that are equivalent to and in part older than tl 
 salt. The chaos is present north of the breccia, and, thou;. 
 the contact between it and the breccias was not examhn 
 or mapped, the relationship is almost certainly the sar 
 as that at the Salt Basin. Apparently sedimentary bre 
 cias locally derived from the underlying chaos were c 
 posited on the chaos after overthrusting ceased. 
 
 At Big Gypsum Hill, west of Cave Springs Wash,! 
 well-bedded unit mapped as conglomerate but consistii 
 of blocks of granitic rocks in a sandy matrix, is believ 
 to occupy the same position as the breccias farther ea 
 The structure is complex, however, and this interpret 
 tion may be incorrect. 
 
 Possibly the breccia and conglomerate should be cc 
 sidered more properly as part of the Amargosa eha<. 
 Either these beds were deposited diseontinuously in loci 
 basins or they are merely phases of the underlying cha <• 
 
 The breccias are succeeded by the salt-bearing beds, i 
 the central part of the area there are two strips of Ter- 
 ary sediments separated by a strip of Amargosa cha. 
 
Strontium Deposits, Southern California 
 
 17 
 
 ;he salt-bearing beds in the northern strip consist of 
 >ek salt alternating with laminated red shales, massive 
 i'd clays, fine thin-bedded red sands, and beds of breccia 
 iith a matrix of red clay. The blocks of the breccias are 
 ..entical with those in the breccia below the salt and in 
 lases of the Amargosa chaos. In both the Salt Basin and 
 lie Jnmbo Salt area are breccias of the black sandstone 
 id epidotized shale with a matrix of salt. 
 
 Almost no pure salt is present in the mapped part of the 
 suthern strip of Tertiary sediments, though one of the 
 rgest salt bodies of the area is in that strip west of Cave 
 )rings Wash. East of Cave Springs Wash the salt beds 
 Insist of laminated red shale, massive red clay, fine to 
 !>arse red sandstone, and bright-yellow shale and sand. 
 •rusts of salt resulting from efflorescence are present 
 >arly everywhere, and a whitish bloom of salt is common, 
 reshly broken rock tastes distinctly salty. 
 
 The thickness of the salt beds has not been measured, 
 it it ranges from about 100 to 600 feet. In the Jumbo 
 dt area, where the red beds and salt combined are thin, 
 e greater part of the thicker Salt Basin section is repre- 
 |nted by breccia. The lateral gradation is accomplished 
 rough thickening of the basal and interbedded breccias 
 id thinning of the salt beds in the intervening area. 
 
 Gradation from salt beds to breccia toward the north 
 ross the axis of the anticline north of the Jumbo Salt 
 
 also a result of the same cause. This is shown diagram- 
 atically in section D-D', plate 1. The breccias in salt 
 atrix are well exposed in the crest of the anticline on 
 e line of the section, and salt bloom is present on the 
 
 rface of the breccia as far as the summit of the hill at 
 Je north end of the section. Interbedded salt and breccia 
 ie well exposed in the cliffs on the east side of the large 
 ish east of the Jumbo Salt area. South and southeast 
 ■ the Jumbo Salt area red salty sand and shale appear 
 
 be interbedded with the Amargosa chaos, though the 
 ructure is complex and the relationship is therefore 
 icertain. 
 
 lOne small lens of celestite was found in the salt-bear- 
 fa; beds 2,000 feet east of Cave Springs Wash, in the 
 Jiiithern strip of Tertiary rocks. 
 
 The salt beds are overlain by a sequence of highly 
 ! psiferous beds of light-tan shale and sandstone that 
 tatains nearly all of the celestite. The contact between 
 |3 salt beds and the gypsiferous beds is gradational. 
 Cpsuni is present to a minor degree in the top of the 
 liderlying red beds, but becomes abundant at the hod- 
 s' i where the color changes. Gypsum is most abundant 
 i the lower part of the sequence, where it is present in 
 lie-grained form in beds a fraction of an inch to several 
 i 't thick that alternate with tan and greenish-yellow 
 t ;.ys. The gypsum is mostly tan, gray, or greenish from 
 ( ( stic impurities. The lower 50 feet of the sequence is 
 1 edominantly gypsum. South of Salt Basin, northwest 
 <j Cottonwood Spring, and in the Celestite Hills streaks 
 id lenses of powdery manganese oxide up to an inch 
 1 ck and 10 feet long are in the gypsum, in many places 
 <;sely associated with celestite. 
 
 jypsum is less abundant higher in the shale and sand- 
 i ne sequence, but is scattered through the clay shale 
 Si sandstone in beds up to several feet thick. At the 
 < item end of the area between Cottonwood Spring and 
 > eep Creek the gypsiferous unit is party conglomerate. 
 
 The gypsiferous beds in the southern strip of sediments 
 are neither so rich in gypsum nor so distinctly different 
 from the salt beds as they are in the northern strip. Red 
 and gray sands and red, gray, and tan shales alternate 
 with thin beds of impure gypsum. 
 
 Cross-bedding and graded-bedding are well developed 
 in the sandstone of the gypsiferous unit, and numerous 
 observations in the vicinity of the Salt Basin and the 
 Jumbo Salt area show that the top of the beds is upward 
 or toward the south. The salt beds therefore lie beneath 
 the gypsiferous unit. The thickness of the gypsiferous 
 unit is probably between 600 and 800 feet. 
 
 Celestite forms nodules or concretions of small size in 
 the gypsum and gypsiferous shale of the northern strip 
 of sediments and in the Celestite Hills. Most of the 
 celestite beds are closely associated with gypsum, but 
 some are present in sandstone and shale without gypsum, 
 particularly in the southern strip of sediments. 
 
 The next higher unit consists of a heterogenous group 
 of sediments that rest conformably and with gradational 
 contact on the gypsiferous unit. Immediately southwest 
 of the Salt Basin this unit consists dominantly of yellow 
 and brown well-cemented sandstone, and therefore it 
 crops out more prominently than the lower beds. Gray to 
 brown clay shale and thin beds of gypsum constitute a 
 minor fraction of the section. Here, and in the cliffs along 
 Pipe Line Wash east of Salt Basin, cross-bedding and 
 graded-bedding in the sandstone show that the beds are 
 in normal position above the gypsiferous unit. 
 
 West of Cottonwood Spring in the south strip of sedi- 
 ments this higher unit consists largely of predominantly 
 brown conglomerate and sandstone. The section becomes 
 more conglomeratic and the pebbles become larger to- 
 ward the top of the section. The pebbles of the conglom- 
 erate are well-rounded, are in an abundant matrix of 
 sand, and the bedding is well developed. From their 
 general aspect the sediments are probably lacustrine in 
 origin, though undoubtedly they are a near-shore facies. 
 They are definitely not fanglomerates, as are the rocks of 
 the succeeding Funeral fanglomerate. The unit has not 
 been measured, but it is probably nearly a thousand feet 
 thick. 
 
 All of the sediments above the Amargosa chaos are 
 probably Middle Tertiary or younger. If the Amargosa 
 thrust is not older than Miocene, and if the Amargosa 
 chaos contains Miocene rocks, then the sediments of the 
 Avawatz are probably not older than upper Miocene, 
 and they may be in part Pliocene. 
 
 Funeral Fanglomerate. Gray to tan unconsolidated 
 fanglomerate that rests unconformably on the sediments 
 of Tertiary age are present south of the southern strip 
 of sediments east of Cave Springs Wash, in Big Gypsum 
 Hill, and in the Celestite Hills. The unconformity is well 
 exposed at numerous places. These rocks have been corre- 
 lated by Noble (oral communication, 1945) with the Fu- 
 neral fanglomerate, which was named originally for an 
 exposure farther north in the Death Valley region. Ac- 
 cording to Noble the Funeral fanglomerate is probably 
 late Pliocene but may be in part early Pleistocene in 
 age. The nature of the unconformity is shown dia- 
 gramatically in sections A-A' and C-C, plate 1. 
 
 Quaternary Deposits. Terrace deposits of fanglomer- 
 ate and stream gravel, formed in an earlier erosion cycle, 
 
18 
 
 Special Report 32 
 
 cap many of the ridges far back toward the main mass 
 of the Avawatz Mountains, and rise more than 100 feet 
 above the level of the present streams. 
 
 Structure 
 
 The principal structural features of the region are il- 
 lustrated on plate 1. The sections are only diagrammatic, 
 however, as sufficient data for accurate sections could not 
 be collected in the brief time devoted to the study. 
 
 Two major faults of the region are virtually unknown 
 to the writer. In the Virgin Springs area to the north, the 
 base of the Amargosa chaos is the Amargosa thrust. Pre- 
 sumably the Amargosa thrust is also present at the base 
 of the chaos in the Avawatz area, but it is not exposed at 
 any of the localities visited. South of the Tertiary sedi- 
 ments and separating them from the crystalline complex 
 of the Avawatz Mountains is a huge crush zone of gouge 
 and breccia that was only casually examined in Sheep 
 Creek. Several hundred feet of crushed rock is visible 
 there, and the southern contact was not yet evident. The 
 crush zone is subject to rapid erosion and thereby be- 
 comes intricately gullied. The distribution of the gullied 
 ground suggests that the fault zone extends the full 
 length of the mapped area. According to Noble (oral com- 
 munication, 1945) this is the Garlock fault, which extends 
 far to the west of the area and beyond the town of Mojave, 
 to where it eventually meets the San Andreas rift. 
 
 After the episode of thrusting that resulted in the for- 
 mation of the Amargosa chaos, the region became the site 
 of a lake in which Tertiary sediments were deposited. The 
 lake sediments and the Amargosa chaos Avere then folded 
 and probably faulted. The area was then eroded and the 
 Funeral fanglomerate was deposited across the cut sur- 
 face. The beds were then folded and faulted a second 
 time. Probably normal faulting, unaccompanied by fold- 
 ing, took place at a still later date, for the large topo- 
 graphic features of the- region as a whole are of the basin 
 and range type. 
 
 The double cycle of folding is illustrated in section 
 A-A', taken across the Celestite Hills. Here the first 
 period of folding was more intense than the second. West 
 of Cave Springs Wash the Funeral fanglomerate is gently 
 arched into an anticline tbat spans the full width of both 
 strips of sediments. Although this part of the area was 
 not mapped, the anticline does not appear to be broken by 
 the large fault that separates the north strip of Tertiary 
 sediments from the Amargosa chaos in the Salt Basin. 
 The evidence suggests that the major faulting in the Ter- 
 tiary accompanied the first period of folding. 
 
 The fault mentioned above as present south of Salt 
 Basin is shown in section C-C as a reverse fault in the 
 middle limb of an overturned anticline. At the Jumbo 
 Salt area the relationship is the same. Presumably the 
 same fault continues eastward to and beyond Sheep 
 Creek, and everywhere forms the south boundary of the 
 northern strip of Tertiary sediments. 
 
 The structural relations of the southern strip of Ter- 
 tiary sediments are less clear. South of the Jumbo Salt 
 area the structure is so complex that little could be made 
 of it in the time available. A fault lies between the Amar- 
 gosa chaos and the andesite; farther south another lies 
 between the chaos and the salt-bearing beds. Between the 
 two faults are alternating strips of chaos and salt-bear- 
 ing sediments. Whether these strips are a depositional 
 
 sequence or an imbricate structure remains to be deter- 
 mined. 
 
 The structure of Big Gypsum Hill is exceedingly in- 
 tricate and involves low-dipping thrusts that have 
 brought the gypsiferous unit of the Tertiary over Amar 
 gosa chaos and the lower conglomerate. Well-exposec 
 zones of gouge make the writer sure that the contact sur 
 faces are faults. Section B-B' is an attempt to explain thi; 
 structure. The arching of the thrust may be the result o: 
 folding at the time of the second cycle, or it may con 
 ceivably be an original curvature. Further study is re 
 quired before a final interpretation can be made. 
 
 At the northern end of section B-B' the Funeral fan 
 glomerate is over-ridden by the gypsiferous beds on a re 
 verse fault. This fault is important, for the fanglomerate 
 are overturned beneath it, yet they have a gentle dip onb 
 a few hundred feet away. Another post-Funeral fan 
 glomerate reverse fault that dips in the opposite directioi 
 is present at the head of Pipe Line Wash, where the faul 
 is perfectly exposed at several places. Farther northwes 
 the Funeral fanglomerate rests unconformably on th 
 gypsiferous beds ; so the fault probably passes wholl; 
 within the fanglomerate in that direction. 
 
 The marked lack of mapped cross-faults is probably f o 
 want of more detailed work. A small cross-fault is locate* 
 at the west end of the Jumbo Salt area, and a relativel; 
 large cross-fault must exist beneath the alluvium of th 
 wash west of Cottonwood Spring, for geologic sequence 
 on the two sides of the wash are different. 
 
 Summary of the Geologic History 
 
 Noble (1941, pp. 941-999) postulated the formation o 
 the Amargosa chaos by movement along a flat thrust. I 
 this mass of rock is of tectonic origin, it is easy to pictur 
 a surface on it that lacked complete drainage. The writer 
 impression is that there were one or more closed basins o 
 that surface in the area, and that these were filled by 
 lake or lakes. In the early stages the basins were the site 
 of deposition of sedimentary breccias produced by redii 
 tribution of the surface rocks of the chaos itself. The el 
 mate must have been arid, for some of the breccias haV 
 a matrix of salt. Continued sedimentation and evapor; 
 tion resulted in the deposition of salt beds of considerabl 
 thickness associated with beds of breccia, and red shal 
 and fine-grained red sandstone were also depositee 
 Around the margins of the basins of evaporation red seel 
 ments that contain only a little salt were deposited. Prol 
 ably the lakes then expanded, or perhaps several lake 
 coalesced, as the water deepened to form a larger lake i 
 which the succeeding series of gypsiferous beds were d 
 posited. At this time the celestite was deposited also. Tl 
 subsequent beds were less gypsiferous and more sand, 
 and eventually conglomerate was deposited. The coar: 
 clastic sediments may represent marginal deposits, or the 
 may represent a final filling of the basin. One cannot 1 
 sure that the drainage remained closed throughout th 
 time, but it likely did, as gypsum persists into beds ne; 
 the top. 
 
 The sediments were then compressed closely and tl 
 folds were overturned. Reverse faults developed in tl 
 overturned section, and the underlying chaos was thru 
 over the gypsiferous unit. In the northwest part of tl 
 area a thrust developed at a low angle, but younger bei 
 remain over older beds. 
 
Strontium Deposits, Southern California 
 
 19 
 
 After a subsequent period of erosion the Funeral fanglo- 
 j ^rate was deposited across the folded and faulted older 
 
 ;rtiary rocks. The Funeral fanglomerate was then folded 
 ; to gently dipping anticlines and synclines. Reverse f ault- 
 :g accompanied this deformation, and the older Tertiary 
 
 cks were thrust over Funeral fanglomerate along the 
 :Tthern and southern sides of the area. 
 
 Renewed erosion dissected the Funeral fanglomerate, 
 jid resulted in the deposition of fanglomerates which now 
 jle terrace deposits. A further slight uplift, or lowering 
 j the base level, has caused the entrenchment of the pres- 
 et streams below the terrace level. The role of the Garlock 
 pit in this history is unknown. 
 
 Occurrence of Celestite 
 
 1 Celestite is found in both the northern and the southern 
 
 rips of Tertiary sediments, mostly in the gypsiferous 
 
 lit. It is present over a distance of approximately 7 miles, 
 
 om a little west of Cottonwood Spring to the Celestite 
 
 ills. The most important deposits are in the southern 
 
 ; ?ip east of Cave Springs Wash and in the Celestite Hills. 
 
 Individual beds or groups of celestite beds, where large 
 
 >; ough to be shown without too much exaggeration, were 
 
 ipped separately. That part of the gypsiferous unit 
 
 lich contains thin beds and concretions of celestite too 
 
 tall to be shown on the map was mapped as a separate 
 
 lit. 
 
 The celestite is present in three related modes of deposi- 
 >n : as small nodules or concretions in gypsum, as typical 
 iheroidal concretions in clastic sediments, and as beds 
 : gypsum and in clastic sediments usually closely asso- 
 rted with gypsum. 
 
 The nodules in gypsum are composed of very pure dense 
 ■ lite fine-grained celestite. They range in diameter from 
 '. :s than an inch to 6 inches. Most of them are between 
 and 3 inches. They are generally regular in shape; 
 ] ttened or elongated spheroidal forms are most common. 
 . few have knobby surfaces, and most of them have a 
 ' iread crust" appearance, owing to polygonal cracks over 
 ; )art of the surface. 
 
 These celestite concretions are strewn abundantly over 
 fe surface of the gypsiferous beds in the Celestite Hills 
 ; : d at Big Gypsum Hill. They also are present in the gyp- 
 m south of Salt Basin, and are sparingly present else- 
 T iere in the area. At the Celestite Hills they are very 
 :undant on the surface, but they can be found in place 
 ( ly with difficulty. Apparently the nodules were concen- 
 Uted on the surface as the surface was lowered by ero- 
 s;n. Several concretions found in place there show the 
 'read crust" surface, which is therefore an original 
 fiture. 
 
 The celestite concretions in the clastic sediments are 
 1 s pure than those in the gypsum. Most of them are gray 
 ( brown in color ; many are highly porous and contain 
 s id grains, particularly in the outer portions. They 
 i lge in size from an inch in diameter to 15 feet in length 
 <1 3 feet in thickness. They usually are in interbedded 
 c y shale, silty or sandy shale, and sandstone. A number 
 c the smaller bodies shown on the map are of this type. 
 The beds of celestite vary considerably in appearance 
 i m place to place. In the Celestite Hills, where several 
 c sely spaced beds form a large lens, they are in gypsum 
 i erbedded with shale. Some of the celestite is porous 
 c 1 granular and some is dense and granular. Much of it 
 
 is composed of matted acicular crystals of celestite 1 to 
 3 mm long in either dense or porous aggregates. It varies 
 in color, depending probably on included impurities. 
 Some is white, light green, and pink ; most of it is gray 
 and some is quite black, owing to included manganese 
 oxides. Single celestite beds range in thickness from an 
 inch to H feet. Several beds separated only by partings 
 of clay or gypsum constitute celestite-rich units as much 
 as 6 feet thick. The surfaces of the beds are generally well 
 defined, but close examination revealed a narrow transi- 
 tion zone between the celestite and the adjacent sedi- 
 ments. The transition zone, which is only a few millimeters 
 thick, consists of celestite, sand grains, clay, and gypsum. 
 The amount of celestite decreases gradually, and the 
 amount of sediment increases outward from the celestite 
 bed. Moore (Hewett et al., 1936, p. 159) measured five 
 sections in the Celestite Hills, three of which are repro- 
 duced below. Sections 1, 2, and 3, located respectively 
 at the middle of the celestite lens, at the thickest part of 
 the lens, and at the north end, are Moore's sections 1, 3, 
 and 4 and 5 combined. 
 
 Section 1. Celestite Hilh: middle of lens. 
 
 Feet Inches 
 
 Gypsum 4 
 
 Massively bedded medium-grained celestite rock 3 
 
 Green gypsiferous celestite rock 3 
 
 Gypsiferous celestite rock 2 2 
 
 Greenish gypsiferous clayey celestite rock 3 
 
 Massively bedded medium-grained celestite rock 2 2 
 
 Manganiferous, gypsiferous celestite rock 1 + 
 
 Total thickness 13 + 
 
 Total celestite 9 
 
 Section 2. Celestite Hills: thickest part of lens. 
 
 Feet Inches 
 
 Gypsum 
 
 Massively bedded medium-grained celestite rock, man- 
 ganiferous at base 3 6 
 
 Massively bedded medium-grained celestite rock 2 6 
 
 Manganiferous gypsum 1 6 
 
 Massively bedded medium-grained celestite rock, man- 
 ganiferous 6 
 
 Massively bedded medium-grained celestite rock 1 7 
 
 Interbedded celestite rock and gypsum 6 
 
 Gypsum 5 6 
 
 Gypsiferous clays 
 
 Total thickness 22 5 
 
 Total celestite 13 11 
 
 Section 3. Celestite Hills: north end of lens. 
 
 Feet Inches 
 Manganiferous gypsum, with masses of medium-grained 
 
 celestite rock near base 4 
 
 Gypsiferous and manganiferous celestite rock 2 
 
 Manganiferous gypsum ; contains much celestite in 
 
 scattered crystals 1 6 
 
 Gypsum with reniform nodules of medium-grained 
 
 celestite H 
 
 Nodules of medium-grained celestite, forming bed 6 
 
 Gypsum 4 
 
 Massively bedded medium-grained celestite rock 3 
 
 Gypsum 4 
 
 Gypsiferous clays 
 
 Total thickness 27 3 
 
 Total celestite 6 9 
 
 The bedded celestite in the southern strip of sediments 
 east of Cave Springs Wash is in fine red and gray sand- 
 stone and red shale immediately above gypsum. The celes- 
 tite is gray on fresh surfaces, but weathers dull brown. 
 
20 
 
 Special Report 32 
 
 The bulk of it is fine grained and porous in texture, and 
 some of the cavities are lined with small crystals. Most 
 of the celestite feels light in the hand. Because of the 
 porosity the aggregate specific gravity is probably less 
 than 3. Internal bedding planes are usually lacking, but 
 faint traces of bedding often present near the margins 
 are the result of included sand grains. Nearly all of the 
 celestite at this locality contains a little sand. The surfaces 
 of the beds are smooth and well defined, but a narrow 
 transition zone separates the celestite from the adjacent 
 clastic sediments. Concretions of celestite are present also ; 
 they are confined to certain zones where they are separated 
 laterally from each other by a few inches to several feet 
 of sediment. 
 
 A section measured across the large body of celestite at 
 a sharp bend in the creek about 1,200 feet east of Cave 
 Springs "Wash is presented below as section 4. 
 
 Section .}. East of Cave Springs Wash. 
 
 Feet 
 
 Thin-bedded red and gray sandstone and shale 
 
 Massive porous celestite in short concretionary lenses 1.0 
 
 Thin-bedded red silty and sandy shale 7.2 
 
 Massive porous celestite 0.8 
 
 Thin-bedded red silty sandstone 6.1 
 
 Massive porous celestite 2.4 
 
 Red and gray silty shale and sandstone 13.5 
 
 Massive porous celestite in short concretionary lenses 1.0 
 
 Red shale and silty sandstone 15.7 
 
 Massive porous celestite 3.3 
 
 Thin-bedded red silty shale and silty sandstone 6.4 
 
 Massive porous celestite 2.2 
 
 Red clay 0.4 
 
 Massive porous celestite 2.0 
 
 Thin-bedded red and gray sandstone and silty clay 
 
 Total thickness 62.0 
 
 Total celestite 12.7 
 
 The separately mapped lenses of celestite south of Salt 
 Basin are like the last-mentioned beds. The celestite beds 
 in the larger body range in thickness from 0.3 to 1 foot. 
 The total thickness of celestite is about 4 feet. All of it is 
 porous and feels light in the hand. Both of the lenses 
 shown on the map terminate in depth above the level of 
 the adjacent streams. 
 
 A few of the larger bodies in the vicinity of the Jumbo 
 Salt area are shown on the map, though greatly exag- 
 gerated in thickness. They are mostly no more than 1^ 
 feet thick and 30 to 50 feet long. Four prominent lenses 
 are present at the east end of the Jumbo Salt area. The 
 northern lens contains about 10 feet of celestite in 25 feet 
 of beds. The two central lenses are each about 1^ feet 
 thick, and the southern lens consists of a chain of short 
 concretionary beds 1 to 2 feet thick and 10 to 25 feet long. 
 
 In addition to the celestite bodies separately shown 
 there are innumerable beds an inch to a foot thick and 5 
 to 100 feet long in that part of the gypsiferous unit shown 
 as Tg on plate 1. This unit ranges from about 100 feet 
 at the west end of the Jumbo Salt area to 50 feet near the 
 east end, beyond which it thickens again. Five to 10 per- 
 cent of this unit is estimated to consist of porous celestite 
 in thin beds and concretions that weather dark brown. It 
 is also estimated that not more than 70 percent of celestite 
 rock is strontium sulfate. The celestite in the northern 
 strip of sediments between the Jumbo Salt area and the 
 wash northwest of Cottonwood Spring is similar to that in 
 the Celestite Hills. It is mostly in gypsum that contains 
 
 streaks of manganese oxides ; moreover, most of the celes- 
 tite contains manganese. The maximum thickness of the 
 lens shown on the map is about 4 feet. Concretions and 
 thin lenses are also included in the celestite-bearing beds 
 there to an extent not exceeding 5 percent. 
 
 The celestite in Big Gypsum Hill is similar to that in 
 the Celestite Hills. It is mostly in gypsum as beds nol 
 more than a foot thick, and in short concretionary lenses 
 a foot thick and as much as 10 feet in diameter. Small 
 nodules are present in the gypsum and are strewn ovei 
 the surface of the hills. The beds lie nearly flat, and the 
 celestite-bearing part of the section is exposed in severa" 
 trenches. The maximum thickness of celestite is about l 
 feet, and the average thickness is probably about 1 foot 
 Most of the celestite is porous and weathers brown ; hut 
 a little is dense, light-colored, and heavy. 
 
 Origin of the Celestite 
 
 Beds and concretions of celestite, widely distributee 
 laterally and rather closely confined stratigraphically, ir 
 lake sediments that also contain salt and gypsum lead a' 
 once to the assumption that the celestite is sedimentary ir 
 origin. The writer has found no reason to doubt that this 
 is true. Moore (1935, pp. 3, 15) was of the opinion tha 1 
 the celestite was sedimentary, and also that it was a direc 
 precipitate from the lake waters. He stated that th< 
 celestite bodies "show no signs of replacement, but ar< 
 apparently the result of deposition of masses of crystal 
 line celestite and gypsum as a chemical precipitate." The 
 opinion of the present writer is, however, that the celestiti 
 bodies were formed by replacement. 
 
 In the Celestite Hills, at Big Gypsum Hill, south o: 
 Salt Basin, and northwest of Cottonwood Spring, smal 
 nodules of dense white celestite occur in the gypsum. Un 
 doubtedly these nodules were formed by some process o 
 replacement after the gypsum was deposited. They hav 
 no internal structures to indicate that they formed h 
 accretion. It is difficult to conceive of them as direct pre 
 cipitates. The strontium sulfate must have been precipi 
 tated from the connate water that saturated the gypsum 
 
 Concretions of porous celestite in clastic sediments hav 
 been described in the preceding section. They range frori 
 an inch in diameter to 15 feet in length and 3 feet ii 
 thickness. They are smoothly rounded at the margins 
 truncate the bedding of the enclosing sediments, and the; 
 are not internally bedded. The abutting bedding plane 
 show distinctly on the surface of the concretions, whicl 
 are impure near the margins owing to residual inclusion 
 of sand and clay. The present writer believes that thes 
 concretions were formed by replacement of the clasti 
 sediments without disturbance of the stratification of th 
 surrounding material. No concept of direct precipitatio: 
 from the lake waters can account for their form an* 
 boundary relationships. Like the concretions in gypsun 
 they must have been formed by the precipitation of stron 
 tium sulfate from connate waters within the sediments 
 
 The celestite beds in clastic sediments are not differen 
 from the concretions in the clastic sediments other tha: 
 in their dimensions, for they grade continuously in siz 
 from thin short beds that are only very thin concretion 
 up to the largest beds which are 3 feet thick and severa 
 hundred feet long. Concretions a foot thick and severa 
 feet in diameter, confined to a bed and separated fror 
 each other in the bedding plane by only a few inches t 
 
Strontium Deposits, Southern California 
 
 21 
 
 few feet of sediment, are present at two horizons in 
 •etion 4, east of Cave Springs Wash. If these concretions 
 id grown a little larger, they would have coalesced to 
 »rm beds only a foot thick. Texturally and structurally 
 ley are identical with the neighboring celestite beds, 
 hese facts indicate to the writer that the beds of celestite 
 •e only greatly elongated concretions. They may aetu- 
 \\y have developed by the growth and coalescence of 
 lmerous concretions formed at the same horizon and 
 >ntrolled in position by lithologic differences in the pre- 
 ;isting sediments. Under this view the beds are also re- 
 acement deposits. 
 
 i In the Celestite Hills there are beds in gypsum that are 
 mposed of matted needles of celestite. Most of the 
 >edles are so disposed that their length is in, or nearly in, 
 e bedding plane. Moore (1935, pp. 3, 15) believed that 
 is celestite was precipitated directly from the lake 
 aters above. This possibility must be seriously enter- 
 ined, but if it is the origin of these beds, it accounts for 
 dy a very small part of the celestite in the district. On 
 e other hand, it is equally probable, perhaps more so in 
 |ew of the associated celestite nodules of replacement 
 igin, that this material was also formed by replacement, 
 ie formation of relatively pure crystals of many min- 
 !als in wet clays of the playas of the desert region by 
 ecipitation of their constituents from the interstitial 
 liter of the sediments is a familiar phenomenon. The 
 ■ ientation of the needles in the bedding planes could well 
 the result of the influence of bedding planes, or of clay 
 ; d gypsum crystals oriented in sedimentation. The au- 
 or favors the view that these beds are also of replace- 
 ment origin. 
 
 Chemical Composition of the Celestite 
 
 Three chemical analyses of celestite are available from 
 italen's report (1914, p. 530). Analyses I and II, by 
 " . C. AVheeler, of the U. S. Geological Survey, are partial 
 < alyses of material collected by Phalen near the west 
 id of the area studied. Analysis III, by R. A. Perez, of 
 1 s Angeles, California, was furnished to Phelan by the 
 . awatz Salt and Gypsum Company. 
 
 I II in 
 
 !rO 38.41 47.92 50.99 
 
 JaO 0.75 
 
 $aO Trace 
 
 i0 3 42.38 
 
 [iO, 0.92 
 
 ■: 
 
 Total 95.04 
 
 rSO, - 68.11 84.98 90.42 
 
 average, 81 percent. 
 
 The data are hardly sufficient to use in calculating re- 
 serves for such a large area, but, in the judgment of the 
 writer the bulk of the celestite is no better in grade than 
 the average of the three analyses, which is therefore satis- 
 factory for preliminary estimates. 
 
 RESERVES 
 
 No precise estimates can be given of the reserves of 
 celestite in the area studied, for the dimensions of the 
 many celestite bodies have not been accurately deter- 
 mined, and the analytical data are insufficient. It is 
 estimated, however, that the deposits contain between 
 250,000 and 300,000 tons of celestite rock to a depth of 
 50 feet. 
 
 This estimate includes all the exposed celestite bodies 
 that can possibly be considered to have economic im- 
 portance, and some that evidently do not. In addition 
 there are numerous small lenses and concretions that 
 contain from a ton to several hundred tons of celestite. 
 The calculations are based on an assumed weight of the- 
 celestite rock of 200 pounds per cubic foot, which corre- 
 sponds to a specific gravity of slightly more than 3. 
 
 Almost half of the total celestite is in the celestite- 
 bearing gypsiferous beds in the Jumbo Salt area. Yet 
 considering that the celestite is widely distributed 
 through at least 10 times that amount of shale, sand, and 
 gypsum, and that only a few small bodies could be mined 
 for celestite rock alone, it is unlikely that any of the- 
 celestite could be profitably recovered. The larger body 
 at the Salt Basin is very small, though it could be easily 
 mined. It is probably not of economic importance. 
 
 The two areas that are most likely to be of commercial 
 importance are the Celestite Hills and the area east of 
 Cave Springs Wash in the southern strip of sediments. 
 
 REFERENCES 
 
 Hewett, D. F., Moore, B. N., Callaghan, Eugene, Nolan, T. B. r 
 Rubey, W. W., and Schaller, W. T. (1936), Mineral resources 
 of the region around Boulder Dam : U. S. Geol. Survey Bull. 
 871, 197 pp. 
 
 Moore, B. N. (1935), Some strontium deposits of southeastern 
 California and western Arizona : Am. Inst. Min. Met. Eng. Tech. 
 Pub. 599, pp. 1-24. 
 
 Noble, L. F. (1941), Structural features of the Virgin Springs 
 area, Death Vallev, California : Geol. Soc. America Bull. 52, 
 pp. 941-999. 
 
 Phalen, W. C. (1914), Celestite deposits in California and Ari- 
 zona : U. S. Geol. Survey Bull. 540, pt. 1, pp. 521-533. 
 
 Tucker, W. B., and Sampson, R. J. (1930), Los Angeles field divi- 
 sion : California Jour. Mines and Geology, vol. 26, pp. 202-324. 
 
 Tucker, W. B., and Sampson, R. J. (1943), Mineral resources of 
 San Bernardino County, California : California Jour. Mines and. 
 Geology, vol. 39, pp. 427-549. 
 
THE SOLOMON AND ROSS STRONTIANITE DEPOSITS, MUD HILLS 
 SAN BERNARDINO COUNTY, CALIFORNIA * 
 
 By Cordell Durrell 
 
 OUTLINE OF REPORT 
 
 Page 
 
 !>stract 23 
 
 itroduction 23 
 
 eology of the Mud Hills 24 
 
 eology of the Solomon strontianite deposit 25 
 
 eology of the Ross strontianite deposit 34 
 
 eferences 36 
 
 Illustrations 
 Plate 2. Geologic map of the Ross strontianite deposit. 
 Mud Hills, San Bernardino County, Cali- 
 fornia In pocket 
 
 3. Structure sections, east end of Mud Hills, 
 
 San Bernardino County, California In pocket 
 
 4. Columnar sections, Tertiary beds of the Bar- 
 
 stow syncline, east end of Mud Hills, San 
 Bernardino County, California In pocket 
 
 5. Geologic map of the Solomon strontianite 
 
 deposit, Mud Hills, San Bernardino County, 
 California In pocket 
 
 6. Structure sections, Solomon strontianite de- 
 
 posit, Mud Hills, San Bernardino County, 
 California In pocket 
 
 7. Map showing abundance of strontianite, Solo- 
 
 mon strontianite deposit, San Bernardino 
 
 County, California In pocket 
 
 igure S. Map showing location of the Solomon and Ross 
 
 strontianite deposits 23 
 
 9. Detail of strontianite-rock lens 30 
 
 10. Detail of strontianite rock transgressing bedding 30 
 
 11. Diagrams showing strontianite rock localized by faults 31 
 
 12. Location and claims map, Ross and Solomon stron- 
 
 tianite deposits east end of Mud Hills, San Bernar- 
 dino County, California 35 
 
 ABSTRACT 
 
 The Solomon and Ross strontianite deposits, about half a mile 
 art, are in the east end of the Mud Hills, northeast of Barstow, 
 '.lifornia, in the extreme southeast corner of the Searles Lake 
 adrangle. 
 
 The strontianite occurs as bedlike and crosscutting bodies that 
 alaced clays and tuffs that have been generally referred to as the 
 >samond series. At the Solomon deposit two principal zones 
 out 10 and 25 feet thick, separated by about 20 feet of barren 
 ly, contain most of the strontianite. At the Ross deposit numerous 
 dular and lenticular beds of strontianite are distributed vertically 
 •ough 186 feet of green clay. The strontianite-bearing zone of the 
 >ss deposit is 465 feet higher in the stratigraphic section than 
 it of the Solomon deposit. 
 
 The Solomon deposit, which was first worked in 1917, yielded a 
 all production at that time and has been inactive since. In 
 ent years small amounts of strontianite have been mined from 
 ! Ross deposit. 
 
 INTRODUCTION 
 
 The Solomon and Ross strontianite deposits described 
 this report are in the Mud Hills, which comprise the 
 
 ;?ond range north of the town of Barstow and are in 
 e extreme southeast corner of the Searles Lake quad- 
 ngle (1:250,000), at an altitude between 3,000 and 
 )00 feet (fig. 8). The northern part of the hills is com- 
 sed of granitic rocks; the southern part consists of 
 ■rtiary tuffs and lacustrine and fluviatile sediments that 
 a folded into an east-trending trough which has been 
 
 ' 'led the Barstow syncline. The lacustrine clays and ben- 
 
 •ublication authorized by the Director, U. S. Geological Survey. 
 Manuscript submitted for publication January 1953. 
 
 tonites in the trough of the syncline are readily converted 
 to slippery mud by even slight rains, a fact that probably 
 accounts for the name of the hills. The region is arid and 
 is sparsely covered with desert shrubs and Joshua trees. 
 No flowing streams or springs are present either within 
 the Mud Hills or in nearby areas. 
 
 The Solomon strontianite deposit is in sec. 20, T. 11 N., 
 R. 1 W., S. B., at an altitude of 3,200 to 3,400 feet, on the 
 north limb of the Barstow syncline. A fair dirt road leads 
 from the paved highway to the east end of the deposit. The 
 Ross strontianite deposit is half a mile to the southwest in 
 the NWi sec. 30, T. 11 N., R, 1 W., S. B., on the south limb 
 of the syncline. The Ross deposit, between 3,050 and 3,100 
 feet in altitude, is reached by a dirt road leading north- 
 ward from a graded but unpaved road that traverses the 
 valley south of the hills and that branches westward from 
 the paved road a little south of the valley trough. 
 
 History of the Area. Strontianite was discovered in 
 the Mud Hills in 1915 by Henry Hart and T. G. Nicklin. 
 Soon thereafter the deposits were examined by Adolph 
 Knopf (1918) who prepared a report that includes a sum- 
 mary of the early history of the area. A few additional 
 historical facts of interest that have become known to the 
 present writer are added here. 
 
 Knopf recorded the output of strontianite rock in 1917 
 as 500 tons. Lubin J. Henderson of Barstow, who is one 
 of the original claimants, told the writer that he and T. G. 
 Nicklin shipped ' ' several tons ' ' of carefully hand-picked 
 
 R2W 
 
 ri w 
 
 tun 
 
 TION 
 
 T9N 
 
 Figure 8. Map showing location of the Solomon and 
 Ross strontianite deposits. 
 
 (23) 
 
24 
 
 Special Report 32 
 
 material that ran 84.32 percent strontium carbonate. 
 Earl T. Ross, research chemist for the Stauffer Chemical 
 Company, Los Angeles, who is the present owner of the 
 Ross strontianite deposit, states that a shipment was made 
 at about that time to the Rare Metals Refining Company 
 of Pasadena, California, by whom he was then employed. 
 The strontianite was refined into strontium salts and 
 presumably was marketed. 
 
 Henderson and Nicklin then sold their claims to 
 Thomas J. Neilan of San Francisco, who, according to 
 Mr. Henderson, shipped 16 carloads of strontianite rock 
 to a plant near San Francisco, where it was dumped be- 
 cause it was of too low grade. 
 
 About 1920 the claims were sold to Mr. C. Solomon, 
 Jr., of San Francisco, who patented them in 1923 and who 
 is the present owner. 
 
 The production noted above is believed to have come 
 entirely from section 20 and therefore from the area des- 
 ignated in this report as the Solomon deposit. This is af- 
 firmed by Mr. Ross, and the writer has seen no cuts or 
 excavations of any size outside of that area. There has 
 apparently been no more recent production from the 
 Solomon deposit. 
 
 Knopf (1918, p. 260) referred to the strontianite in 
 the sediments of the south limb of the Barstow syncline 
 and spoke of this as the western part of the area. Probably 
 this is the area herein called the Ross deposit, owned by 
 Earl T. Ross. No other record has been found concern- 
 ing this deposit prior to its rediscovery by Ross. Though 
 it is the lesser deposit, it is the one from which production 
 has recently been made. At intervals Mr. Ross extracts 
 strontianite rock, which he converts and markets as 
 chemically pure strontium hydrate. 
 
 The locations and names of claims are shown on figure 
 12. No significant amounts of strontianite are known out- 
 side of these two deposits near the eastern end of Mud 
 Hills, though small amounts are found elsewhere in the 
 vicinity. According to Mr. Henderson, strontianite has 
 also been found in the area of granitic rocks in the north- 
 ern part of the Mud Hills. 
 
 No geologic work more recent than that of Knopf has 
 been done on the area, though brief mention of the de- 
 posits is made in several reports of the California State 
 Division of Mines on the Mineral Resources of San Ber- 
 nardino County (Tucker and Sampson, 1930, p. 323; 
 1943. p. 543) and in a chapter on strontium minerals by 
 B. N. Moore in a U. S. Geological Survey report on the 
 mineral resources of the region around Boulder Dam 
 (Hewett et al., 1936, p. 160). 
 
 The present project was a part of the IT. S. Geological 
 Survey's World War II program for the investigation of 
 strategic minerals. The field work was done in 1945. 
 
 Acknowledgments. The writer is indebted to Mr. 
 Lubin J. Henderson, of Barstow, California, for informa- 
 tion on the early history of the deposits. Mr. C. Solomon, 
 Jr., of San Francisco, kindly supplied information con- 
 cerning his property and gave his permission to study 
 the deposit and to publish the data resulting from the 
 study. Mr. Earl T. Ross gave much information about the 
 history of the area. He furnished nine partial chemical 
 analyses of strontianite rock presented in this report as 
 well as an outline map summarizing his knowledge of the 
 area ; he gave his permission to publish all the data. The 
 
 writer is grateful to these persons for their assistance 
 The author was assisted in the field and in the preparatior 
 of the maps by Mr. A. Cowles Daley. 
 
 GEOLOGY OF THE MUD HILLS 
 
 Stratigraphy. The northern half of the Mud Hills i: : 
 composed of granitic rocks of indefinite but certainly pre 
 Tertiary age. The southern half of the hills is composec 
 of relatively soft and easily eroded tuffs and lacustrim 
 sediments of Tertiary age, which have been folded into ; 
 complex east-trending structure generally known as th 
 Barstow syncline. The sediments of the central and south 
 ern portions of the syncline were beveled by erosion am 
 covered by alluvial deposits of Pleistocene or Recent age 
 Later an elevation of the range, or, conversely, a lowerin) 
 of base level, resulted in the cutting of new canyons int< 
 the Tertiary sediments, which are generally separate* 
 from one another by terrace remnants of the older al 
 luvial deposits. The lower courses of the main canyon 
 are flanked by extensive areas of colorful badlands. Th 
 headward parts of the stream canyons, which traverse th 
 somewhat more resistant and higher-standing basal tuff 
 and breccias, were incised at the same time to form vei 
 tical-walled gorges, some of which are barely passable o: 
 foot. 
 
 Vertebrate fossils in the higher beds of the section a 
 the west end of the Mud Hills were brought to the atten 
 tion of J. C. Merriam in 1911, who prepared a series o 
 papers on the remains. This work is summarized in 
 final paper by Merriam (1919). A geological reconnais 
 sance of the Mojave Desert region by C. L. Baker (191L 
 made in connection with the paleontological investigf 
 tions of Merriam, was published in 1911. This report cor 
 tains a large amount of information on the west and cer 
 tral parts of the Mud Hills and includes a cross sectio 
 but not a geologic map. 
 
 The Tertiary rocks of the Mud Hills, the higher bee 
 of which are upper Miocene (Merriam, 1919, p. 454) i 
 age, are generally known as the Rosamond series, a nan 
 first applied by Hershey (1902, pp. 349-372) to beds nee 
 Rosamond and Mojave, and extended to the Barstow svi 
 cline by Baker (1911, pp. 339-341). 
 
 Because of rapid changes in lithology, it has not bee 
 possible to correlate the stratigraphy at the east end < 
 the Mud Hills with that given by Baker for the west em 
 The writer has, therefore, measured his own stratigraph 
 sections at the east end of the hills near the strontiani 
 deposits. The lines of these sections are shown on figui 
 12 and the data are presented both as structure section 
 plate 3, and as columnar sections, plate 4. 
 
 The Tertiary rocks rest unconformably on the granit 
 rocks of the northern part of the hills. These Tertiar 
 rocks consist of 265 feet of thin-bedded tuff and clast 
 sediments at the base, which in turn are overlain co 
 formably by slightly more than 2,500 feet of rhyolite tu: 
 breccia and granitic breccia. The granitic breccia 
 mostly at the top in this section, but rapid changes tal 
 place along the strike, and great lenses of granitic bre 
 cia, scarcely distinguishable from granite in place, cor 
 and go in the tuff-breccia. There is scarcely any trace 
 bedding in this section, except for a rather persistent th 
 bed of sand and conglomerate at the base of the first thi 
 granitic breccia. 
 
Strontium Deposits, Southern California 
 
 25 
 
 In two places granitic breccia has been intruded by 
 ikes of dense, white rhyolite breccia. 
 
 A heavy conglomerate, composed almost exclusively of 
 Spite boulders, overlies the uppermost granitic breccia 
 id forms the uppermost unit of a thick sequence of 
 larse and almost unstratified sedimentary materials that 
 ,'e certainly of continental origin, probably lacustrine. 
 
 j The succeeding black-weathering algal limestone unit, 
 n feet thick, marks the beginning of a change to finer 
 astic sediments, although conglomerates are not absent 
 the higher beds. The limestone is overlain by 137 feet 
 ' dark-green and gray tuffaceous sandstone that include 
 ■ me conglomerate ; this sandstone is in turn overlain by 
 2- to 4-foot bed of white to gray calcareous rhyolite tuff. 
 ,bove the tuff is 25 feet of beds that are in part like the 
 nd beds below the tuff, but are also in places bright red 
 nd and shale. On the south limb of the syncline the red 
 •els are 65 feet thick (see sec. C-C, pi. 3). 
 
 The red beds are overlain on the north limb of the syn- 
 ine by about 120 feet of yellow and green clay, buff 
 arl, and white tuff, all of which are gypsiferous, and 
 ihich include the strontianite-bearing beds of the Solo- 
 on deposit (see sec. A- A' and B-B', pi. 3). The cor- 
 isponding lithologically similar beds on the south limb 
 the syncline south of the Ross deposit are 75 feet thick 
 eesec. C-C, pi. 3). 
 
 The succeeding beds form a highly varied sequence 
 out 1,300 feet thick composed predominantly of green 
 id buff clay, brown bentonite, white, yellow, and gray 
 
 *ff, and buff limestone, with some fine sandstone and 
 nglomerate at the base. The strontianite-bearing green 
 
 liy of the Ross deposit rests directly on the sandstone 
 
 . d conglomerate (see sec. C-C, pi. 3). 
 
 Algal nodules are common in the finer sediments, and 
 • lcareous concretions are found everywhere. The whole 
 i raence is gypsiferous ; the gypsum forms veinlets and 
 ilitary crystals but no beds. The lithology varies rapidly 
 ong the strike, as may be seen by comparing the strat- 
 i 'aphic section measured along cross section C-C with 
 
 at measured along cross section A- A', plate 3. The full 
 
 ickness of the sequence of finer clastic sediments that 
 1 gins at the base with the black-weathering algal lime- 
 j me is about 1,700 feet. All these finer sediments are of 
 1'ustrine origin. 
 
 The upper 450 feet along section A- A', plate 3, is com- 
 ]sed of yellow and brown poorly sorted and poorly con- 
 f idated cross-bedded sandstone, conglomeratic sand- 
 i»ne, and conglomerate. This sandstone and conglomer- 
 <i; sequence, which is probably fluviatile, seems to rest 
 ( lformably upon the underlying lacustrine beds. Per- 
 1 ps it represents fluviatile deposites on flood plains built 
 i on a filled lake basin, or deltaic material that was built 
 ( tward and above the lake level at the mouth of a large 
 fj jam. The top of this sequence is overlain unconform- 
 
 < ly by tilted alluvium. 
 
 Alluvium of two ages rests on the folded and eroded 
 1 Is of the Barstow syncline. The older alluvium, which 
 i "ms terraces between stream courses, rises from the level 
 
 < the present courses along the south edge of the hills 
 1 a height of 50 to 60 feet above them north of the axis 
 
 < the syncline. The older alluvium is designated on the 
 { )logic maps as terrace deposits of Quaternary age. 
 
 The younger alluvium is the present filling of the 
 stream channels and is designated as alluvium of Qua- 
 ternary age. 
 
 The alluvium of both ages consists mostly of gravels, 
 though sand, perhaps wind blown, is an abundant con- 
 stituent of the older alluvium. Windblown sand, not 
 separately mapped, occurs here and there over the whole 
 area. 
 
 Structure. The dominant structure of the Tertiary 
 sediments of the Mud Hills is the Barstow syncline, which 
 is complicated by minor folds and by oblique faults, the 
 general patterns of which are reflected on the geologic 
 map of the Solomon deposit, plate 5. The form of the 
 syncline near the east end of the hills is illustrated in the 
 accompanying structure section B-B', plate 3. The beds 
 of both limbs dip at moderate angles except near the base 
 on the north limb, where the dip is 75°. 
 
 Section C-C is effectively a continuation of section 
 B-B', though offset almost 2,000 feet to the west. Section 
 A- A', which extends slightly east of south from the east 
 end of the Solomon deposit, is separated from section 
 B-B' by a system of faults that presumably offset the 
 axis of the syncline east of section B-B' to the south. 
 Further complications exist, however, because the tuff- 
 breccia of the north limb is exposed just a little west of 
 the south end of section A-A', requiring that a fault of 
 several thousand feet displacement intervene in order 
 to bring these beds to the surface. 
 
 So far as is known, all faults except one in the Solomon 
 deposit are normal faults. Most faults strike northwest, 
 and dip both ways from the vertical. Their character can 
 often be determined by direct measurement of dip and 
 drag effects, which are usually well developed. 
 
 Igneous Activity. The period of deposition of the 
 sediments of the Barstow syncline was one of intense 
 igneous activity throughout the adjacent region. Baker 
 (1911, p. 342) described a basalt flow at the base of the 
 section on the south limb at the west end of the syncline. 
 Lavas and tuffs of equivalent age are abundantly repre- 
 sented in the Calico Mountains to the east. Sills of diabase 
 and syenite (?) are present at Lead Mountain a few 
 miles to the southeast. 
 
 The tuffs of the lower half of the section in the Barstow 
 syncline testify to the intensity of igneous activity in the 
 immediate vicinity. Rhyolite tuff in thin beds occurs 
 everywhere throughout the upper half of the section as 
 well, and probably the buff and green clay and the brown 
 bentonite are altered pyroelastic rocks. 
 
 The rhyolite breccia dikes found in the granitic breccia 
 are the only intrusive bodies seen in the Mud Hills area. 
 
 Hydrothermal Activity. Hydrothermal mineral de- 
 posits are only sparsely represented in the Mud Hills, 
 though they are abundant to the south and east. The 
 limestone near the south end of section A-A', plate 3, has 
 been largely replaced by dark-green, red, and brown 
 chalcedony, which has also replaced earlier-formed vein- 
 lets of barite, and shows excellent pseudomorphs. Re- 
 maining cavities are lined with small quartz crystals. 
 
 GEOLOGY OF THE SOLOMON STRONTIANITE 
 DEPOSIT 
 
 Stratigraphy. The strontianite rock of the Solomon 
 deposit is confined almost exclusively to two thin stron- 
 
26 
 
 Special Report 32 
 
 tianite-bearing beds that are separated by a clay shale 
 and limestone sequence. The map of the deposit, plate 5, 
 was extended beyond the outcrop limits of the stron- 
 tianite-bearing beds to include two persistent tuff hori- 
 zons that could be used as markers, one above and the 
 other below the strontianite. 
 
 The oldest beds within the area mapped consist of a 
 sequence of gray and green sandstone, pebbly sandstone, 
 and occasional thin conglomerate. Volcanic material con- 
 stitutes the major portion of these rocks. Pebbles and 
 cobbles of dense volcanic rocks are abundant in the con- 
 glomerate, and small pebbles of hornblende-bearing white 
 pumice are abundant in all the sandstone. Probably most 
 of the sand represents washed crystal-rich tuff. In the 
 lower part of this sandstone and conglomerate sequence 
 are several lenses of black- or dark-brown-weathering 
 algal limestone that are several hundred feet long and 
 1 to 2 feet thick. The base of the sandstone and conglom- 
 erate sequence, not shown on the map of the Solomon 
 deposit, rests on a 28-foot bed of algal limestone. The 
 limestone is replaced in part by dark-green to black chal- 
 cedony. 
 
 From 20 to 35 feet below the top of the sandstone and 
 conglomerate sequence there is a white, brown-weather- 
 ing calcareous rhyolite tuff that can be traced throughout 
 the area ; it is shown separately on the map. This bed, 2 
 to 4 feet thick, ranges in composition from quite pure 
 tuff to slightly tuffaceous limestone. 
 
 The sandstone above the tuff is generally finer than 
 that below, and conglomerates are absent above it. Green 
 clay beds that range in thickness from an inch to a foot are 
 present in some places, particularly in the more southerly 
 outcrops. At the western end of the deposit, notably on 
 the south limb of the anticline, which repeats the white 
 tuff bed, the upper 10 feet of the sandstone and conglom- 
 erate sequence consist of thin-bedded red sand grading 
 upward into clayey sand and yellow sandy clay, and in- 
 cludes a yellow limestone bed about a foot thick. Where 
 this sequence is exposed in the crest of an anticline, as 
 shown near the center of the map, the uppermost beds are 
 composed of reddish clayey sand overlain by a massive 
 sandy yellow clay. Apparently the source of material lies 
 to the north, for the rocks are finer grained to the south. 
 The red sand near the top, however, is recognized on the 
 south limb of the Barstow syncline, and is shown on sec- 
 tion C-C, plate 3, south of the Ross deposit. 
 
 In the east-central part of the area mapped, at and near 
 the top of the sandstone and conglomerate sequence, a 
 part of the sandstone has been cemented by strontianite. 
 
 The tuffaceous sands are overlain conformably by the 
 lower strontianite-bearing beds, and the transition is 
 abrupt except in the west end of the area where the over- 
 lying sands are clayey. 
 
 The lower strontianite-bearing beds consist of very 
 thin-bedded laminated buff and green tuffaceous clay, thin 
 buff marl, and one or more thin hard white tuff beds that 
 are persistent and can be traced over the area but were 
 not separately mapped. 
 
 A detailed description of the lithology of the lower 
 strontianite beds is given below in the measured strati- 
 graphic sections 5 and 6. 
 
 The base of the lower strontianite-bearing beds is usu- 
 ally sharply defined, but the upper contact is indefinite. 
 The thickness ranges from 15 to 30 feet. 
 
 The lower strontianite-bearing beds are succeeded by 
 sequence of sediments consisting mostly of thinly lam 
 nated yellow to brown clay shale, in beds one-eighth inc 
 to 2 inches thick, which alternate with buff, white-weathei 
 ing limestone layers one-sixteenth to one inch and usuall 
 about one-eighth inch thick. Peculiar, sharply groove 
 helmet- or hat-shaped calcareous concretions up to a 
 inch in diameter are characteristic of this zone. A massh 
 green tuffaceous gypsiferous claystone 3 to 4 feet thic 
 caps the thin-bedded clay and limestone. Where weathere 
 slightly, the upper half of this bed is yellow green an 
 the lower half is bluish green. This persistent and chai 
 acteristic stratum can be recognized everywhere in th 
 area. 
 
 The green claystone of the clay shale and limeston 
 sequence is overlain by the upper strontianite-bearin 
 beds, which are similar to the lower strontianite-bearin 
 beds. The upper strontianite-bearing beds consist mostl 
 of thin-bedded finely laminated buff and green tuffaceoi 
 clay and buff marl. White tuff beds, less distinctive tha 
 those in the lower beds, are actually more abundant in tl: 
 section. Details of the upper beds are given in measure 
 sections 1, 2, 3, and 4, presented below. The upper lim 
 of the beds is somewhat indefinite. The thickness range 
 from 5 to 15 feet. 
 
 The upper strontianite-bearing beds are succeeded b 
 a thick sequence of sediments, the basal 5 to 15 feet ( 
 which consists of thin-bedded clay shale and limestor 
 exactly like that of the clay shale and limestone sequent 
 between the upper and lower strontianite beds, excej 
 that it lacks the peculiar concretions so characteristic ( 
 the intermediate beds. This basal unit is succeeded by 5 1 
 10 feet of beds that are like the upper strontianite-bearir 
 beds but contain only minute amounts of strontianit 
 These clay, tuff, and marl beds are overlain by a high! 
 varied group of beds that consist of buff and green cla; 
 tuff, fine silty sandstone alternating with green clay, bu 
 thin-bedded limestones, and discontinuous layers of alg. 
 nodules embedded in clay. The higher part of the sequent 
 is largely green silty sandstone with thin layers of gree 
 clay. 
 
 From 50 to 70 feet above the base of the upper stroi 
 tianite-bearing beds there is a distinctive gray tuff un 
 that is never more than 2 inches nor less than half z 
 inch thick. The tuff is dark bluish-gray, except for a fe 
 places where its high lime content gives it a brown colo 
 It is coarse grained in the lower part and fine grainc 
 above. The lower part contains abundant sharply hexa 
 onal fresh crystals of biotite. 
 
 Gypsum is more or less uniformly present in all of tl 
 fine-grained rocks associated with the strontianite-bearii 
 beds. It occurs not as discrete beds but as thin stringe 
 and veinlets and separate crystals in the lower and upp 
 strontianite-bearing beds, and in the shales between ar ! 
 overlying them. 
 
 Structure. The structure of the Solomon deposit 
 illustrated by the four structure sections shown on plate 
 The Solomon deposit is on the north limb of the Barsto 
 syncline and therefore is located in a generally sout 
 dipping series of rocks modified by small folds and 1 
 faults of small displacement. An anticline flanked on tl 
 north by a syncline extends east and west across the ar 
 
Strontium Deposits, Southern California 
 
 27 
 
 g£ 5). The sandstones below the lower strontianite- 
 ■aring beds are exposed in six places along the crest of 
 :ie anticline. The disposition of these exposures shows that 
 ie anticline is not a simple fold but is a series of small 
 )mes, more or less en echelon. The dips are generally low 
 :cept on the northern flank of the anticline near the 
 iddle of the mapped area, where they are as much as 75°. 
 Many faults are shown on the map and structure sec- 
 ons, but all are small. The components of their displace- 
 ents in the direction of dip scarcely exceed 50 or 60 feet, 
 t addition to the faults shown, there are innumerable 
 laller faults with displacements ranging from a few 
 ches to 4 or 5 feet. While these faults do not materially 
 feet the disposition of the cartographic units, they do 
 live a bearing on the occurrence of strontianite as set 
 rth below. 
 
 Most of the faults are definitely normal faults; a few 
 Ttical faults probably originated in a similar manner, 
 ie one known exception is a reverse fault that extends 
 ost of the length of the deposit along the north flank of 
 e small syncline. Near the center of the mapped area 
 e fault dips as low as 26°, and here, where it is entirely 
 ithin the intermediate clays and thin limestones, it is 
 arked by a 4-foot zone in which the beds are extremely 
 ntorted. Similarly contorted beds are not found along 
 iy other fault in the area. The component of the dis- 
 acement on this reverse fault in the direction of the dip 
 the fault apparently is not more than 50 feet. 
 There is no direct evidence of the age of the reverse 
 : ult in respect to the normal faults. It is assumed to be 
 iier on the grounds that it probably resulted from the 
 impression that folded the beds, whereas the normal 
 : ults probably were formed by relaxation of compression 
 * completion of the folding. 
 
 Areal Extent of the Strontianite-Bearing Beds. So 
 :'r as in known, the two main strontianite-bearing tuf- 
 ;3eous clay beds, which are distinct stratigraphic units, 
 iatain important amounts of strontianite rock only in 
 i;3 mapped area. Both beds continue to the east beneath 
 iuvial deposits, and undoubtedly contain strontianite 
 i zk for some distance in that direction. At a distance of 
 i miles to the east, where lacustrine sediments again 
 (terge from beneath the alluvial cover, the lithology is 
 ( i erent, so that the strontianite-bearing beds, if repre- 
 iited, are not recognizable. The beds there contain no 
 I ontianite rock. 
 
 To the south the beds continue down dip for an un- 
 1 own distance. The strontianite-bearing beds are recog- 
 ) liable on the south limb of the Barstow syncline south of 
 ■! Ross deposit. They contain no strontianite there, 
 1 mgh very small amounts of strontianite may be present 
 {this horizon half a mile farther west. West of the Solo- 
 i n deposit, both the upper and lower strontianite-bear- 
 i; beds can be followed along the north limb of the 
 1 rstow syncline, and can be recognized in the trough of 
 ii syncline shown in section B-B', plate 3. Farther west 
 t ! beds are cut out by the large northwest-striking fault 
 I >wn on section B-B', plate 3, just south of the synclinal 
 £ s. The lower beds contain no strontianite beyond the 
 
 I -its of the geologically mapped area. The upper beds 
 c itain a small amount as far as the line of section B-B', 
 
 I I only in the most northern exposure, for in the trough 
 
 of the Barstow syncline, where the beds are well exposed, 
 no strontianite could be found. 
 
 The distance in an easterly direction over which stron- 
 tianite rock crops out is about a mile. How much farther 
 east and southward down the dip it may extend is un- 
 known. 
 
 The strontianite-bearing sandstones occur only in the 
 east-central part of the area. Because they are so re- 
 stricted and do not constitute a distinct stratigraphic 
 unit, they need no further consideration. 
 
 Abundance of Strontianite Bock. Six stratigraphic 
 sections, four across the upper strontianite-bearing beds 
 and two across the lower beds, were measured in order to 
 determine the amounts of strontianite rock contained in 
 them. These sections, which also give the detailed lithol- 
 ogy of the two beds, were chosen so as to be as repre- 
 sentative of the area as exposures and convenience would 
 permit. Their positions are indicated on the geologic 
 map, plate 5. 
 
 Section 1, Solomon strontianite deposit: upper strontianite beds. 
 
 Feet 
 
 Buff and light-green laminated clay 1.9 
 
 Buff marl 0.1 
 
 Buff and light-green laminated tuffaceous clay 0.3 
 
 Light-green massive tuff or tuffaceous clay 2.9 
 
 Buff and light-green laminated clay 0.9 
 
 Buff marl 0.2 
 
 Strontianite rock (has replaced buff clay) 0.4 
 
 Interbedded buff marl and brown clay 0.9 
 
 Brown claystone 0.25 
 
 Buff and light-green laminated clay 0.1 
 
 Strontianite rock (has replaced paper-thin laminated clay) 0.05 
 
 Buff and light-green laminated tuffaceous clay 1.0 
 
 Cream-colored thin-bedded tuff and tuffaceous clay 0.3 
 
 Buff and light-green laminated tuffaceous clay 1.3 
 
 Dark-green tuffaceous claystone 
 
 Total thickness 10.6 
 
 Total thickness of strontianite 0.45 
 
 Percent strontianite 4.2 
 
 Section 2, Solomon strontianite deposit: upper strontianite beds. 
 
 Feet 
 
 Light cream-colored nodular algal limestone 1.0 
 
 Buff to white laminated clay with laminae of cream to white 
 
 limestone 1.3 
 
 Strontianite rock (has replaced buff and light-green tuffaceous 
 
 clay and buff tuff) 1.3 
 
 Buff and light-green laminated clay 0.3 
 
 Light-green massive tuff or tuffaceous clay 2.5 
 
 Strontianite rock (has replaced buff tuffaceous clay and a few 
 
 thin stringers of marl) 1.2 
 
 Light-green massive clay 0.3 
 
 Buff marl 0.4 
 
 Light-green massive clay 0.2 
 
 Strontianite rock, and thin veinlets of celestite (has replaced 
 
 buff and light-green laminated tuffaceous clay and a few thin 
 
 stringers of marl) 0.6 
 
 Buff and light-green laminated tuffaceous clay and a few thin 
 
 streaks of marl 1.6 
 
 Gray to cream laminated calcareous tuff 0.4 
 
 Buff marl and tuffaceous marl 0.4 
 
 Buff and light-green laminated tuffaceous clay 1.2 
 
 Cream-colored laminated calcareous tuff 0.3 
 
 Dark-green massive claystone 
 
 Total thickness 13.0 
 
 Total thickness of strontianite 3.1 
 
 Percent strontianite 23.8 
 
28 
 
 Special Report 32 
 
 Section 3, Solomon strontianite deposit: upper strontianite beds. 
 
 Feet 
 
 Light-yellow sandstone 0.2 
 
 Buff to light-yellow sandy tuff 1.4 
 
 Light-green tuffaceous clay 0.4 
 
 Light-yellow sandy tuff 0.6 
 
 Light-green tuffaceous clay 0.4 
 
 Buff thin-bedded tuff 0.2 
 
 Light-green tuffaceous clay 0.9 
 
 Buff and light-green laminated clay 0.4 
 
 Buff and light-green laminated clay, probably partly replaced 
 
 by strontianite 0.5 
 
 Buff and pale-green laminated clay, buff to white tuff and buff 
 
 marl 0.8 
 
 Buff to yellow marl 0.6 
 
 Buff to light-green thin-bedded calcareous tuff 0.3 
 
 Strontianite rock (has replaced buff and green laminated clay) 0.3 
 
 Buff tuffaceous marl 0.4 
 
 Strontianite rock (has replaced buff and light-green laminated 
 
 clay) 0.2 
 
 Buff and light-green laminated clay, probably partly replaced 
 
 by strontianite 0.1 
 
 Strontianite rock (has replaced buff and light-green laminated 
 
 clay) 0.1 
 
 Buff to white thin-bedded tuff 0.3 
 
 Buff and light-green laminated tuffaceous clay 1.1 
 
 Dark-green tuffaceous claystone 
 
 Total thickness 9.2 
 
 Total thickness of strontianite 0.6 
 
 Percent strontianite 6.52 
 
 Section Jf, Solomon strontianite deposit: upper strontianite beds. 
 
 Feet 
 
 Light-green tuffaceous clay 1.0 
 
 Strontianite rock 0.5 
 
 Light-green tuffaceous clay 1.1 
 
 Strontianite rock and veinlets of celestite (has replaced marly 
 
 tuff) 0.6 
 
 Buff and light-green laminated tuffaceous clay with a few thin 
 
 stringers of marl 0.8 
 
 Strontianite rock (has replaced marly tuff) 0.3 
 
 Mostly green massive tuffaceous clay but contains a few thin 
 
 beds of buff and light-green laminated clay 4.2 
 
 Buff marly tuff 0.2 
 
 Buff and light-green laminated tuffaceous clay 2.3 
 
 Dark-green tuffaceous claystone 
 
 Total thickness 11.0 
 
 Total thickness of strontianite 1.4 
 
 Percent strontianite 12.7 
 
 Section J, Solomon strontianite deposit: lower strontianite beds. 
 Section 5a, upper part. 
 
 Feet 
 Buff and green laminated clay with few thin buff limestone 
 
 laminae 0.7 
 
 Buff and pale-green laminated clay with streaks of sand 1.9 
 
 Sandy tuffaceous green clay ; beds as much as 0.2 foot thick — 1.8 
 AVhite to buff tuffaceous clay in paper-thin laminae and thin 
 
 limestone laminae 0.7 
 
 Buff tuffaceous marl 0.2 
 
 Buff and green laminated tuffaceous clay 0.7 
 
 Strontianite rock and thin veinlets of celestite (has replaced 
 
 buff and light-green laminated tuffaceous clay) 1.0 
 
 AVhite to brown laminated tuffaceous clay with abundant 
 
 laminae of limestone and argillaceous limestone 5.1 
 
 Buff and light-green massive tuffaceous clay 1.9 
 
 Buff and light-green laminated tuffaceous clay 0.9 
 
 Light-green massive tuffaceous clay 1.45 
 
 White biotite-bearing tuff 0.05 
 
 Total thickness 16.4 
 
 Total thickness of strontianite 1.0 
 
 Percent strontianite 6.1 
 
 Section ob, loner part. 
 
 White biotite-bearing tuff 
 
 Light-green massive tuffaceous clay 
 
 Buff and brown massive silty clay 
 
 Buff tuffaceous marl 
 
 Massive to laminated buff tuffaceous clav 
 
 Buff marl 
 
 Buff massive tuffaceous clay 
 
 Buff laminated tuffaceous clay 
 
 Buff massive tuffaceous clay 
 
 Gray and buff laminated clay and silty clay and veinlets of 
 celestite parallel to bedding; three bands each one-fourth 
 inch thick probably contain some strontianite ; this zone 
 
 carries strontianite at other places 
 
 Buff and green laminated tuffaceous clay ; probably contains 
 
 some strontianite 
 
 Buff and brown laminated to massive tuffaceous clay 
 
 Fine green silty clay 
 
 Fine-grained reddish-brown silty sandstone 
 
 Fe 
 
 CL : 
 l.i 
 O.J 
 2.: 
 o.: 
 
 0.( 
 4.1 
 
 0.- 
 
 Total thickness 13.j 
 
 Total thickness of strontianite 0.1 
 
 Percent strontianite 0.0 
 
 Total thickness of lower beds, sections 5a and 5b com- 
 bined 30.: 
 
 Percent strontianite for lower beds, sec- 
 tions 5a <ind 5b combined 3.3 
 
 Section G. Solomon strontianite deposit: loirer strontianite 
 
 Buff, yellow, and light-green laminated clay with abundant 
 
 laminae of buff and white limestone 
 
 Strontianite rock (has replaced buff and light-green tuffaceous 
 
 clay) 
 
 Buff and light-green laminated tuffaceous clay with some 
 
 limestone laminae and streaks of marl 
 
 Strontianite rock (has replaced buff and light-green laminated 
 
 tuffaceous clay) 
 
 Buff and light-green laminated tuffaceous clay 
 
 Light-green massive clay 
 
 White biotite-bearing tuff 
 
 Light-green massive clay 
 
 Gray to buff laminated tuffaceous clay 
 
 Strontianite rock (has replaced yellow laminated tuffaceous 
 
 clay) 
 
 Yellow laminated tuffaceous clay 
 
 Strontianite rock and veinlets of celestite (has replaced yel- 
 low laminated clay) 
 
 Yellow to gray-green laminated tuffaceous clay 
 
 Strontianite rock (has replaced yellow laminated clay) 
 
 Yellow laminated micaceous clay 
 
 Brown massive algal limestone 
 
 bedt 
 Fe 
 
 Total thickness 23. 
 
 Total thickness of strontianite 2. 
 
 Percent of strontianite 8.4 
 
 The percentage of strontianite rook ranges from 
 23.8 percent. Section 2, from which the maximum val 
 was obtained, was chosen because it represents the ric 
 est section in the area. As the volumetric percentage 
 strontianite rock is the same as the linear percentage 
 the sections, provided the distribution is uniform, whi 
 is true for small volumes, the values obtained from t| 
 sections have been used in estimating the amount 
 strontianite rock in all sufficiently exposed areas (pi. r i 
 
 The amount of strontianite is indicated on plate 7 
 four groups of volumetric percentage ranges (group 1 
 contains up to 2.5 percent strontianite ; group 1 contaii 
 2.5-7.5 percent strontianite ; group 2 contains 7.5-15 p<- 
 cent strontianite; and group 3 contains 15-25 perce; 
 strontianite ) . Areas where exposure was so poor that i 
 estimation was not justified are indicated by a questii 
 mark. Of 466,700 square feet of map area of outcrop, <• 
 
Strontium Deposits, Southern California 
 
 29 
 
 cisive of those areas marked with a question mark, 24.0 
 [L'cent is in group ; 42.3 percent is in group 1 ; 28.6 
 rrcent is in group 2 ; and 5.1 percent is in group 3. The 
 e imated average grade of the total area is 6.4 percent, 
 d exclusive of group 0, 7.9 percent. 
 
 A more or less systematic variation in content of stron- 
 t nite rock is evident from the map. Strontianite rock is 
 n st abundant in the northern half of the area ; it is rare 
 tibsent (generally less than 1 percent) in the southwest- 
 hi part of the area. In the upper beds it is less abundant 
 i ag the southern margin in the central and eastern part 
 d the area than it is to the north ; the highest concentra- 
 m is present in the synclinal area near the northern 
 li it of the deposit. 
 
 I ['he strontianite content of the lower beds is more uni- 
 Im, but the only areas within them that fall in group 3 
 i in the northern part of the mapped area. The stron- 
 ;i lite-bearing sandstone is also along the northern flank 
 ) ;he previously mentioned synclinal area. 
 
 lie highest concentration of strontianite rock is close 
 ;< ;he reverse fault north of the synclinal axis. The pos- 
 ii e significance of this relationship is discussed later. 
 
 n view of the general decrease in amount of stron- 
 iiite rock toward the south, and the absence of strontia- 
 tt! rock beyond the limits of the mapped area to the west 
 U southwest, it is believed that the strontianite content 
 I'm dip in the central and eastern part of the deposit 
 c'th of the present limit of outcrop probably decreases 
 cidly. 
 
 extural and Structural Characteristics and Relation- 
 hs of the Strontianite Rock. The strontianite rock 
 st two forms that differ radically in field appearance, 
 itie of the strontianite rock is megaseopically fibrous 
 Im fibers from a small fraction of an inch to 3 inches 
 Wf. It is light to dark brown on both the fresh and the 
 Fathered surfaces. The second type, which is by far the 
 ie abundant, is a dense, fine-grained rock ranging 
 r l dark to very light brown when fresh and weathering 
 o'hite or light gray. Knopf (1918, p. 259) refers to gray 
 r rab strontianite rock, which is the appearance of the 
 p thered surface, but the writer has found none that is 
 c brownish when freshly broken. 
 
 a the weathered surface much of this dense strontia- 
 i rock shows small rounded spots that are whiter than 
 b intervening material. These are the microspherulites 
 eribed by Knopf. The present writer has made no 
 ii oscopic study of the material, but it seems likely that 
 11 f the dense strontianite rock is microspherulitic. Bed- 
 ii; planes show both on the weathered and on the fresh 
 Haees. Much of the material contains crystals of quartz, 
 sl'-par, and other detritus, which commonly show 
 r.| ed bedding resulting from deposition by water in 
 icon. 
 
 any bodies of strontianite have been traced to their 
 M , where the bedding is seen to be continuous with that 
 f |.e nonstrontianite-bearing rock beyond. Most of the 
 H daries of the strontianite rock against the nonstron- 
 late rock are very sharp, like the boundaries of ordi- 
 i concretions. These features leave little doubt that 
 H trontianite has replaced rocks of other composition, 
 indicated in the detailed sections given above, the 
 BJ tianite rock has replaced mostly the buff and green 
 m lated tuffaceous clay. Tuff has likewise been replaced, 
 
 and tuffaceous marl was the host in one place. Elsewhere 
 in a few places marl has been replaced, but in general 
 the calcareous rocks were avoided, as is shown in meas- 
 ured sections 1 to 6 above by the frequent appearances of 
 marl adjacent to strontianite rock that has replaced tuf- 
 faceous clay. 
 
 In figure 9 strontianite rock is shown in contact with 
 marl, having replaced tuffaceous clay beneath the marl. 
 In many places strontianite rock that has replaced tuf- 
 faceous clay is in contact with porous algal nodules that 
 have not been affected. 
 
 The dense strontianite is everywhere concretionary in 
 a broad sense of the word. It forms nearly spherical con- 
 cretions, elongated, bar- or rod-shaped concretions, and 
 stratiform bodies that are only greatly extended concre- 
 tions. Single strontianite "beds" vary in thickness from 
 a small fraction of an inch to a foot. Some of them can be 
 traced along the strike for scores of feet but eventually 
 they terminate abruptly. A single stratum in the lower 
 strontianite-bearing beds is probably traceable over most 
 of the area. This stratum, in most places about a foot 
 thick, is discontinuous, and the gaps are a foot to 50 feet 
 wide. It consists partly of huge pancake-shaped concre- 
 tions 4 to 10 feet in diameter. Unreplaced thin-bedded 
 laminated buff and green tuffaceous clays remain between 
 the strontianite rock lenses and the bedding and lamina- 
 tion can be traced through the strontianite rock (see figs. 
 9, 10, and 11). 
 
 Other bodies of the dense strontianite rock show cross- 
 cutting relationships, always related to either a fault or a 
 joint. Bedded masses cross abruptly through the bedding 
 along a fault and continue at a different horizon, as shown 
 in figure lie. More or less equidimensional concretions 
 and bar- or rod-shaped concretions are localized along 
 faults that usually have a displacement of only an inch 
 or two (fig. 11a and b). Along larger faults masses of 
 strontianite 2 feet thick and as much as 40 feet long have 
 replaced the rock on both sides (fig. lid). Intraforma- 
 tional brecciation structures, and tectonic breccia struc- 
 tures along faults, as shown in figure lie, are also present, 
 though the original rocks have been completely replaced. 
 Figure 10 shows, on a very small scale, a detail of the re- 
 lationship of a crosscutting body of strontianite rock that 
 merges into a bed. The discordant portion did not here 
 follow the fault, which is the more usual type, as shown 
 diagrammatically in figure lie and lid, but it is clearly 
 localized by the fault. In many places the strontianite 
 rock has replaced clay on only one side of a fault, and the 
 strontianite is molded against a slickensided surface on 
 the other. The author concludes that the present position 
 of all the strontianite rock is controlled by the replace- 
 ment mostly of tuff and tuffaceous clay under the control 
 of faults and joints, which are, of course, post-sedimen- 
 tary structures. 
 
 The megaseopically fibrous brown strontianite, much 
 less abundant than the lithoidal type, seems to have 
 formed upon the dense, fine-grained rock (fig. lid) and 
 is therefore the younger of the two. It was this fibrous 
 material that was sought in the early days of exploitation 
 of the deposit. The early production, judging by the evi- 
 dence of cuts, was obtained from the areas of the lower 
 strontianite-bearing beds immediately west and a little 
 south of the end of the road, and from the upper stron- 
 tianite beds east and south of this. Much of it probably 
 
30 
 
 Special Report 32 
 
 E X PLANATION 
 
 Strontionite rock 
 
 Mori 
 
 Thin-bedded buff and green tuffaceous cloy 
 
 Joints 
 
 3FEET 
 
 Figure 9. Detail of strontianite-rock lens. 
 
 Buff tuffaceous clay 
 
 Fault 
 Vi 
 
 Figure 10. Detail of strontianite rock transgressing bedding. 
 
Strontium Deposits, Southern California 
 
 31 
 
 EXPLANATION 
 
 phericol concretion localized by fault. Size range is 2 inches to I 
 oot in diometer. Displacement of fault is only a few inches 
 
 Ellar-shoped concretion in cross section. Observed cross sectional 
 ire 2 to 6 inches. Length of bars up to 4 feet. 
 
 C'trontiamte rock "bed" with tr ansgressive phose localized by fault. 
 n on observed occurrence the strontiamte rock is o foot thick. The 
 ransgressive phase is 4 feet long and con be traced along strike 
 if fault for obout 6 feet. 
 
 obular strontionite rock body in fault with connected "bed" ond central 
 ocket of coorse fibrous strontionite. Transgressive bodies of this 
 narocter ore os much os 2 feet thick and 40 feet long. 
 
 ;ontinuation in depth not known but observed in excess of 10 feet. 
 
 1 ;re 11. Diagrams showing strontianite rock localized by faults. 
 
 lie from the fault between the two beds located about 
 11 feet west of the end of the road. The clay is so sus- 
 Htible to wetting that the old cuts are all closed now and 
 1 surface is armored by 1 to 4 feet of weathered clay. 
 Llle strontianite can be seen in place, and most of the 
 il dus material found was float remaining from the old 
 I :ations. However, fibrous material in small amounts 
 J. found in place elsewhere. 
 
 he fibers of strontianite, mostly dark brown but in 
 p] es very light brown, form divergent bundles that 
 ?i v out from a base of the dense strontianite rock. Re- 
 naming outer surfaces are botryoidal. This fibrous mate- 
 I evidently developed for the most part in open cavi- 
 I and the terminations in open cavities are sharp 
 ■its of needlelike crystals of strontianite. Most of the 
 a ties were entirely filled. The fibrous material is thus 
 I sed in a shell of the dense material, and is in part in 
 i ick part of a bedded mass, but more often in a cross- 
 1 ing body along a fault as shown in figure lid. The 
 ■ >us strontianite thereby forms irregular veinlike 
 m^ .es within the dense strontianite rock. 
 
 mong the pieces of fibrous float found near the east 
 I of the body are some pieces that contain crystals of 
 in tz and feldspar, indicating that this material may 
 m resulted from the recrystallization of the dense ma- 
 iei 1 that had previously replaced tuffs. In any case it 
 9ft s clear that the long fibrous material is later than the 
 'le e variety. At several places near the west end of the 
 le sit, final cavities remaining between the spherules of 
 
 fibrous strontianite have been filled with grayish-brown 
 chalcedony. 
 
 Celestite in small amounts is present throughout the 
 deposit. It is easily recognizable by its white color and 
 slender tapering crystals with a rhombic cross section. 
 Crude crystals form matlike masses a millimeter or two 
 thick parallel to the bedding of the clay. Many portions 
 of the strontianite rock that are porous show minute but 
 perfect and brilliant crystals. In the concretionary bodies 
 of strontianite rock controlled by faults, there are in 
 nearly all cases thin veinlets of celestite in the actual fault 
 surfaces. The amount of celestite is never large, probably 
 never more than 5 percent of the strontianite rock, and 
 more usually only about 1 percent. Celestite is slightly 
 more abundant in the lower horizon than in the upper. 
 
 Knopf (1918, p. 264) thought that the celestite was 
 probably secondary, produced by reaction of the stron- 
 tianite with calcium sulfate solutions formed by surface 
 water and the ubiquitous gypsum. The present writer 
 agrees with this view except for the celestite that fills the 
 faults along which the strontianite rock replaced the tuff- 
 aceous clay. This celestite is perhaps primary in the same 
 sense as the strontianite, though it is younger. 
 
 Chemical Composition of the Strontianite Bock. It 
 has been shown that the strontianite rock was formed by 
 the replacement of other rocks ; much of it is impure be- 
 cause the replacement was incomplete. Grains of quartz 
 and feldspar and fragments of other minerals and rocks 
 are megascopically evident in most of it. Knopf (1918, p. 
 261) reported that strontianite is never pure SrCC>3, but 
 always contains CaC0 3 isomorphously. A carefully se- 
 lected sample collected by Knopf, probably near the east 
 end of the Solomon deposit (table 1), contains 10.25 per- 
 cent CaCOs in solid solution. 
 
 The available analyses of material from the Solomon 
 deposit are given in table 1 below. Analyses I and II are 
 by R. C. Wells, from U. S. Geological Survey Bulletin 
 660. Analyses III to VIII are by Earl T. Ross, research 
 chemist for the Stauffer Chemical Company, Los An- 
 geles, California, and owner of the Ross strontianite de- 
 posit, and were made available by him. 
 
 Analysis I represents a selected specimen of stron- 
 tianite. Analyses II to VII are of strontianite rock. An- 
 alysis VIII is obviously of a limestone and need not be 
 considered further. Though the exact locality of the sam- 
 ples is not known, the analyzed specimens probably are 
 quite representative of the deposit. 
 
 The analyses indicate that materials other than the 
 carbonates of strontium and calcium generally constitute 
 from 5 to 20 percent of the samples and average about 
 13 percent. The author's observations in the field con- 
 firm a value of this magnitude. Strontium carbonate con- 
 tent ranges from 59 to 87 percent and averages about 73 
 percent. The ratio of the weight of calcium carbonate to 
 strontium carbonate averages 0.18, and for the most 
 part, is probably less than 0.2 in most of the material 
 that is considered as strontianite rock. 
 
 Material other than the two carbonates includes celes- 
 tite, gypsum, quartz, feldspar, and fragments of other 
 rocks and minerals insoluble in cold acid. It is the au- 
 thor's opinion, based solely on field observation, that the 
 amount of celestite does not ordinarily exceed 5 percent 
 of the rock, and is probably generally less than 1 percent. 
 
32 
 
 
 
 Special Report 32 
 
 Table 1. Analyses of stroniianite rock. 
 
 
 
 
 
 I 
 
 II 
 
 Ill 
 
 IV 
 
 V 
 
 VI 
 
 VII 
 
 VIII 
 
 Averages 
 II-V 
 
 SrO 
 
 60.99 
 6.40 
 
 None 
 
 29.86 
 
 (computed) 
 
 0.05 
 
 55.20 
 5.19 
 
 None 
 28.18 
 
 0.28 
 5.59 
 1.17 
 
 59.51 
 20.91 
 19.58 
 
 82.51 
 
 12.32 
 
 5.16 
 
 71.08 
 14.05 
 
 14.87 
 
 87.. 
 13_. 
 n.d. 
 
 84.0 
 16.0 
 
 n.d. 
 
 1.5 
 98.5 
 n.d. 
 
 
 CaO 
 
 
 BaO . . 
 
 
 COj - - 
 
 
 SOj . . 
 
 
 Si02.-- - . - 
 
 
 Al-Ch 
 
 
 
 
 SrC0 3 . ._. . 
 
 97.30 
 
 87. 
 10.2.3 
 
 95.61 
 
 78.6 
 9.3 
 
 12.1 
 
 73 
 
 CaCOj 
 
 14 
 
 
 13 
 
 
 
 CaCO. 
 
 97.25 
 0.118 
 
 100.0 
 0.118 
 
 100.00 
 0.352 
 
 99.99 
 0.149 
 
 100.00 
 0.198 
 
 100 
 0.15 
 
 100.0 
 0.19 
 
 100.0 
 
 0.18 
 
 SrCOj 
 
 I. Strontianite, selected sample. [Probably from a locality near the east end of the 
 
 Solomon deposit.] Analyst, R. C. Wells, U.S.G.S. Bull. 660, p. 262. 
 II. Faintly banded aphanitic rock resembling a drab limestone [strontianite rock]. 
 Under microscope is seen to be composed of extremely small obscure spherulites of 
 strontianite. Analyst, R. C. Wells, U.S.G.S. Bull. 660, p. 260. [Probably from 
 the Solomon deposit.] 
 
 III. Hard brown strontianite rock. East end of Solomon deposit, north of road [east of 
 
 wash?]. Analyst, Earl T. Ross. 
 
 IV. Brown crystalline strontianite rock, outcrop 25 feet long, 3 feet thick. Near west 
 
 end of Solomon deposit. Analyst, Earl T. Ross. 
 
 The greater part of the insoluble materials is represented 
 by common rock-forming minerals not replaced by car- 
 bonates. The amount of unreplaced clay is unknown but 
 is probably variable and not very large. It must repre- 
 sent only a small part of the noncarbonate fraction. 
 
 Possible Origins of the Strontianite Rock. Knopf 
 (1918, p. 264), in his brief report on this area says, "at 
 first glance the appearance of the layers of gray sphe- 
 rulitic strontianite suggests that they are beds of stron- 
 tianite that were deposited as chemical precipitates from 
 the lake in which the gypsiferous clays were laid down. 
 ..." He then goes on to say that more probably the 
 strontianite rock originated by the replacement of lime- 
 stone, principally algal in origin, "doubtless by cold 
 meteoric water. ' ' He evidently believed that the stron- 
 tium carbonate was an original sedimentary constituent 
 of the rocks concentrated in the manner of formation of 
 ordinary concretions. 
 
 Undoubtedly the strontianite rock is replacement of 
 other rocks. This origin is indicated by the preservation 
 of pre-existing sedimentary and tectonic structures in 
 the strontianite rock, and by the relationships at the 
 boundaries of strontianite rock masses as previously de- 
 scribed. Knopf's choice of limestone as the pre-existing 
 rock was apparently determined by observation mostly at 
 the "western part of the field," probably the area now 
 called the Ross deposit. The present writer agrees that 
 this may be the relationship there. At the Solomon de- 
 posit, however, the principal replaced rock was the finely 
 laminated, thin-bedded tuffaceous clay. To a lesser ex- 
 tent tuff and tuffaceous marls were also replaced, but to 
 a marked degree the carbonate rocks were left untouched. 
 
 Pre-existing rocks were replaced by strontium car- 
 bonate, and the replacement followed the tectonic dis- 
 turbance of the sediments, for tectonic breccias and other 
 fault features are preserved in the strontianite rock. The 
 important question that remains is whether the stron- 
 
 V. Hard dense white ore [strontianite rock]. Outcrop 13 feet long, 2 feet thick. N 
 
 center of Solomon deposit. Analyst, Earl T. Ross. 
 VI. Light-brown granular crystalline ore [strontianite rock]. Near west end of Solor 
 deposit. Analyst, Earl T. Ross 
 VII. Heavy light-brown satiny ore [strontianite rock]. Selected, east end of Solor 
 deposit. [Probably from upper strontianite-bearing beds.] Analyst, Earl T. R> 
 VIII. Light-brown granular ore [limestone?]. Near west end of Solomon deposit. Anal 
 Earl T. Ross. 
 Notes in brackets are by the present author. 
 
 tium carbonate was an original constituent of the sec 
 ments or whether it was introduced in hydrotherni 
 solutions. No conclusive answer can be given as yet, b, 
 the second possibility is favored by the present writi 
 
 Favoring the view that the strontium carbonate ; 
 syngenetic with the sediments are the facts that the strc- 
 tianite rock is confined to a few thin and characteris: 
 stratigraphic units, and, except for the strontianite-be;- 
 ing sandstones, these units are lithologically simi!" 
 among themselves and lithologically distinct from i- 
 jacent nonstrontianitic beds. Furthermore, the strc- 
 tianite-bearing beds singly and in total are very thin i 
 relation to their areal extent. 
 
 Granting this origin of the strontium carbonate, ft 
 concentration may then be accepted as due to the sa? 
 circumstances by which concretionary bodies of calcin 
 carbonate are formed. Yet the source of the strontiu 
 in the lake waters remains a puzzle. It may, however, ha 
 been introduced as a constituent of volcanic materi, 
 which is a major component of the sediments both of I 
 strontianite-bearing and nonstrontianite-bearing pas 
 of the section, or it may have been carried into the la 
 in solution, having originated as a by-product of volcac 
 activity through gaseous exhalations or through spr z 
 waters partly of juvenile origin. A choice between the 
 possibilities cannot yet be made, but in any event I 
 strontium carbonate would then have been precipita 1 
 from the connate waters of the sediments in sucla 
 manner as to replace the previously deposited clay. 
 
 This hypothesis is supported by the occurrence of <? 
 sodium and calcium borates generally accepted as be 2 
 sedimentary in origin, in similar lake beds in other pa s 
 of the Mojave Desert region. By way of direct analo'. 
 concretions of strontium sulfate are present a few incs 
 beneath the surface of the Bristol Dry Lake, here a 
 there in an area of several square miles, where they t 1 
 presumably forming at the present time in gypsiferis 
 
Strontium Deposits, Southern California 
 
 :::; 
 
 ays immediately beneath the surface where deposition 
 i 3urrently taking place. There is, therefore, little reason 
 t object to the concept of sedimentary strontium car- 
 bate even though its original source may not be 
 kown. 
 
 On the other hand, several features of the deposit are 
 tt satisfactorily explained by this hypothesis. Chief 
 a ong them is the fact that the strontianite rock is con- 
 tiled in position by tectonic structures as well as by 
 3 limentary structures and is therefore younger than the 
 t tonic episode that disturbed the sediments. To explain 
 t s fact, either the precipitation of the strontium car- 
 tiate from solution was delayed until long after sedi- 
 r ntation or a part of the strontium carbonate was dis- 
 5 ved and re-precipitated under the control of joints and 
 f dts. Neither idea is easily credible. 
 
 Squally difficult to explain by the hypothesis of sedi- 
 lintary origin are: the general concentration of stronti- 
 a.te rock in the northern part of the area in association 
 via reverse fault, though it may be argued that this is 
 f tuitous ; the highly restricted occurrence of the stron- 
 t aite-bearing sandstones along the same fault ; and the 
 a lost total absence of strontianite from the beds above 
 ft upper strontianite-bearing beds which are othenvise 
 H ntical. 
 
 Similar indirect arguments must also be used in con- 
 s ering the possibility of a hydrothermal origin of the 
 cbosit, for direct evidences are lacking. 
 
 The post-tectonic age of the strontianite-rock bodies 
 a 1 the observed control of form and position exerted on 
 t m by tectonic structures are to be expected if the de- 
 pit is hydrothermal. The general concentration of stron- 
 t: lite rock along the northern edge of the deposit near 
 I reverse fault is easily explained if the fault is assumed 
 toe the fundamental channel for the upward migration 
 
 ihe solutions. The localization of the strontianite-bear- 
 ii sandstones in the vicinity of the reverse fault is har- 
 n aious, for their composition must have been favorable 
 £ replacement. The absence of strontianite from the bed 
 ave the upper beds may be due to the impoverishment 
 Oithe solutions through deposition in the strata below, 
 ^jtch were encountered first. 
 
 ''he marked stratiform character of much of the stron- 
 ti lite rock leads at once to the thought, as pointed out 
 b Knopf (1918, p. 264) that it is a chemical precipitate 
 film the lake. However, this is also harmonious with a 
 h Irothermal origin, for the beds are more accurately de- 
 si bed as concretions that have two dimensions vastly 
 g ater than the third. Their great lateral extent in the 
 b' ! s may be a result of the control of migration of stron- 
 tin-bearing solutions by bedding discontinuities, or of 
 tl; greater ease of replaceability of one bed over adjacent 
 b<s, or of a combination of these influences. 
 
 'he long fibrous botryoidal masses of strontianite 
 
 1 ned in cavities within the lithoidal variety, mostly in 
 I ordant bodies along faults, have a structure typical 
 I lydrothermal deposits. That some of the cavities are 
 fi 1 d by chalcedony is also to be expected of hydrother- 
 I solutions rather than connate waters. The presence of 
 c< stite as a last mineral in faults and joints that have 
 I trolled the position of strontianite concretions may 
 a- be explained if a change from carbonate to sulfate 
 S( tions is postulated toward the end of the episode. 
 
 This hypothesis of origin is further supported by hy- 
 drothermal deposits of barite and silica that are in the 
 immediate vicinity as well as in nearby ranges ; also, igne- 
 ous activity of appropriate age, from which hydrothermal 
 solutions might have been derived, has taken place 
 throughout the region. 
 
 The writer concludes that the weight of available evi- 
 dence seems to favor the hydrothermal theory of origin, 
 even though the sedimentary hypothesis satisfactorily ex- 
 plains many features of the deposit. 
 
 Economic Aspects of the Deposit. Most of the bodies 
 of strontianite rock are very small. The largest bodies are 
 no more than 2 feet thick, 40 feet long, possibly extend 40 
 feet in depth, and contain less than 300 tons of stronti- 
 anite rock. Bodies of such size are very feAv in number, but 
 there are many smaller bodies and the total amount of 
 strontianite in the deposit is fairly large. 
 
 In estimating the tonnage present, all areas of outcrop 
 were classified into one of four groups based on volume 
 percentage ranges, as shown on plate 7. The areas for 
 each percentage range were measured and an average per- 
 centage for each group was used in estimating the volume 
 of strontianite rock for a depth of 10 feet, In all calcula- 
 tions the strontianite rock was assumed to weigh 200 
 pounds per cubic foot. This weight corresponds to a spe- 
 cific gravity of 3.2, which is in agreement with rough 
 measurements made in the field, and with the average 
 composition of samples listed in table 1. The equivalent 
 amount of strontium carbonate is taken as 73 percent of 
 the strontianite rock, the average value obtained from 
 analyses II to V, table 1. 
 
 The total tonnage in bodies averaging 5 percent or 
 more of strontianite rock is estimated as at least 400,000 
 tons. This figure corresponds to about 290,000 tons of 
 strontium carbonate. These figures are conservative, for 
 in much of the lower beds the strontianite rock is in excess 
 of the average of 5 percent by volume, and considerable 
 parts of the upper bed contain more than an average of 
 10 percent by volume. Additional strontianite rock is 
 present in areas marked by question marks, where data 
 were not sufficient to permit an estimate. 
 
 The large expanse of the lower beds in the east-central 
 part of the mapped area (pi. 7) is probably one of the 
 richer parts of the material that was mined in the early 
 days. This area cannot be considered exhausted, for Mr. 
 Henderson asserted, and the workings show, that opera- 
 tions were nowhere carried to a depth greater than 8 feet. 
 Nevertheless, the greater part of the strontianite is so 
 distributed as to constitute less than 10 percent by volume 
 of the enclosing rock so that, except for very small areas 
 as indicated in the estimated content in outcrops, the 
 deposit as a whole is low grade. An additional small 
 amount of strontianite, not included in the tabulation 
 above, is in the strontianite-bearing sandstones. 
 
 A glance at the geologic map and cross sections (pis. 5 
 and 6) will show that the greater part of the strontianite- 
 bearing rock is buried beneath barren materials. The bulk 
 of the lower strontianite-bearing beds lies at depths of as 
 much as 50 feet. The richest parts of the upper stron- 
 tianite-bearing horizon, areas A and B, as shown on plate 
 7, are concealed beneath terrace gravels from 10 to 30 
 feet thick. This overburden would probably have to be 
 removed before mining of the strontianite rock could be 
 
34 Special 
 
 started. A conspicuous lack of sites for the disposal of 
 waste is an additional difficulty. 
 
 GEOLOGY OF THE ROSS STRONTIANITE DEPOSIT 
 
 Stratigraphy. The strontianite rock at the Ross de- 
 posit is confined to a green clay unit, the base of which is 
 about 465 feet higher in the section than the strontianite- 
 bearing beds of the Solomon deposit (see pis. 3 and 4). 
 The beds that contain strontianite rock at the Solomon 
 deposit come to the surface again south of the Ross de- 
 posit, where they consist of thin-bedded yellow and brown 
 clay with thin buff limestone layers from which stron- 
 tianite rock is absent. A part of the section contains a 
 few small peculiarly grooved calcareous concretions that 
 are characteristic of the clay shale and limestone sequence 
 between the upper and lower strontianite-bearing beds of 
 the Solomon deposit. 
 
 The 465 feet of beds overlying this unit consists of 
 alternating greenish-gray and brown sandstone and con- 
 glomerate with several thin blackish-brown algal lime- 
 stone beds near the middle. The uppermost 50 feet is a 
 sequence of light-yellow thin-bedded sandy tuffs alternat- 
 ing with fine brown sand and thin beds of green clay. 
 Green clay is more abundant toward the top, thus form- 
 ing a transition to the overlying clay unit that contains 
 the strontianite rock (see pi. 2). 
 
 The strontianite-bearing unit is a notably uniform 
 sequence of alternating thin-bedded green clay and stron- 
 tianite beds. Near the top there are a few lenses of buff 
 limestone 2 to 4 inches thick that weather dark reddish 
 brown. Dark-brown-weathering ellipsoidal concretions of 
 buff limestone are abundant. Most of these concretions 
 contain internal cracks and cavities that are lined with 
 dark-red-brown rhombohedrons of calcite. Details of the 
 section are given in the measured section 1 presented 
 below. 
 
 Immediately overlying the green clay-strontianite rock 
 sequence, and shown separately on the map, is a light-tan 
 to white porous calcareous tuff unit about 2 feet thick. 
 This unit in turn is succeeded by a highly varied sequence 
 of alternating beds of green and buff clay, light-colored 
 limestone beds 1 to 3 feet thick, and variously colored tuff 
 beds. Brown bentonite occurs near the top and forms a 
 transition to a massive brown bentonite unit above. 
 
 Unconformably overlying these beds are terrace grav- 
 els and alluvium. 
 
 Structure. The Tertiary sediments dip northward 
 from 20° to 50°. The strike of the beds changes from one 
 end of the deposit to the other, so as to form a slight flex- 
 ure on the north-dipping south limb of the Barstow 
 syncline. 
 
 A small normal fault forms the contact between the 
 green clay and underlying sand for several hundred feet 
 along the southwest margin of the deposit. Only three 
 other very minor faults were found. 
 
 Areal Extent of the Deposit. The exposed part of the 
 deposit is completely shown on the accompanying map, 
 plate 2. The strontianite-bearing beds thin and fade out 
 to the west, and are absent along the western margin 
 of the mapped area. About 1,000 feet farther west the 
 strontianite-bearing clay reappears from beneath the 
 alluvium, but no strontianite is present. At the east end 
 the strontianite-bearing clay containing abundant stron- 
 tianite passes beneath a cover of alluvium and is not 
 
 >ORT 32 
 
 Table 
 
 2. Analyt 
 
 es of strontianite rock 
 
 — Ross deposit. 
 
 
 I 
 
 II 
 
 III 
 
 IV 
 
 Average 
 I-IV 
 
 SrO 
 
 20.50 
 32.10 
 33.32 
 11.37 
 
 8.93 
 34 . 59 
 30.92 
 20.87 
 
 89.0 
 11.0 
 n.d. 
 
 79.0 
 21.0 
 n.d. 
 
 53 
 
 40 
 
 7 
 
 CaO 
 
 COz 
 
 
 
 SrCOj 
 
 CaCOs 
 
 97.29 
 
 29.23 
 57.35 
 11.37 
 
 95.31 
 
 12.70 
 61 . 85 
 20.87 
 
 
 CaCCh 
 
 97.95 
 1.96 
 
 95.42 
 
 4.87 
 
 100.0 
 0.12 
 
 100.0 
 0.27 
 
 1.80 
 
 SrCOa 
 
 I. Dense, brown, radially fibrous strontianite in trench 100 feet northwest of instru 
 
 station F. Analyst, J. G. Fairchild. 
 II. Light-brown porous strontianite rock at instrument station I. Analyst, J. G. Falrcl 
 
 III. Heavy, white, fine-grained ore. [From cut by instrument station F.] Analyst, 
 
 T. Ross: supplied by courtesy of Mr. Ross. 
 
 IV. Brown, radially fibrous ore. [From east end of deposit.] Analyst, Earl T. Ross; i 
 
 plied by courtesy of Mr. Ross. 
 
 Notes in brackets are by the present author. 
 
 again exposed at the surface. The eastern limit is then 
 fore unknown, and strontianite rock may continue fc 
 some distance. 
 
 The extent of strontianite rock in the direction of di 
 is likewise unknown, though its continuation in that d 
 rection is assumed to be several hundred feet. 
 
 Nature of the Strontianite Bock. The strontianite roc 
 is in short concretionary nodular beds that range froi 
 0.1 foot or less to 1.5 feet in thickness. Most beds ai 
 highly nodular and the thickness varies rapidly fro? 
 point to point. 
 
 Most of the strontianite rock is very porous so th< 
 both the weight and the apparent specific gravity ai 
 poor guides to the quality. The color ranges from near! 
 white to very dark reddish and blackish brown. A vei 
 fine spherulitic texture is widespread, and here and the: 
 may be found small amounts of fibrous spherulitic stro: 
 tianite with fibers as long as half an inch. The long' 
 fibers of strontianite form a lining of cavities, which al: 
 usually contain white needles of celestite and dark-re 
 dish-brown rhombohedrons of calcite. Bedding plan 
 are not evident within the strontianite rock, and nonca 
 bonate inclusions are not megascopically visible, thouj 
 there is possibly some clay. 
 
 Two partial analyses of the strontianite rock have be* 
 made available by Earl T. Ross, owner of the deposit, ai 
 two have been made by the U. S. Geological Survey. 
 
 These data are not satisfactory for the estimation 
 reserves, partly because the insoluble fractions were n 
 determined in the analyses supplied by Mr. Ross ai 
 partly because of the large variation in the ratio of SrO 
 to CaCOs. The content of the samples is variable b 
 some of the strontianite rock is quite high in SrC03. 
 
 Origin of the Strontianite Rock. Little can be se 
 at the Ross deposit that sheds any light on the origin 
 the deposit. There is no evidence of the control of t' 
 strontianite by tectonic structures as at the Solomon cj 
 posit. The strontianite layers are bedded ; that is to si. 
 they are parallel to the bedding planes of the enclosi: 
 green clay, though they show no internal bedding ft- 
 
Strontium Deposits, Southern California 
 
 35 
 
 Strontium No I 
 (potented) 
 
 Strontium No 2 
 {patented) 
 
 GEOLOGIC MAP 
 SOLOMON STRONTlANlTf 
 DEPOSIT 
 
 20 
 
 Old Home 
 (patented) 
 
 Geology by Cordell Durrell and AC. Ooley, December 1944 
 
 4000 6000 FEET 
 
 Figure 12. Location and claims map, Ross and Solomon strontianite deposits east end of Mud Hills, 
 
 San Bernardino County, California. 
 
36 
 
 Special Report 32 
 
 Section 1, Boss Strontianite deposit. 
 
 Feet 
 
 Calcareous tuff 2.0 
 
 Light-green laminated clay 60.6 
 
 Brown-weathering buff limestone 1.9 
 
 Green clay 3.0 
 
 Brown-weathering buff limestone 0.6 
 
 Green clay 3.5 
 
 Brown-weathering buff limestone 0.5 
 
 Green clay 3.3 
 
 Strontianite rock 0.2 
 
 Green clay 12.7 
 
 Brown-weathering buff limestone 0.3 
 
 Green clay 1.4 
 
 Strontianite rock 0.3 
 
 Green clay 0.2 
 
 Strontianite rock 0.1 
 
 Green clay 16.2 
 
 Strontianite rock 0.3 
 
 Green clay 7.0 
 
 Strontianite rock 0.9 
 
 Green clay 32.2 
 
 Strontianite rock 0.3 
 
 Green clay 7.6 
 
 Strontianite rock 0.3 
 
 Green clay 19.5 
 
 Strontianite rock 0.3 
 
 Green clay 1.4 
 
 Strontianite rock 0.1 
 
 Green clay 1 3.2 
 
 Strontianite rock 0.1 
 
 Green clay 20.2 
 
 Strontianite rock 0.3 
 
 Green clay 10.4 
 
 Strontianite rock 0.2 
 
 Green clay 15.2 
 
 Strontianite rock 0.4 
 
 Green clay 3.4 
 
 Strontianite rock 0.4 
 
 Green clay 8.2 
 
 Strontianite rock 0.1 
 
 Green clay 2.5 
 
 Strontianite rock 1.3 
 
 Green clay 1.6 
 
 Strontianite rock 0.5 
 
 Green clay 1.2 
 
 Strontianite rock 0.7 
 
 Green clay 4.5 
 
 Strontianite rock 0.5 
 
 Green clay 4.5 
 
 Strontianite rock 0.5 
 
 Green clay 1.8 
 
 Strontianite rock 0.1 
 
 Green clay 2.7 
 
 Strontianite rock 0.2 
 
 Green clay at top, grading downward into tuffaceous and 
 
 sandy sediments 49.7 
 
 Total thickness 311.1 
 
 Thickness from upper to lower strontianite beds 186.0 
 
 Thickness of strontianite rock 8.1 
 
 Percent of strontianite rock (of 186.0 feet) 4.4 
 
 tures. Very probably the strontianite has replaced pre- 
 existing rocks, though this replacement is inferred and 
 not demonstrated. 
 
 Knopf's opinion (1918, p. 264) was that the stronti- 
 anite had replaced limestone, particularly in what he 
 called the "western part of the area," which is presumed 
 to be the present Ross deposit. This limestone replace- 
 ment may be possible, for the similarity is marked 
 between the strontianite-bearing beds and the dark- 
 Aveathering buff limestone beds and concretions that are 
 also interbedded in the green clay. However, the lime- 
 stone beds are not nodular, and the concretions have 
 rather smooth surfaces. This difference from the stronti- 
 
 anite rock leads the present writer to the belief that ch 
 rather than limestone was the original rock. 
 
 The strontium in solution in the lake water probab" 
 did not originate by weathering of the rocks in the drai: 
 age basin. More probably it originated in igneous activii 
 and was carried into the lake with the tuffs that are : 
 abundant in the section, by way of volcanic emanatio 
 or by spring waters partly of juvenile origin. 
 
 If this hypothesis is correct, then the Ross and Solomr 
 deposits are independent of each other, for the latter 
 believed to have formed later, after the folding 
 faulting of the beds. On the other hand, no proof 
 known that the Ross deposit is not also hydrother 
 in origin, in which case the two deposits would probat 
 have been contemporaneous. 
 
 Reserves. The individual beds of strontianite 
 were separately mapped as far as exposures would 
 mit. The map (pi. 2), however, does not give a sat 
 factory picture of the quantity of strontianite rock, 
 probably only about half the extent of the beds is sho\ 
 
 The section presented below was taken near the cei 
 of the Ross area (see pi. 2). The location represents 
 most complete exposure available, and it probably co 
 tains an average number of beds. Much of the area ea 
 of the section undoubtedly contains somewhat mo 
 strontianite rock. 
 
 The section was taken across the full thickness of 
 green clay unit. Of the total thickness of 311.1 feet on 
 186.0 feet contains strontianite rock, for there are barr 
 zones at the top and bottom that are respectively 75.4 i 
 49.7 feet thick. Of the 186.0 feet, 8.1 feet, or 4.4 perce 
 is strontianite rock. 
 
 The exposed area containing strontianite rock is 294,0 
 square feet. Using the value of 4.4 percent as the fraet 
 of strontianite rock, and 200 pounds per cubic foot 
 the weight of strontianite rock, about 13,000 tons of str 
 tianite rock is present for each 10 feet of depth. A possi 
 additional 1,000 to 1,500 tons per 10 feet of depth is c 
 cealed beneath the terrace near the east end of the depo 
 Should the deposit continue down dip for 100 feet, 
 reserves would amount to around 140,000 tons of str 
 tianite rock. No certain value for the strontium carbon 
 content of the strontianite rock at the Ross deposit e 
 be established from the analyses. The average of the fo 
 analyses is 53 percent, but this figure may not be ai 
 where near a proper value. 
 
 REFERENCES 
 
 Baker, C. L. (1911), Notes on the later Cenozoic history of 
 
 Mojave Desert region in southeastern California : California Un 
 
 Dept. Geol. Sci. Bull. 6, pp. 333-383. 
 Hershey, O. H. (1902), Some Tertiary formations of southern C 
 
 forni'a : Am. Geologist, vol. 29, pp. 349-372. 
 Hewett, D. F., Moore, B. N., Callaghan. Eugene, Nolan, T. 
 
 Rubey, W. W., and Schaller, W. T. (1936), Mineral resourccsf 
 
 the region around Boulder Dam : U. S. Geol. Survey Bull. 8 
 
 197 pp. 
 Knopf, Adolph (1918). Strontianite deposits near Barstow, Cal : 
 
 U. S. Geol. Survey Bull. 660, pp. 257-270. 
 Merriam, J. C. (1919), Tertiary mammalian faunas of the Moj.e 
 
 Desert : California Univ., Dept. Geol. Sci. Bull. 11, pp. 438-585. 
 Tucker, W. B., and Sampson, R. J., 1930, Los Angeles field divisii: 
 
 California Jour. Mines and Geology, vol. 26. pp. 202-324. 
 Tucker, W. B., and Sampson, R. J. (1943), Mineral resources of fa 
 
 Bernardino County, California : California Jour. Mines and G - 
 
 ogy, vol. 39, pp. 427-549. 
 
CELESTITE DEPOSITS NEAR LUDLOW SAN BERNARDINO COUNTY, CALIFORNIA* 
 
 By Cordeix Durrell, 
 
 OUTLINE OF REPORT 
 
 Page 
 
 itraet 37 
 
 reduction . 37 
 
 ilogy 37 
 
 tratigraphy 38 
 
 Pre-Tertiary rocks 38 
 
 Tertiary rocks 38 
 
 Quaternary rocks 39 
 
 tructure 39 
 
 [ineral deposits 39 
 
 illogy of the celestite deposits 39 
 
 tratigraphy 40 
 
 Tertiary rocks 40 
 
 Quaternary rocks 41 
 
 tructure 41 
 
 iccurrence of celestite 41 
 
 hemical composition of the celestite 45 
 
 >rigin of the celestite 45 
 
 Serves 47 
 
 {.erenees 48 
 
 3 te 8. 
 
 Illustrations 
 Geologic map of the southeastern part of the 
 Cady Mountains, San Bernardino County, Cali- 
 fornia In pocket 
 
 9. Geologic map of celestite deposits near Ludlow, 
 
 San Bernardino County, California In pocket 
 
 ABSTRACT 
 
 he celestite deposits in sees. 29 and 30, T. 8 X., R. 7 E., S. B., 
 i he south base of the Cady Mountains about 8 miles northwest 
 )!"judlow, San Bernardino County, California, are in lacustrine 
 k ments that are the highest exposed rocks of the Tertiary system, 
 ii that are probably equivalent to the upper Miocene sediments in 
 :1 Barstow syncline. The sediments, composed of fine, thin-bedded 
 Us and clays, are overlain by gray limestones and rest upon a 
 tl'k series of volcanic flows and tuffs that range in composition 
 Er i basalt to rhyolite. The maximum exposed thickness of the 
 5t ments is about 700 feet. A part of the tuff and clay has been re- 
 p) ed by varicolored chalcedony. 
 
 he celestite is in beds and concretions in the tuff and clay, and 
 is xposed in a number of relatively small outcrops, separated by 
 al vial deposits that extend along the strike of the beds for a dis- 
 t;> e of 6,300 feet. The maximum thickness of the celestite is 112 
 I 
 
 is probable that the celestite is sedimentary in origin, but that 
 it as precipitated, after the deposition of the tuff and clay, from the 
 w ;rs contained in the sediments, and that it replaced the sedi- 
 m ts. Single celestite beds reach a thickness of only 2 feet, but zones 
 a; rick as 30 feet are estimated to be 75 percent celestite. The maxi- 
 mi thickness of 112 feet is so distributed as to constitute nearly 
 3( percent of the section. The average content of strontium sulfate 
 iude celestite rock, as determined by 14 chemical analyses, is 81 
 p< ent. 
 
 he whole deposit is inferred to contain between 1,500,000 and 
 2, 5,000 tons of celestite to a depth of 50 feet. The extent to which 
 th deposit continues in depth is unknown, but if it continues for 
 ■ feet, which is not unreasonable for a deposit of such length and 
 tl) mess, it may contain as much as 10,000,000 tons of celestite. 
 
 INTRODUCTION 
 
 he celestite deposits near Ludlow, California, were 
 ft lied in order to determine the geological relation- 
 st is of the deposits and to obtain a satisfactory esti- 
 I 3 of the reserves of celestite. This project was a part 
 oi the wartime program of investigation of strategic 
 merals by the U. S. Geological Survey. 
 
 hese deposits are located at the south base of the 
 sc heastern part of the Cady Mountains, about 8 miles 
 n< ;hwest of the town of Ludlow, San Bernardino 
 
 * blication authorized by the Director, U. S. Geological Survey. 
 Manuscript submitted for publication January 1953. 
 
 County, California (pi. 8). The celestite-bearing lake 
 beds, which dip to the south beneath the alluvial de- 
 posits of the adjacent valley, are exposed discontinuously 
 for a distance of 1J miles along the strike in sees. 29 and 
 30, T. 8 N., R. 7 E., S. B. 
 
 Very probably the celestite-bearing beds, and celestite 
 as well, are continuous beneath the alluvium that sepa- 
 rates the several outcrops. Although the several areas of 
 outcrops of celestite are referred to below as separate de- 
 posits, they are essentially parts of a single deposit. 
 
 The area of best exposures, and probably of most 
 abundant celestite, generally known as the DuPont de- 
 posit, is now owned by the Pan-Chemical Company, 
 Claremont, California. It consists of two lode claims in 
 the NEi sec. 30 (pi. 9)— the Redfire and Jasper #3— 
 that were patented in 1917 by Dana Burke. 
 
 The Rowe and Buehler deposit is located at the west 
 end of the chain of outcrops in the NW^ sec. 30 (pi. 9). 
 Wesley N. Rowe of Rosemead, California, and William 
 C. Buehler of Pasadena, California, located about 18 lode 
 and placer claims in the vicinity. Because of confusion in 
 marking the claims, it has not been possible to establish 
 on the map the boundaries of those that cover the celestite 
 deposits. 
 
 Section 29, which contains the easternmost occurrence 
 of celestite, is owned by the Southern Pacific Land Com- 
 pany. 
 
 The deposits are reached by fair ungraded roads that 
 branch from paved U. S. Highway 66 about 5| and 8 miles 
 west of Ludlow. The deposits lie about 3 miles to the north 
 of the highway. All passable roads of the district are 
 shown on the accompanying geologic map of the south- 
 eastern part of the Cady Mountains (pi. 8). 
 
 The deposits are nearly as close to the railroad as they 
 are to the highway. A spur of the Atchison, Topeka & 
 Santa Fe Railway is at Argos, and loading facilities are 
 available at Ludlow. 
 
 The region is very arid and no source of water in any 
 quantity is closer than Newberry, 30 miles to the west. 
 
 Previous Work. The only previously published work 
 on the area is that by Moore (1935, pp. 4-9 ; Hewett, et al., 
 1936, pp. 155-160). His two reports are nearly identical; 
 each contains a small-scale geologic map, two measured 
 sections, and 14 chemical analyses. The deposits are also 
 mentioned briefly in two California State reports bv 
 Tucker and Sampson (1930, p. 323; 1943, p. 543) on the 
 mineral resources of San Bernardino County. 
 
 Acknowledgments. The writer is indebted to B. N. 
 Moore, whose reports have been previously noted, for the 
 chemical analyses used in this report. The Metropolitan 
 Water District of Southern California kindly supplied 
 the topographic map which was used as a base for the 
 geologic map of the southeastern Cady Mountains. A. 
 Cowles Daley assisted the writer in the field and in the 
 preparation of the maps. 
 
 GEOLOGY 
 
 A rapid reconnaissance was made of a part of the Cady 
 Mountains in the vicinity of the celestite deposit in order 
 to obtain a general view of the geology of the district. 
 The map, plate 8, shows only the large lithologic units 
 
 (37) 
 
38 
 
 Special Report 32 
 
 and the principal structural features. Careful mapping 
 will be required to fill in the complex structural details 
 that could not be shown on a map of this scale. 
 
 The rocks of the southeastern part of the Cady Moun- 
 tains are lava flows, tuffs, and lacustrine sediments of 
 Tertiary age, except for an area of granite in the north- 
 western part of the mapped area. The ages of all the rocks 
 can only be inferred by correlation with the more com- 
 plete and better-known section in the Newberry Moun- 
 tains 30 miles to the west. The work of Gardner (1940) 
 in that region is the only general geological study of any 
 nearby area. 
 
 Stratigraphy 
 Pre-Tertiary Rocks 
 
 A light-pink, medium-grained biotite granite occurs 
 only in the northwestern part of the area mapped, but 
 extends far to the north and northeast. It is the oldest 
 rock of the area, and though its age is unknown, it is no 
 doubt pre-Cretaceous, possibly Jurassic. The granite is 
 probably equivalent to the "pink granite" in the New- 
 berry Mountains. 
 
 Tertiary Rocks 
 
 Basalt. The oldest of the Tertiary rocks, designated 
 as basalt for convenience, is a thick series consisting 
 largely of vesicular and amygdaloidal black to rust- 
 colored olivine basalt flows and flow breccias with green 
 to brown basaltic tuff, tuff -breccia, and agglomerate. Lo- 
 cally, between the strictly volcanic and pyroclastic mem- 
 bers, there are thin units of predominantly red, but in 
 places green, conglomerate, sandstone, and siltstone, com- 
 monly ripple-marked and mud-cracked, that were prob- 
 ably deposited in local basins formed as a result of vol- 
 canic activity. Much of the tuff is silicified, and the series 
 is cut by veins of calcite, manganese oxides, barite, and 
 chalcedony. 
 
 The relationship of the basalt to the older granite is 
 unknown, as the only observed contacts are faults ; but 
 probably the basalt rests on an erosion surface of the 
 granite, as in the Newberry Mountains. There rocks that 
 have been called the Rosamond series, with which the 
 writer correlates the basalt of the Cady Mountains, rest 
 directly upon the granite, according to Gardner (1940, 
 p. 280). 
 
 The thickness of the basaltic series is at least 1,000 feet, 
 and perhaps is as much as several thousand feet. 
 
 Andesite. The basalts and tuffs are overlain by a thick 
 series of reddish and gray hypersthene andesite flows 
 with local intercalations of tuff and tuff-breccia. Along 
 the south side of the range the andesite is a dense rock 
 that is mottled red and green on a fresh surface ; but 
 generally it is weathered distinctly red or purplish gray. 
 Sparse phenocrysts of plagioclase and hypersthene in an 
 aphanitic groundmass are generally aligned in the flow 
 planes. Platy jointing is well developed. 
 
 In the eastern and northwestern parts of the area, 
 where the series is thickest, the andesite is more massive. 
 Medium-sized phenocrysts of plagioclase and hypersthene 
 are abundant and are unoriented. At several places near 
 the base of the section there is light-gray to black, locally 
 vitrophyric biotite and hornblende andesite. 
 
 Veins of manganese oxide and chalcedony are abundant 
 in the andesite, and small black nodules of manganese 
 oxide are common in the joints. 
 
 The andesite rests on the basalt at the depositional co 
 tact that may possibly be an unconformity, as in t 
 Newberry Mountains to the west, where, according 
 Gardner (1940, pp. 281-283), the presumably correlate 
 Red Mountain andesite rests both on the Rosamond seri 
 and on the older granitic rocks. Proof of the unconformi 
 in the Cady Mountains was not obtainable. 
 
 The original thickness of the andesite is unknown, £ 
 the top is eroded. No section has been accurately measuri 
 because of structural complexities, but the andesite 
 about 600 feet thick near the celestite deposit, and must 
 several times that thick in the eastern part of the are 
 
 Welded Rhyolite Tuff. Along the western and sout 
 ern margins of the range the andesite is overlain unco 
 formably by a relatively thin welded rhyolite tuff. J 
 places the two types of rock are separated by a sho 
 interval of gravel and breccia composed largely of fra 
 ments of the older andesite and basalt, but with a notab 
 absence of silicified or otherwise mineralized rock. 
 
 Near the highway northwest of Lavic, and from tl 
 Rowe and Buehler celestite deposit to the Black But 
 manganese mine, the tuff overlaps the andesite and res 
 on the basalt. 
 
 The tuff is an obscurely bedded rock that contai 
 abundant crystals of quartz and of brilliantly iridesce 
 sanidine. Clastic structure is nearly always evident, b 
 where the tuff has been vitrified, the rock closely 
 sembles a flow. Spherulites have been developed in a i 
 places. Where only slightly altered, as to the east of 
 DuPont deposit, the rock is white to salmon pink, oi 
 poorly consolidated, and contains large fragments 
 pumice. Where thoroughly consolidated the tuff is gr 
 to purplish gray and is very hard and brittle. The tuff 
 about 200 feet thick. 
 
 Lacustrine Sediments. The rhyolite tuff is overla 
 conformably by a sequence of lacustrine sediments th 
 contain the celestite. At the celestite deposits the se 
 ments are greenish-yellow clay, gray tuff, and gr 
 limestone. Coarse clastic sediments are lacking. Abo 
 H miles northwest of the Rowe and Buehler deposit 
 small outcropping of the lake sediments consists of v 
 canic conglomerate and greenish tuff of rhyolitic compo 
 tion. Farther north and extending across the sumir 
 region of the range there is, preserved in the trough 
 a syncline, a sequence of coarse unconsolidated gra-\ 
 composed of fragments of the underlying andesitic roe 
 and the welded tuff. The gravel is probably equivale 
 to the lacustrine sediments at the celestite deposits, 
 overlaps the welded tuff and rests in part on the andesr 
 Probably it is a shore facies, or perhaps a fluviatile gra^ 
 of the same age as the lacustrine sediments. 
 
 The top of the lacustrine sediments is not expose 
 The thickest section, that at the celestite deposit, is abo 
 700 feet. 
 
 All the rocks here called Tertiary probably are Mioeer 
 though the lacustrine sediments might be Pliocene 
 age. Gardner (1940, p. 280) correlated the basaltic roc 
 of the Newberry Mountains with the Rosamond series 
 Rosamond Station and Mojave, and thereby implied th 
 they are Miocene, which is the accepted age of the s 
 called Rosamond series. Baker (1911, pp. 339-341) cc 
 related the beds of the Barstow syncline with the Ros 
 mond series, and the upper part of the 5,000 feet of h 
 
Strontium Deposits, Southern California 
 
 39 
 
 !i lacustrine sediments in that syncline are known to 
 ong in the upper Miocene (Merriam, 1919, p. 454). 
 
 I us probably the whole section in the Cady Mountains 
 j roughly equivalent to the section in the Barstow syn- 
 : ie, and probably the lacustrine sediments of the Cady 
 I'a are also upper Miocene. 
 
 Caternary Rocks 
 
 31der and younger alluvial deposits are present in the 
 la, but they were not differentiated on the map of the 
 my Mountains, plate 8. The older gravels cap the lower 
 • ges along the south and southeast sides of the range. 
 Ije younger deposits are the gravels and sands of the 
 p;sent stream courses and the alluvial fans of the ad- 
 vent basins. The two groups of deposits are probably 
 a. very different in age, and both are considered to 
 tyong in the Quaternary. The elevation of the older de- 
 bits is probably the result of a slight general uplift of 
 t). range, and in some places it is certainly the result of 
 r«ent faulting, as observed in the area north of the high- 
 ly near Lavic, where the gravel caps low hills of basalt, 
 
 II also in the low hills on the eastern side of the range 
 ath of Ludlow. 
 
 Structure 
 
 Ohe Tertiary rocks of the area have been folded twice 
 ll perhaps three times. Possibly the basalt was folded 
 Wore the eruption of the andesite. Folding took place 
 Bar the eruption of the andesite and before the deposi- 
 ■l of the welded rhyolite tuff, for the tuff rests both 
 )j:he andesite and basalt. This disturbance was probably 
 lompanied by faulting. The lake sediments are prob- 
 ily conformable with the welded tuff, even though 
 tl gravel in the northwest overlaps the edge of the tuff. 
 T u angle of overlap is slight, and the unconformity is 
 p bably local. After the lacustrine sediments were de- 
 puted, the strata were again folded ; this disturbance 
 w-. probably the most intense of all. It is likely that 
 rat of the faulting occurred at this time. 
 
 Jthough faulting has probably occurred at more than 
 or time it has not been possible to assign any particular 
 fejlt a definite age. The faults within the range fall into 
 ffc >e systems, the most important of which strikes north- 
 1 1. Most of the faults of this system are reverse faults 
 th dip toward the southwest, but the one shown towai'd 
 th west end of section A-A', plate 8, is a normal fault 
 th dips toward the northeast, The attitude of the fault 
 it he east end of section A-A' is not known. Two sets of 
 I s faults, one of which strikes a little east of north 
 ii the other a little north of east, are of about equal 
 m ortance. Faults of both sets terminate against those 
 I dug northwest, but they also cut off some of the 
 m or faults of that system. 
 
 he magnitudes of the fault displacements are not well 
 :i Bra, but on some of the larger faults the displacement 
 n t amount to many hundreds of feet. Possibly, how- 
 ■ , the relatively large displacements, such as are indi- 
 "a d on section A-A', plate 9, are really the sum of the 
 li lacements of many small faults that are not shown 
 oni he map but are present. 
 
 undamentally the structure of the southeastern part 
 
 f ie range is a northwest-trending anticline, which is 
 SB lgly modified by faulting. The main anticline is 
 ila ted on the southwestern side by the small syncline 
 th contains the gravels. West of this syncline there is 
 
 probably another anticline that extends from the most 
 westerly outcrops of the welded tuff to the vicinity of the 
 Black Butte manganese mine. 
 
 The range is probably separated from the adjacent 
 basins by normal faults, for this area is a part of the 
 province characterized by basin and range structure. No 
 faults of this type have been found, probably because 
 erosion has cut deeply into the range and any such 
 boundary faults are concealed beneath the resulting al- 
 luvial deposits. 
 
 The low hills north of Lavic (pi. 8) afford a clue to the 
 fault system, for basalt is here exposed at the surface, and 
 is partly capped by alluvial deposits that have been up- 
 lifted above the general level of the surrounding fans. The 
 absence of andesite may result from earlier faulting and 
 erosion, but the elevation of the hills was certainly pro- 
 duced by a more recent dislocation. The southwest-dip- 
 ping beds northwest of the Rowe and Buehler celestite de- 
 posit pass beneath alluvium toward a northeast-facing 
 scarp in the alluvium that is nearly 100 feet high. An- 
 other scarp in the alluvium that does not show clearly on 
 the map extends from a little west of Lavic station nearly 
 to the Rowe and Buehler deposit. While this scarp is prob- 
 ably no longer on the fault, it marks the approximate 
 fault line. The fault shown along the south base of the 
 range extending toward Ludlow is inferred on the basis 
 of the relationships described above. 
 
 Mineral Deposits 
 
 Veins of manganese oxides, calcite, and barite are pres- 
 ent in the region, in addition to the celestite deposits de- 
 scribed below. Manganese oxide has been mined at both 
 the Black Butte and the Lavic Mountain mine properties 
 (pi. 8). Considerable ore has been shipped from the Black 
 Butte, and the property was being worked in a small way 
 at the time of the field work (1945). The Lavic Mountain 
 manganese mine was inactive. Small veins of calcite are 
 abundant in the basalt, and several attempts have been 
 made to work them. A little calcite has been marketed for 
 chemical uses, but none of optical quality has been found. 
 Barite in thin veins is also present over the area, but only 
 the Hansen barite deposit (pi. 8) has been mined. 
 
 The manganese mineralization was younger than the 
 andesite, for veins at both mines are in that unit. The 
 absence of manganese stains, chalcedony, and silicified 
 rocks in general from the volcanic conglomerate beneath 
 the welded tuff indicates that the mineralization is 
 younger than the volcanic conglomerate. The barite min- 
 eralization cannot be easily dated, but it is probably of the 
 same general age. The calcite veins may be as old as the 
 basalt, for they are found only in that unit and the amyg- 
 dules in the basalt are dominantly of calcite. 
 
 GEOLOGY OF THE CELESTITE DEPOSITS 
 
 The geology in the immediate vicinity of the celestite 
 deposits is shown on plate 9. All outcrops of the beds as- 
 sociated with the celestite are included on the map. 
 
 There are small and isolated outcrops of the several 
 zones involved, but contact surfaces between the units are 
 rarely exposed. Therefore the contacts were extrapolated 
 in order to obtain a view of the distribution of the several 
 units, and to help in determining the positions and char- 
 acter of a number of significant but unexposed faults. 
 
40 
 
 Special Report 32 
 
 
 Stratigraphy 
 Tertiary Rocks 
 
 Basalt. Basalt enters the north-central and north- 
 western parts of the mapped area and is the oldest Terti- 
 ary rock exposed. The four small outcrops at the north- 
 west end of the area consist of fine-grained black 
 porphyritic olivine basalt with phenocrysts of plagioclase, 
 augite, and olivine. The olivine is mostly altered to 
 iddingsite. A pronounced platy jointing is present. The 
 olivine basalts of the north-central part of the area are 
 reddish brown on fresh surfaces, but they weather black. 
 In many places olivine in large phenocrysts is altered to 
 iddingsite and iron oxide. The rocks are highly vesicular 
 and amygdaloidal, and contain amygdules of calcite and 
 chlorite. 
 
 The andesite at the north quarter corner of section 30 
 (pi. 9) seems to be interbedded with the basalt. The ande- 
 site is a massive brownish-green rock with abundant un- 
 oriented small phenocrysts of plagioclase set in a dense 
 aphanitic groundmass. It is similar to the later andesite, 
 and, because it is near the top of the basaltic series, it may 
 represent an early flow of the magma type from which the 
 succeeding andesite series was derived. 
 
 Andesite. The andesite, which appears to rest con- 
 formably on the basalt, consists of an indeterminate 
 number of flows with pronounced platy jointing. Sparse, 
 small, tabular phenocrysts of plagioclase are oriented in 
 the flow planes parallel to the platy jointing. Small 
 phenocrysts of hypersthene are everywhere present, and 
 in some places there are a few of olivine. Most of the 
 groundmass is dull green, much of it streaked with pink. 
 The rock weathers purplish gray and reddish brown. 
 Zones of breccia are abundant ; they probably originated 
 both from flowage and from later tectonic disturbances. 
 The attitudes shown on the map, though measured on 
 flow banding and platy jointing, were carefully selected 
 so as to be representative of the general position of the 
 flows. The thickness of the andesite is about 600 feet. 
 
 Volcanic Conglomerate. The volcanic conglomerate, 
 so-called because its constituents are mostly volcanic and 
 pyroclastic rocks, rests unconf ormably on the andesite ; 
 it overlaps onto the basalt at the western end of the area 
 (pi. 9). The unit consists of 50 to 200 feet of coarse, 
 poorly sorted boulder conglomerate and a few thin tuf- 
 faceous pebbly sand beds. The boulders, as much as 4 feet 
 in diameter, are poorly rounded blocks of the underlying 
 andesite, olivine basalt, and associated tuff ; but, as noted 
 above, chalcedony and manganiferous and silicified rocks 
 are absent. 
 
 Welded Rhyolite Tuff. The welded rhyolite tuff rests 
 on the volcanic conglomerate and maintains a nearly uni- 
 form thickness of about 200 feet, though it may be some- 
 what thicker at the west end. Most of the welded tuff is 
 light salmon pink but weathers to purplish gray. This 
 is a well-indurated phase that breaks with a conchoidal 
 fracture. It is characterized by abundant sanidine crys- 
 tals that show a brilliant blue iridescence. A clastic struc- 
 ture can be seen with the hand lens. Near the base of the 
 two prominent hills at the west end of the area (pi. 9) 
 is a few feet of dense, black, completely vitrified tuff. 
 Some of the tuff at the east end of the deposit is poorly 
 indurated, porous, and contains pumice fragments as 
 much as 4 inches in diameter. Just east of the mapped 
 
 area a part of the tuff is entirely unindurated. Here 
 is white to cream colored and contains large pumi 
 fragments in a powdery matrix. 
 
 Lacustrine Sediments. The rhyolite tuff is overlain 1 
 the lacustrine sediments that contain the celestite. Tl 
 exposed thickness along section A- A' (pi. 9) is about 7i 
 feet, but the top is concealed by alluvium. The sequen 
 is divided on the map into several units of differing lithe 
 ogy, but it changes rapidly along the strike so that 
 generalized sequence for the several units could not 
 established. 
 
 The base of the section at the Jasper and Redfi 
 claims and to the east consists of dark yellow-green tin 
 faceous clay and tuff that contains a few thin beds 
 brown to gray limestone 2 to 4 inches thick. From 10 
 30 percent of the beds of the unit have been replac< 
 by dark-red, green, yellow, brown, and variegated cl 
 cedony. The chalcedony is in sheets an inch to 2 feet th 
 which lie parallel to the bedding of the adjacent se 
 ments. Single sheets of chalcedony can be followed 
 distances of as much as 300 feet, and then they are ter 
 nated only by the limit of exposure'. The thickness of 
 unit in the Jasper claim is about 120 feet. It contains 
 celestite there. 
 
 In section 29, east of the Jasper claim, the green cl 
 with chalcedony are very much thicker and contain, alo 
 section 1 (pi. 9), about 30 feet of celestite-bearing be 
 and still farther east, five thin beds of celestite. 
 
 Many of the beds of chalcedony are associated "w 
 iron-rich, partly silicified ocherous clays that are bri 
 red to bright yellow. Evidently ferric oxide was in 
 duced with the silica. The large pit shown at the east < 
 of the mapped area is in a body of red ocher that 
 mined there about 1927. 
 
 The green clay and chalcedony at the Jasper and R 
 fire claims are overlain by gray, cream, and light-gr 
 tuff and clay that contain the celestite. The lar 
 celestite-bearing and celestite-free zones are shown 
 plate 9. Details of the sequence are given below in s 
 tions 3, 4, and 5. Several thin zones of silicified clay a;l 
 tuff are also in this sequence. The thickness of t] 
 celestite-bearing sequence is 372 feet in section 4 and 4| 
 feet in section 5. Although sections 4 and 5 are only abet 
 1,000 feet apart, it is not possible to correlate them i 
 detail. 
 
 The celestite, tuff, and clay are overlain by limestone i 
 beds from 2 inches to 2 feet thick. The limestone unit? 
 very poorly exposed, and possibly other types of se- 
 ments are interbedded with it. The thickness of fl 
 limestone unit is not known for the top is conceal , 
 but approximately 200 feet of beds is exposed in sectii 
 A-A', plate 8. The limestone is mostly gray, fine grain . 
 and porous, but a few of the beds are pink and bu; 
 stains and nodules of manganese oxide are common. 
 
 The celestite-bearing beds thin rapidly east of l| 
 Jasper claim, and there the limestone rests directly i 
 the green clay and chalcedony. 
 
 At the Rowe and Buehler deposit, tuffs such as the 
 interbedded with the celestite at the DuPont deposit e 
 present at the base of the lacustrine sediments. Celesle 
 occurs above the tuff and is interbedded with green ai 
 purplish-red silicified clay and ocher. The limestone u t 
 is not exposed there. 
 
 
Strontium Deposits, Southern California 
 
 41 
 
 laternary Rocks 
 
 ;The older alluvium, consisting of sand and gravel, oc- 
 rjpies a terrace-like position near the north edge of the 
 ripped area, but merges into the younger alluvium along 
 h: south edge. The older alluvium rises as high as 60 feet 
 B3ve the present stream courses and is subject to erosion 
 i the higher levels. In places it is probably nearly 100 
 fi't thick. Its present position is probably due to a slight 
 i lift of the range in recent times. 
 
 The younger alluvium is the sand and gravel of the pres- 
 et stream courses. 
 
 ■Wind-blown sand is found everywhere over the area, 
 b! has been separately mapped in three places where 
 i effectively obscures the older rocks. 
 
 Structure 
 
 The Tertiary rocks strike nearly east and dip toward 
 ft south, except for minor reversals in the lake sediments. 
 • The andesite swings southward at the west end of the 
 ft'a (pi. 9) and is overlapped by the volcanic conglom- 
 e te. 
 
 The welded tuff and the lower part of the lacustrine sed- 
 iijmts dip at angles of 40° to 60°. At the east end higher 
 b'ls dip more gently, but the dip in the highest beds is 
 5j'. In general, the dips are steeper near the base of the 
 siiments; they flatten a little toward the south, and then 
 si ;i pen again as shown in section A-A', plate 8. 
 
 'n the limestone southeast of the Jasper claim, several 
 ■ill folds are present on both sides of the inferred fault ; 
 b' they are probably only local in occurrence and are 
 p sibly related in origin to movement on the fault. 
 
 Relatively few faults in the area of detailed mapping 
 w/e located by direct observation. The andesite includes 
 ir umerable zones of brecciation, but none could be traced 
 in the sediments, possibly for lack of exposure and prob- 
 m in part because they are older than the sediments. 
 TJ3 faults are shown in the andesite north of the Jasper 
 em (pi. 9). 
 
 Il small fault that offsets the base of the limestone beds 
 is<resent in the large area of outcrop about 1,500 feet 
 scjtheast of the Jasper claim. The horizontal displace- 
 Mit of the contact between the limestone and celestite 
 |B3 is not less than 160 feet. If this fault continues to 
 thj north as shown, the base of the volcanic conglomerate 
 is f set by only 30 or 40 feet. 
 
 nother fault, not actually exposed, but located fairly 
 
 ewe, is near the southwest corner of the Jasper claim. 
 
 T\i fault may be the one that is postulated to be about 
 
 If feet northeast of it. 
 
 our unexposed faults have been inferred on the basis 
 
 ■ le extrapolation of the contacts between the lacustrine 
 ^e ments, the welded tuff, and the volcanic conglomerate. 
 Tl; strike and position of the easternmost of these faults 
 
 ] 8 ) are quite closely restricted by the distribution of 
 
 ■ rops of the several units that adjoin it, and from the 
 
 that the welded tuff is present again just beyond the 
 ! of the mapped area southeast of the large pit in the 
 strine sediments. The fault probably continues toward 
 northwest, and has very likely controlled the canyon 
 
 th- cuts through the andesite at that place. The horizontal 
 
 ■ t along this fault is not known, but it must amount 
 
 'o veral hundred feet. 
 
 le inferred fault through the northeast corner of the 
 
 ha er claim is less definite in position. Its location may 
 
 be anywhere within a zone 120 feet wide, and its strike 
 may differ as much as 10° from that shown on the map. 
 The horizontal offset of the base of the limestone is about 
 450 feet. 
 
 The fault through the west end of the Jasper claim is 
 still less definitely located, though its presence is equally 
 certain. It may cross the celestite-bearing beds anywhere 
 within a zone 150 feet wide, and its strike may differ as 
 much as 15° from that shown. The horizontal displace- 
 ment of the base of the celestite-bearing zone is about 
 500 feet. 
 
 The three inferred faults described above and the one 
 exposed in the outcrops east of the Jasper claim all belong 
 to the northwest-striking system that is dominant in this 
 part of the Cacly Mountains. The fault at the west end of 
 the Kedfire claim that strikes a little east of north prob- 
 ably belongs to one of the minor systems of the range. The 
 horizontal offset of the base of the lake beds along it is 
 reckoned at 680 feet. Apparently the lake beds are dis- 
 placed somewhere between the Redfire claim and the 
 Rowe and Buehler deposit, but any number of faults with 
 various strikes could be present in the intervening 1,200 
 feet, so that the interpretation shown on the present map 
 is to be considered as only one of many possibilities. 
 Occurrence of Celestite 
 
 The greater part of the celestite is in beds, but a con- 
 siderable amount of it forms nodules or concretions in 
 clay and sandy tuff. Negligible amounts form veins or 
 bedlike bodies, in which the celestite is in transverse 
 fibers and also in loose crystals in clay. 
 
 Five sections have been measured and one estimated 
 in order to show the broad aspects of the occurrence of 
 celestite, to show the details of lithology, and to provide 
 a basis for calculation of the amount of celestite present. 
 Their positions are shown on plate 9. Sections 1 and 2 
 in the NW{ sec. 29 could not be given in detail because 
 of poor exposures. Section 3 was measured in the face of 
 the cut at the east end of the Jasper claim. This is the 
 best exposed section and is given in the greatest detail. 
 
 Section 4, a little west of section 3, is less detailed but 
 includes considerably more thickness of the beds than 3. 
 Comparison of section 3 with the corresponding part of 
 section 4 permitted the estimation with a high degree of 
 confidence of the relative amounts of celestite and sedi- 
 ments in sections 4 and 5, where the rocks are not so well 
 exposed. 
 
 Section 5, like section 4, extends the full width of the 
 celestite-bearing beds. The amount of detail given varies 
 from place to place depending on the extent of exposure 
 available. Sections 4 and 5 could not be correlated, a 
 fact that emphasizes the rapidity of change in the 
 celestite-bearing rocks along the strike. More (1935, 
 Hewett, et al. ; 1936, pp. 155-161) also measured two 
 sections, one of which is probably on the line of the 
 lower part of section 4. The other was taken between 300 
 and 400 feet west of section 4. Moore's section 1 (U. S. 
 Geological Survey Bulletin 871) is incomplete, as 50 
 feet of beds were omitted. Moore collected samples for 
 analysis along the lines of his sections, and the analyses 
 are reproduced below, but unfortunately the places 
 where the samples were collected could not be determined. 
 
 Section 6 at the west end is poorly exposed, and limited 
 by alluvial cover. There may be additional celestite both 
 above and below the exposed beds. 
 
42 
 
 Special Report 32 
 
 The quantitative aspects of the eelestite are treated 
 below in the section on reserves, but of note here is the 
 fact that in section 4, eelestite makes up 111 feet or 29.8 
 percent of 372 feet of beds; and in section 5, it makes 
 up 112.6 feet or 27.4 percent of 410.8 feet of beds. 
 
 Section 2. Northwest quarter of section 29. 
 Eighty feet of beds contain 20 feet of eelestite in beds 0.05 to 0.1 
 foot thick, and in small concretionary nodules. Intervening material 
 is powdery gypsiferous gray tuff. Celestite contains incompletely 
 replaced fragments of volcanic rock. There is probably no eelestite 
 rock at higher horizons. 
 
 Section 3. West end of cut on Jasper #3 claim. 
 
 Thickness in feet 
 Member Celestite 
 
 Top concealed. 
 
 Thin-bedded light-gray gypsiferous tuff with sev- 
 eral celestite beds 0.2 foot thick and celestite 
 nodules up to 0.2 foot thick and 0.8 foot in di- 
 ameter. Nodules contain varying amounts of 
 celestite from a cement to pure celestite. Esti- 
 mated 60 percent celestite 2.4 1.4 
 
 White powdery gypsum and green clay 0.6 
 
 Nodular bed of green celestite replacing green clay 0.2 0.2 
 
 White powdery gypsum, green clay, and fine thin- 
 bedded gray tuff 1.0 
 
 Fine-grained gray tuff 0.1 
 
 Thin-bedded gray tuff and laminated greenish-gray 
 gypsiferous and tuffaceous clay. Contains man- 
 ganiferous calcareous concretions up to 0.5 foot 
 in diameter 8.1 
 
 Laminated light-green clay and celestite in beds 
 
 0.01 to 0.03 foot thick 0.1 0.1 
 
 Laminated gray-green tuffaceous gypsiferous clay 0.7 
 
 Thin-bedded nodular celestite with streaky rem- 
 nants of red and green clay 0.2 0.2 
 
 Laminated dark-green tuffaceous clay 0.5 
 
 Nodular green celestite beds separated by films and 
 thin layers of green clay. Gypsum in veinlets. 
 Estimated 60 percent celestite 2.0 1.2 
 
 Massive white celestite with central zone of gray 
 
 chalcedony replacing celestite 1.9 1.9 
 
 Laminated greenish-gray tuffaceous clay and celes- 
 tite 0.2 
 
 Nodular to smooth-surfaced white celestite in beds 
 from 0.1 to 0.8 foot thick separated by partings 
 of greenish-gray tuffaceous clay. Estimated 90 
 percent celestite 2.8 2.5 
 
 Greenish-gray tuffaceous clay, with three celestite 
 layers replacing sandy gray tuff, each ranging 
 from 0.01 to 0.1 foot in thickness 1.6 0.2 
 
 Nodular celestite beds up to 0.7 foot thick sepa- 
 rated by films to beds 0.3 foot thick of gray tuf- 
 faceous clay. Estimated 80 percent celestite 8.0 6.4 
 
 Very thin-bedded white and green celestite with 
 partings of green clay. Contains red-brown and 
 green chalcedony 0.1 foot thick. Estimated 90 
 percent celestite 2.0 1.8 
 
 Green gypsiferous clay grading into red chalcedony 
 
 and ocher 
 
 Total 32.4 15.9 
 
 Percent celestite 49.1 
 
 Section //. East end of Jasper #3 claim. 
 
 Top of section concealed 
 
 Poor exposure of white celestite. Intervening sed- 
 iments not exposed. Could not estimate propor- 
 tion of celestite 12 
 
 Concealed. May contain some celestite 38 
 
 Red-brown chalcedony and brown limestone beds, 
 partly oolitic, as much as 0.5 foot thick 14 
 
 Section Jf. East end of Jasper #3 claim— continued. 
 
 Thickness in fe 
 Member Celest 
 
 Dark-green clay shale and dark-green chalcedony 4.5 
 
 White celestite in beds as much as 0.3 foot thick. 
 
 Estimated 75 percent celestite 11.1 8.3 
 
 Poorly exposed. Contains at least 3 feet of celestite 7.3 3.0 
 
 Unexposed. Probably contains some celestite 13.5 
 
 Pink and white celestite in beds as much as 0.4 foot 
 thick separated by partings of clay. Estimated 
 95 percent celestite 4.6 4.4 
 
 [Offset in line of section] 
 
 Thin-bedded gray and pinkish-gray tuff with some 
 
 green clay 28.6 
 
 Nodular beds of white celestite 0.5 foot thick sep- 
 arated by partings of gray tuff and gray clay. 
 Estimated 95 percent of celestite 12.8 12.5 
 
 Laminated yellow-green clay partly silicified. In- 
 cludes thin beds of chalcedony and chalcedonic 
 limestone 3.8 
 
 Reddish-gray chalcedonic limestone 0.3 
 
 Thin-bedded white, pink, and green celestite in beds 
 as much as 0.15 foot thick separated by green 
 clay and gray tuff. Estimated 85 percent celestite 6.5 5.5 
 
 Green clay with abundant nodules of celestite with 
 a maximum diameter of 0.3 foot. Some gray tuff. 
 Estimated 30 percent celestite 5.5 1.8 
 
 Gray and white celestite in beds from 0.05 to 0.7 
 feet thick with partings and beds of gray tuff 
 and green clay as much as 1.0 foot thick. Celes- 
 tite contains some chalcedony and manganese 
 stains. Estimated 75 percent celestite 13.3 10.0 
 
 Gray tuff and green clay with a few beds of celes- 
 tite up to 0.1 foot thick 8.0 
 
 White and pale-pink celestite in beds from 0.05 to 
 0.5 foot thick separated by partings of gray tuff. 
 Estimated 85 percent celestite 7.1 6.1 
 
 Gray sandy tuff with a few beds of celestite ; the 
 
 largest are 0.2 foot thick 16.4 
 
 White celestite in beds as much as 0.6 foot thick, 
 mostly about 0.2 foot thick, separated by gray 
 tuff and gray-green clay. Estimated 75 percent 
 celestite 11.7 8.£ 
 
 Gray tuff 0.4 
 
 White celestite 0.2 0.- 
 
 Gray tuff 1.2 
 
 Reddish celestite 0.4 0.4 
 
 [Top of section 2] 
 
 Thin-bedded gray tuff and gray-green laminated 
 clay with a small amount of celestite near the 
 top 14.6 
 
 Celestite in beds as much as 0.3 foot thick sep- 
 arated by green clay and gray tuff. Estimated 
 50 percent celestite 4.8 2.- 
 
 Massive white celestite with black chalcedony at 
 the center of the bed. Estimated 75 percent celes- 
 tite 2.0 1.! 
 
 White celestite in beds 0.01 to 0.5 foot thick, mostly 
 about 0.1 foot thick, separated by gray tuff and 
 green clay. Estimated 75 percent celestite 22.2 16.' 
 
 [Base of section 2] 
 
 Red ferruginous clay and red chalcedony (shown 
 
 on map) 2.6 
 
 Gray tuff, poorly exposed 4.9 
 
 Celestite in beds ; the largest are 0.15 foot thick 
 alternating with gray tuff and green clay. Esti- 
 mated 50 percent celestite 3.1 lJ 
 
 Red chalcedony 0.5 
 
 Dark yellow-green clay with abundant nodules of 
 green and red chalcedony and thin beds of green 
 celestite. Estimated 25 percent celestite 5.9 1. 
 
Strontium Deposits, Southern California 
 
 43 
 
 Section If. Eaxt end of Jasper #3 claim — continued. 
 
 Thickness in feet 
 
 J Member Celestite 
 
 rk yellow-green clay with beds of white celestite 
 
 is much as 0.3 foot thick and totaling 0.6 foot— 1.2 0.6 
 
 I rk red-brown clay and tuffaceous sand with beds 
 
 if ferruginous red chalcedony as much as 0.1 foot 
 
 hick 1.9 
 
 Mules and nodular beds of green celestite and 
 
 reen and red chalcedony in sparse matrix of 
 
 !ark yellow-green clay. Estimated 30 percent 
 
 elestite 8.7 2.6 
 
 (estite in beds from 0.01 to 1.0 foot thick sep- 
 
 rated by thin partings of green clay. Estimated 
 
 8 percent celestite 5.4 5.3 
 
 Oen clay with very little celestite 3.2 
 
 Vite celestite in beds, the largest 0.2 foot thick. 
 
 Estimated 75 percent celestite 6.3 4.7 
 
 (;en clay with a little celestite in beds about 0.1 
 
 oot thick, and one 0.1 foot layer of fibrous cel- 
 
 stite 34.2 
 
 Oenish-white and green celestite in thin beds. 
 
 Estimated 98 percent celestite 1.4 1.4 
 
 F>rly exposed. Gray and green celestite float and 
 
 eds of dark green celestite as much as 0.1 foot 
 
 Slick. Much silicified clay and celestite. Esti- 
 
 lated 25 percent celestite 14.5 3.6 
 
 Ik yellow-green celestite with partings of green 
 
 lay. Estimated 98 percent celestite 1.7 1.7 
 
 In-bedded green celestite with partings of green 
 
 ay 0.8 0.8 
 
 I k yellow-green, gray, and white celestite, partly 
 
 licified, in beds as much as 0.1 foot thick. Fi- 
 
 rous celestite near the base 3.0 3.0 
 
 In-bedded green and gray celestite, green clay, 
 
 ad gray tuff. Estimated 30 percent celestite___ 7.9 2.6 
 
 [ se of celestite-bearing zone] 
 
 Total 372.0 111.0 
 
 Percent celestite 29.8 
 
 Section 5 Redfire claim. 
 
 concealed 
 hin-bedded nodular gray limestone with part- 
 
 gs of green shale 12.0 
 
 k red and yellow chalcedony, probably silici- 
 
 :d tuffaceous clay 2.6 
 
 ow-green tuffaceous clay with pink siliceous 
 id maganiferous limestone beds, the largest 0.2 
 ot thick 13.7 
 
 9 of celestite-bearing beds] 
 
 l-bedded gray tuff with beds of celestite from 
 
 1 to 0.3 foot thick. Estimated 75 percent celes- 
 
 :e 1.8 
 
 i-bedded to massive white celestite 11.7 
 
 )w-green tuffaceous clay and green, pink and 
 own celestite in nodules and in beds as 
 uch as 1.1 feet thick. Estimated 50 percent 
 lestite 44 
 
 t gray tuff nodules and thin beds of celestite 
 
 d very small nodules of manganese oxide 4.2 
 
 te celestite in beds as much as 1.0 foot thick 
 ntaining streaks and small nodules of manga- 
 se oxide, separated by partings of gray tuff 
 d gray-green tuffaceous clay. Estimated 95 
 
 rcent celestite 10.4 
 
 t gray tuff and gray-green clay. Very poorly 
 
 posed. Contains a little celestite 23.7 
 
 te celestite in beds, the largest 1.0 foot thick. 
 
 orly exposed. Estimated 75 percent celestite 29.1 
 
 Thickness in feet 
 Member Celestite 
 
 Not 
 
 included 
 
 in 
 
 total 
 
 1.3 
 
 11.7 
 
 2.2 
 
 9.9 
 
 21.8 
 
 Section 5. Redfire claim — continued. 
 
 Thickness in feet 
 Member Celestite 
 
 Thin-bedded gray tuff and gray-green clay con- 
 taining very little celestite 9.8 
 
 Light pink and white celestite in beds as much as 
 0.6 foot thick interbedded with gray gypsifer- 
 ous tuff and powdery white gypsum. Estimated 
 60 percent celestite 9.3 5.0 
 
 Gray gypsiferous tuff and white powdery gypsum 
 that contain nodules of celestite mostly less 
 than 0.1 foot in diameter 4.3 
 
 White celestite in beds as much as 0.2 foot 
 thick. Poorly exposed. Estimated 75 percent 
 celestite 13.4 10.3 
 
 Dark green clay and nodules of green and red chal- 
 cedony and green celestite 1.7 
 
 Gray tuff, gray-green gypsiferous clay, and powdery 
 
 white gypsum 33.0 
 
 White celestite in beds as much as 0.3 foot thick. 
 
 Estimated 85 percent celestite 8.3 7.0 
 
 Unexposed. Probably gray tuff without celestite 11.1 
 
 White celestite in beds, the largest 0.6 foot thick. 
 
 Estimated 90 percent celestite 7.0 6.3 
 
 Gray tuff 10.8 
 
 Dark green shale, partly silicified 1.4 
 
 White celestite in beds as much as 0.8 foot thick 
 and partings of gray-green clay. Estimated 98 
 percent celestite 4.2 4.1 
 
 Thin-bedded gray tuff and gray-green shale. Poorly 
 
 exposed 18.2 
 
 Poorly exposed. Probably mostly dark green tuf- 
 faceous clay 25.5 
 
 Red chalcedony 3.5 
 
 Dark to light green tuffaceous clay 4.0 
 
 Poorly exposed. Mostly dark green partly silicified 
 tuffaceous clay and beds of celestite about 0.1 
 foot thick at intervals of 1 to 2 feet. Nodules of 
 w T hite celestite, as much as 0.2 foot in diameter 
 and mostly coated with chaledony, occur at 
 several places. Amount of celestite is negligible 40.0 
 
 Light gray and pink tuff and beds of white celes- 
 tite ; the largest are 0.2 foot thick. Estimated 10 
 percent celestite 15.6 1.6 
 
 Thin-bedded white celestite. Estimated 75 percent 
 
 celestite 2.5 1.9 
 
 Poorly exposed. Gray tuff and some celestite 16.5 
 
 White celestite in beds as much as 0.2 foot thick. 
 
 Partly silicified. Estimated 75 percent celestite 9.0 6.7 
 
 Light gray tuff containing a little celestite 24.0 
 
 Thin-bedded white and gray siliceous celestite. 
 
 Estimated 50 percent celestite 9.5 4.7 
 
 Poorly exposed. White celestite in beds as much as 
 
 0.4 foot thick. Estimated 75 percent celestite 10.5 7.9 
 
 Partly silicified clay shale and orange chalcedony, 
 and thin beds of celestite. Estimated 20 percent 
 celestite 9.5 1.9 
 
 White celestite in beds as much as 0.4 foot thick. 
 
 Estimated 75 percent celestite 5.0 3.7 
 
 Dark green party silicified shale and some celes- 
 tite 5.2 
 
 White celestite in beds, the largest 0.3 foot thick. 
 
 Estimated 80 percent celestite 3.2 2.6 
 
 Gray tuff and gray-green clay 3.5 
 
 Thin-bedded light green celestite, green clay, and 
 
 gray tuff. Estimated 50 percent celestite 4.0 2.0 
 
 Dark green clay shale and dark green chalcedony 2.0 
 
 (Base of celestite-bearing zone) 
 
 Total 410.8 112.6 
 
 Percent celestite 27.4 
 
44 
 
 Special Report 32 
 
 Section G. Bone and Buckler deposit. 
 
 Thickness in feet 
 Member Celestite 
 Top concealed 
 
 Dark blackish-green and purplish-red gypsiferous 
 
 shale 2.9 
 
 Platy gray tuff, partly silicified 0.7 
 
 Dark blackish-green and purplish-red gypsiferous 
 
 clay 2.3 
 
 Thin, platy porcellaneous celestite and partings 
 
 of dark green clay. Estimated 98 percent celestite 0.8 0.8 
 
 Blackish-green clay 3.3 
 
 Dark green and dark red ocherous clay and beds of 
 
 dark green and red chalcedony 35.1 
 
 Light to dark green tuffaceous clay and pale green 
 
 to white tuff 3.4 
 
 Light green tuffaceous clay and a few thin beds of 
 
 light green celestite 1.4 
 
 Thin-bedded nodular pale green to white celestite 2.7 2.7 
 
 Light green tuffaceous shale and tuff with nodules 
 
 and thin beds of celestite. Estimated 40 percent 
 
 celestite 2.2 0.9 
 
 Dark to light green tuffaceous clay 6.6 
 
 Platy green chalcedony 0.3 
 
 Lower beds poorly exposed, but probably do not 
 
 contain celestite 
 
 Total 61.7 4.4 
 
 Percent celestite 7.1 
 
 The bedded celestite has various aspects depending on 
 color, which is largely controlled by impurities, and on 
 the grain form and size. Most of it is light gray to white, 
 and much is light green. The latter color is evidently due 
 to small amounts of green clay between the grains of celes- 
 tite. Lesser amounts are light to dark brown, dark gray, 
 and pink. The maximum grain size of the celestite is 
 about 1 mm, but only a very little is that coarse. Most of 
 it is obviously granular, with equidimensional grains, but 
 some is so fine grained as to be porcelaneous. A little of 
 the celestite at the east end of the area consists of acicular 
 crystals, so disposed that their length is parallel to the 
 bedding planes. 
 
 The commonest impurity is light- to dark-green clay. 
 Gray and pink chalcedony has replaced a part of the celes- 
 tite in some beds, and Moore (Hewett, et al., 1936, p. 156) 
 reports it to be in small amounts in all of the celestite. 
 Stains of manganese oxide are common, and small nodules 
 of manganese oxide 1 to 3 mm in diameter are abundant 
 in some beds, and are also found attached to the surfaces 
 of beds. 
 
 Most of the celestite is interbedded with sandy gray 
 tuff and light- to dark-greenish-yellow clay. The beds of 
 celestite range in thickness from mere films to 2 feet. 
 Units 10 to 12 feet thick are composed almost entirely of 
 celestite, but they are bedded and weather into homo- 
 geneous slabs mostly between 0.1 and 0.5 foot thick. The 
 bedding planes in less-pure celestite are marked by layers 
 of impure material or by films and thin beds of clay or 
 tuff. Some of the less-pure celestite is shaly; it splits 
 readily into laminae 1 to 2 mm thick. Most of the celestite 
 is granular and some consists of aggregates of needles. 
 Celestite cements some of the sandy tuffs. 
 
 The beds of celestite seemingly have sharp contacts 
 with the adjacent sediments, but in detail, particularly 
 where celestite beds are in tuff, there is a transition zone 
 
 1 to 10 mm thick. The surfaces of the beds are usually 
 gently wavy to strongly nodular. Beds thin and thicker 
 rapidly and terminate either by tapering out or by a grad- 
 ual transition from celestite to sediment. In the first typt 
 of termination the decrease in thickness of celestite i< 
 compensated by a thickening of the sedimentary material 
 Concretions of celestite are sometimes present at the sam( 
 horizon beyond the ends of beds. 
 
 Concretions of celestite in sandy tuff are exposed in th< 
 highest bed described in section 3, in the face and soutl 
 wall of the large cut at the east end of the Jasper #3 claim 
 Concretions 0.2 foot thick and as much as 0.8 foot in di 
 ameter are present in a tuff bed 0.2 foot thick. They ari 
 quite pure at the center, but impurities increase towart 
 the margin so that they grade completely and gradually 
 into tuff. Tuff, weakly cemented with celestite, extend 
 beyond the surface of the hard firm body of the concre 
 tions. Concretions are separated in the bed by a few inche 
 to a few feet of tuff. The thickness of the concretions i 
 controlled and limited by the thickness of the bed in whicl 
 they lie. 
 
 The concretions in the clay are somewhat different frou 
 those in the tuff for they are more sharply defined at th 
 margins and consist of dense fine-grained white or grep) 
 celestite. They are more irregular in form and resembl 
 knobby potatoes in both size and shape. Their maxinvur 
 diameter is about 0.3 foot. In some places they are parti; 
 to wholly replaced by chalcedony, and a few are coate* 
 with chalcedony. Some of the nodules have a "brea< 
 crust" surface on one side, formed of polygonal craefo 
 
 The nodules are widely scattered in some beds, but i 
 many beds they constitute 30 to 50 percent of the mass 
 In a few places they are so closely spaced that only film 
 of clay remain between them. The general appearance c 
 nodules when crowded together suggests that some of th 
 highly nodular beds were formed by the coalescence c 
 nodules localized in a particular zone. 
 
 Two layers of fibrous pale blue translucent celestii 
 occur near the base of section 4, and a layer is preser. 
 near the top of the lowest celestite-bearing unit shown o 
 the map a little west of section 5. All three layers consi; 
 of fibers or columns of celestite with their length norm; 
 to the margins of the layers, which range in thickne; 
 from 0.05 to 0.2 foot. Though uncertain because of poc 
 exposure, one of the layers near the base of section 
 seems to strike at an angle of about 15° from the strike i 
 the beds. The other two layers are parallel to the beddin 
 The structure of the layers is like that so commonly fovu 
 in gypsum, which suggests that the celestite may ha 
 replaced and pseudomorphed gypsum. 
 
 Separate celestite crystals and rosettes of crystals occi 
 in green clay in the ravine about 90 feet northeast of i 
 strument station T in the NWj sec. 29. The lowest be< 
 exposed here are dark green poorly consolidated Ian 
 nated clay-rich celestite rocks consisting of short prisr 
 and needles of celestite 1 to 3 mm long, which are a 
 ranged with their length parallel to the bedding plane 
 About 5 feet of this rock is overlain by about 10 feet < 
 dark green clay without celestite ; and this clay, in tur 
 is overlain by alternate beds, about a foot thick, of barn 
 clay, and of clay that contains separate celestite crysta 
 The crystals are rough prisms, some of which have poor 
 developed terminal faces. They are mostly 5 to 10 m 
 
Strontium Deposits, Southern California 
 
 Table 1. Analyses of celestite rock. 
 
 45 
 
 (Number 
 
 SiOj 
 
 AhOs 
 
 Fe 2 Oa 
 
 CaO 
 
 MgO 
 
 SO s 
 
 C0 2 
 
 H 2 
 
 SrO 
 
 BaO 
 
 MnO 
 
 SrSO* 
 calculated 
 from SrO 
 
 1 
 
 2.05 
 2.80 
 7.05 
 
 0.45 
 . 55 
 1.80 
 
 0.15 
 
 1.55 
 0.75 
 1.65 
 
 
 40.80 
 41.20 
 37.30 
 34.34 
 38.33 
 34.49 
 35.85 
 41.41 
 29.88 
 31.52 
 36.89 
 31.49 
 36.88 
 41.08 
 
 Little 
 
 Little 
 
 Little 
 
 None 
 
 Trace 
 
 0.03 
 
 None 
 
 0.70 
 
 Trace 
 
 7.90 
 
 1.40 
 
 0.27 
 
 4.05 
 
 0.30 
 
 0.50 
 0.55 
 
 1.10 
 
 50.50 
 51.55 
 47.75 
 43.35 
 48.53 
 44.35 
 44.39 
 50.53 
 36.16 
 39.52 
 45.29 
 40.55 
 47.73 
 52.35 
 
 0.13 
 0.63 
 0.26 
 0.64 
 0.73 
 0.09 
 
 None 
 
 0.005 
 
 0.02 
 
 Trace 
 
 Trace 
 
 None 
 
 None 
 
 None 
 
 Trace 
 
 0.17 
 
 0.05 
 
 Trace 
 
 0.02 
 
 Trace 
 
 89.5 
 
 
 
 91.4 
 
 3 
 
 4 
 5 
 6 
 7 
 8 
 9 
 10 
 
 11 
 
 12 
 13 
 
 14 
 
 rage SrSO 1 
 
 
 
 84.6 
 
 
 
 76.8 
 
 
 
 
 
 
 
 86.0 
 
 18.02 
 
 0.66 
 
 0.05 
 
 0.96 
 
 
 
 78.5 
 
 
 
 78.6 
 
 
 
 
 
 
 
 
 89.6 
 
 
 
 
 
 
 
 1.70 
 0.76 
 0.51 
 1.19 
 1.14 
 1.07 
 
 64. 1 
 
 
 
 
 
 
 
 70.0 
 
 
 
 
 
 
 
 80.3 
 
 17.86 
 2.20 
 1.53 
 
 0.98 
 0.21 
 0.92 
 
 0.38 
 0.46 
 0.54 
 
 2.81 
 5 . 34 
 0.97 
 
 0.17 
 0.08 
 0.11 
 
 1.60 
 0.03 
 0.56 
 
 72.0 
 84.6 
 92.6 
 
 81.3 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ysts: 1 to 3, It. K. Bailey; 4, 5, 9, 10, 11, R. C. Wells: 12 to 14, C. Milton: 6 to 8, R. E. Stevens. 
 
 pses 1 to 5 are Moore's samples 1, 3, 4, 5, and 6, from his section 1, analyses 6 to 14 are his samples 1 to 9 from his section 2. 
 
 <g, but a few are 15 mm long and 3 mm in diameter. 
 K orientation of the crystals within the bedding planes 
 Ui discernible. One bed contains spherical rosettes of 
 P , gh prisms from 20 to 50 mm in diameter. The largest 
 dthe component crystals are about 25 mm long and 3 to 
 4 1m thick. 
 
 Chemical Composition of the Celestite 
 
 fourteen analyses of samples collected by Moore (Hew- 
 etet al., 1936, p. 161) are presented in table 1. All of the 
 anples were taken along the lines of Moore's sections 1 
 ai 2. The present writer has not been able to establish 
 tl: exact locations of the samples in the field, but they are 
 I ely spread and are no doubt representative of the 
 dtosit. 
 
 'he range of SrS0 4 in the 14 samples is from 64.1 to 
 9£ i percent, and the average is 81.3 percent. The analyses 
 ai Moore's sections indicate that all the samples were 
 material appropriately called "celestite rock" accord- 
 in to the present writer's use of that term. The samples 
 injuded celestite of several colors and, according to the 
 I 'riptions, of various amounts and kinds of impurities 
 efc:pt that probably none contained large amounts of clay. 
 Miurities in the celestite rock, notably silica, seem to be 
 I abundant than in the analyzed samples. The celestite 
 w on the whole is probably of a little higher grade than 
 is dicated by Moore 's analyses. 
 
 he principal impurities revealed by the analyses are 
 siljja and lime. The most siliceous celestite probably could 
 ie asily avoided in mining. The maximum lime content 
 ai 34 percent, but the average is only 2.0 percent. All 
 )fcr impurities are small in amount except barium oxide, 
 whh is present in an amount greater than 1 percent in 
 eli of four samples. 
 
 Origin of the Celestite 
 
 [isposition in beds and concretions suggests at once 
 thi the celestite is sedimentary in origin. Nothing about 
 tkbecurrence suggests any other mode of origin. Moore 
 ■!5, pp. 3, 20) concluded that the celestite was sedi- 
 wjtary and apparently was directly precipitated from 
 h- ake waters, an origin that he assigned to all the celes- 
 
 tite deposits of southeastern California and western Ari- 
 zona that he examined. The writer agrees that the Ludlow 
 deposits are probably sedimentary, but indirectly so, for 
 abundant field evidence shows that the celestite has re- 
 placed preexisting sediments. 
 
 Beds of celestite, like gypsum or other salines, can read- 
 ily be conceived to have been precipitated from water, 
 and to have settled to the lake floor. In this way bedded 
 deposits of varying degrees of purity could be formed, 
 depending on the relative rates of precipitation of the 
 saline mineral and deposition of epiclastic or pyroclastic 
 material. Also the nodular masses might form by direct 
 precipitation if the inflow of clastic material was very 
 slow. Nodules formed in this way would be expected to 
 be on bedding surfaces, and the younger beds would be 
 expected to curve over them. The nodules might also be ex- 
 pected to show some concentric structure resulting from 
 accretion, either bands due to variations in rate of growth 
 or a concentric disposition of included impurities such 
 as grains of sand. Conceivably the separate needles of 
 celestite in the clay could have formed by direct precipi- 
 tation, but it is not easy to see how the rosettes could have 
 formed in that manner. 
 
 Many other features of the celestite militate against the 
 concept of direct precipitation. Celestite beds terminate 
 by lateral gradation into well bedded sandy tuff, and taper 
 into such tuff or clay. The transitions take place within 
 a few feet, and the decreased thickness of celestite is 
 balanced by an increased thickness of sediments. It is 
 hardly conceivable that such a variation could have formed 
 by direct precipitation, for it would require that clastic 
 and chemical sediments were deposited to the same thick- 
 ness in the same interval of time, each in a relatively pure 
 state at places only a few feet apart laterally. Such a rela- 
 tionship can arise only through the replacement of sedi- 
 ment by celestite. This view is supported by the fact that 
 the most pure and massive celestite shows bedding on 
 weathered surfaces ; and where celestite beds terminate, 
 the bedding planes continue into the adjacent sediments. 
 
 The concretions of celestite in sandy tuff are mostly 
 small bodies whose thickness is controlled by the thickness 
 of the enclosing bed. Not only the lower surface but the 
 uj)per surface as well is controlled by bedding planes in 
 
46 
 
 Special Report 32 
 
 the tuff, and bedding features within the larger unit pass 
 into the concretions. The concretions grade into sediments 
 at their margins, and tuff that is loosely cemented with 
 celestite is present beyond their margins. Such bodies can 
 form only by replacement. Whether the tuff was dissolved 
 and carried away or the grains were displaced mechani- 
 cally, or whether both processes took place as the celestite 
 was deposited is not known, but certainly celestite was 
 deposited in, and took the place occupied by, preexisting 
 sedimentary material. 
 
 The nodules of celestite in clay have the same origin, 
 although they are slightly different in appearance. In a 
 general way they are regular in outline, but have some- 
 what knobby surfaces. Internally they are composed of 
 pure, dense homogeneous white or greenish celestite. They 
 are in places closely crowded with only a little clay be- 
 tween them. They lie at all levels in the clay and are not 
 obviously controlled by bedding. They have a form and 
 habit that is typical of concretions. They could only have 
 formed by replacement, which is also the commonly rec- 
 ognized mode of origin of concretions of calcium carbonate 
 in shales. 
 
 Celestite nodules in clay and concretions of celestite in 
 tuff are closely associated with beds of celestite, many of 
 which have nodular surfaces. The obvious conclusion is 
 that beds were formed by the coalescence of concretions, 
 which were limited in thickness by lithologic variations 
 in the original sediment. Trains of concretions at a com- 
 mon horizon beyond the termination of a bed also indicate 
 that mode of origin for the beds. This relationship was 
 also observed by Moore (1935, p. 8). 
 
 A few fragments of a volcanic rock, possibly the an- 
 desite that underlies the celestite-bearing beds, were found 
 in celestite in the trench along section 1. Although the 
 fragments were not examined microscopically, they are 
 apparently partly replaced by celestite at their margins. 
 
 The acicular crystals of celestite in clay, described 
 above, seem at first to be strong evidence in favor of direct 
 precipitation. However, the associated rosettes of crystals 
 could not have been formed by direct precipitation, for 
 they are spherical. As the crystals of the rosettes point 
 outward in all directions, downward as well as upward, 
 they could only have formed within the clay, and not upon 
 a surface of clay. The separate needles could also have 
 formed in the clay. 
 
 The fibrous celestite, which was found at three locali- 
 ties, is puzzling. Two of the layers are parallel to the bed- 
 ding of the enclosing rocks but the third may be transgres- 
 sive. The material may have formed by solution and 
 redeposition of celestite in an opening, or it may have 
 formed by the replacement of gypsum. In any event, it 
 does not affect the belief that the other celestite was of 
 replacement origin. 
 
 The writer concludes that the celestite, with the possible 
 exception of the three fibrous layers, has formed by the 
 replacement of preexisting sedimentary material. 
 
 The deposit furnishes no direct evidence of the time 
 of replacement, but it probably took place immediately 
 after deposition of the sediments before they were lithi- 
 fied and dried out. The agency of replacement would then 
 be the connate waters that saturated the sediments. Noth- 
 ing contrary to this view has been seen. No direct evidence 
 
 indicates that the sediments had been disturbed by faull 
 ing or folding before replacement. 
 
 If this view is correct the possible origins of the stror 
 tium are several : (1) it may have been in the lake water: 
 perhaps concentrated in them by evaporation before it wa 
 trapped in the sediments as connate water; (2) it ma 
 have been precipitated from the lake waters and disperse 
 through the clastic sediments and later dissolved and loca 
 ized by replacement; (3) it may have been in the tuff i 
 an original dispersed constituent and later localized b 
 solution and redeposition; (4) it may have been intri 
 duced directly into the sediments in solutions rising froj 
 a deeper, perhaps igneous source. A choice can not t 
 made among the several possibilities, but they merit son 
 further discussion. 
 
 The first possibility seems to be a competent immedia' 
 source, though it may be argued that unless the wate: 
 circulated and the strontium was replenished, such a larf 
 body of celestite could not have been formed. Probab! 
 neither the circulation nor the replenishment is demo: 
 strable and in any event the important question of tl 
 original source of the strontium is left open. The stro: 
 tium could have been derived in the first two possible o 
 igins by general weathering of the rocks of the draina< 
 basin. These are largely volcanic and pyroclastic rock 
 and they could possibly have constituted a source, thou^ 
 nothing is known of their strontium content. The str 
 tium could also have been derived from solfataras 
 spring waters, partly of juvenile origin, which broug 
 strontium solutions from a deep source directly into 
 lake, or to the surface of the surrounding drainage bas 
 
 The third possibility is a variant of the second : it p 
 tulates the introduction of the strontium directly in 
 the sediments of the lake without involving the intern 
 diate step of solution in the lake waters. As in the secoi 
 possible origin, no data are available as to the strontii 
 content of the tuff or of any of the volcanic materials 
 the region. 
 
 The last possibility, namely that the strontium was 
 troduced directly into the sediments by rising hydi 
 thermal solutions, can be supported in part by a somewl 
 devious argument. Some of the lake sediments, below t 
 celestite, have been intensely silicified and this silicifii 
 tion was accompanied by the introduction of ferric oxii* 
 Probably the silica and iron were both of hydrotheri 
 origin, as veins of identical material are abundant alsoi 
 the older rocks of the Cady Mountains. Identical materia 
 are interbedded in the celestite, and the celestite is par' 
 silicified. The silica and iron were thus hydrotherma? 
 introduced later than the celestite, but probably not mil 
 later. Veins of chalcedony, manganese, and barite 
 present in the older rocks that also have been extensivj 
 silicified. The manganese mineralization is certainly p(' 
 andesite, and very probably all the hydrothermal minei- 
 ization is post-volcanic conglomerate, for mineralized r 
 silicified fragments were not found in the volcanic el 
 glomerate. Therefore the mineralization in the hig.J 
 parts of the Cady Mountains may be the same age as .9 
 hydrothermal alteration of the lacustrine sediments. r i 
 age of mineralization is also supported by the occurre e 
 of small nodules of manganese within and on surfaced 
 the celestite, which are therefore younger than the ces- 
 
 
Strontium Deposits, Southern California 
 
 47 
 
 te, and by the presence of barium oxide in the celestite, 
 a shown in the analyses. Conceivably the strontium was 
 i roduced in an early phase of this episode of hydro- 
 t'rmal activity. 
 
 Df course no assumption can be made as to whether the 
 sontium went directly into the connate waters of the 
 s iiment, or whether it went first into the lake waters and 
 In was incorporated into the sediment by means of one 
 ) the first two processes discussed above. 
 
 The idea that the source of the strontium was in hydro- 
 i rmal solutions derived in connection with igneous ac- 
 fcity has one merit above the others. It suggests a corn- 
 pent means of concentration of a substance that is so 
 ulely dispersed in the surface rocks that its localization 
 iisuch abundance by epigene processes is scarcely cred- 
 it. 
 
 RESERVES 
 
 ?he amount of celestite rock available to any assumed 
 rbth can be estimated from the data of the measured 
 scions. These data are summarized in table 2. 
 
 Sections 4 and 5 include the full thickness of the celes- 
 ti -bearing beds. Section 3, close to section 4, does not, and 
 isherefore not used in the calculations. 
 
 lection 6 is only a partial section as the top is not 
 e:osed. Possibly there is more celestite rock in both 
 ther and lower beds in that area, but no basis was 
 fend for estimating the amount. 
 
 'he depth to which the celestite rock may continue is 
 oi:nown. An inclined shaft near the center of the Jasper 
 el'm follows the bedding to a depth of 30 feet, and the 
 ee stite rock is the same at the bottom as at the top. The 
 aestite rock is exposed through a maximum vertical 
 Kge of 75 feet in the Redfire claim. The final depth 
 atvhich celestite may be present depends, of course, on 
 tb original extent of the deposit and the degree to which 
 ch deposit has been eroded. If the present level of erosion 
 is ear the upper edge of the deposit, tbe celestite rock 
 mi; extend for several thousand feet, but as now known 
 it ould terminate only a few feet below the present 
 expsed level. In view of the great length of the deposit, 
 wish is 6,300 feet, little doubt remains that celestite rock 
 3x nds at least to an average depth of 50 feet below the 
 ■'ace. 
 
 elestite is well exposed over a length of 1,800 feet in 
 h. Jasper and Redfire claims. It has an aggregate thick- 
 ite of slightly over 110 feet in sections 3 and 4, and 
 tfce is no reason to believe that any lesser value should 
 *ty to the full length. The thickness of celestite rock 
 le eases sharply east of the Jasper claim, although some 
 on undoubtedly is present there. At the west end of the 
 leisit, 2,900 feet beyond the western limit of outcrop 
 onf,he Redfire claim, only 4.4 feet of celestite rock is 
 exrsed in section 6, although possibly other beds are 
 ;)rent at higher stratigraphic positions. 
 
 le specific gravity of the celestite rock is assumed 
 tits 3.64, which allows for 19 percent of impurities of 
 ^P'ific gravity 2.7. This corresponds to a weight of about 
 -5! pounds or 0.115 ton per cubic foot. The quantity of 
 staitium sulfate in the celestite rock is taken to be 81 
 pejent, which is the average amount in the 14 chemical 
 ailyses. 
 
 Table 2. Summary of measured sections of celestite rock. 
 
 Measured section 
 
 Distance 
 
 between 
 
 sections 
 
 (feet) 
 
 Thickness of 
 
 celestite- 
 
 bearing zone 
 
 (feet) 
 
 Thickness of 
 
 celestite 
 
 rock 
 
 (feet) 
 
 Percent 
 
 celestite 
 
 rock 
 
 
 800 
 
 900 
 
 1,300 
 
 3,250 
 
 100.0 
 
 80.0 
 
 372.0 
 
 410.8 
 
 62.0 
 
 11.0 
 
 20.0 
 
 111.0 
 
 112.6 
 
 4.4 
 
 11.0 
 
 
 25 
 
 Section 4 
 
 29.8 
 
 Section 5 .. 
 
 27.4 
 
 
 7.1 
 
 
 
 In calculating the reserves, it was assumed that be- 
 tween 250,000 and 300,000 tons of celestite rock is pres- 
 ent to a depth of 50 feet to the east of the last exposures 
 on the Jasper claim. For the area of good exposures on 
 the Jasper and Redfire claims, the average thickness of 
 celestite rock is taken as 110 feet. If an average thickness 
 of only 10 feet is allowed for the 2,900 feet between the 
 westernmost good exposure on the Redfire claim and 
 section 6, the total reserves to a depth of 50 feet would 
 amount to about 1,500,000 tons of celestite rock or about 
 1,200,000 tons of strontium sulfate. On the other hand, 
 if it is assumed that the celestite rock maintains an aggre- 
 gate thickness of 110 feet for an additional 1,800 feet 
 west of the last good exposure on the Redfire claim, and 
 then decreases to the thickness exposed in section 6, the 
 reserves to the same depth would amount to about 2,500,- 
 000 tons of celestite rock, or slightly over 2,000,000 tons 
 of strontium sulfate. The true value no doubt lies between 
 these two extremes. If the deposit should extend in depth 
 for as much as 500 feet, which seems not at all unlikely, 
 the total quantity of celestite rock could well exceed 
 10,000,000 tons. 
 
 The relative proportion of celestite rock to sediment 
 in the celestite-bearing beds is at the maximum value of 
 nearly 30 percent in section 4. However, this value would 
 not be the average grade of material mined. There are 
 a number of relatively thick zones within the celestite- 
 bearing unit that contain no celestite or only negligible 
 amounts, and these could easily be avoided in mining. 
 Elimination of the three principal barren zones in sec- 
 tion 5, which are 24, 35, and 91 feet thick, increases the 
 relative amount of celestite in the remainder to 43 per- 
 cent. The subtraction of four other barren zones 16.5, 
 12.2, 11.1, and 9.8 feet thick increases the proportion of 
 celestite rock in the remaining 211 feet of beds to 53 
 percent. In section 5 there are 12 units from 5 to 29 feet 
 thick totaling 123 feet in which celestite is present in 
 excess of 75 percent. Similar figures hold for section 4 
 and the area in between. 
 
 The average grade of the celestite rock, based on the 
 14 analyses quoted above, is 81 percent. In general the 
 celestite is purest where it is thickest and most massive. 
 Probably the richest zones will generally contain stron- 
 tium sulfate in excess of the average. Certainly they will 
 not carry less than the average, for the analyses represent 
 more closely a sampling of variations in grade and color 
 rather than a weighted sampling based on grade. 
 
48 
 
 Special Report 32 
 
 REFERENCES 
 
 Baker, C. L. (1911), Notes on the later Cenozoic history of the 
 Mojave Desert region in southeastern California : California 
 Univ., Dept. Geol. Sci. Bull. 6, pp. 333-383. 
 
 Gardner. D. L. (1940), Geology of the Newberry and Ord Moun- 
 tains, San Bernardino County, California : California Jour. 
 Mines and Geology, vol. 36, pp. 257-292. 
 
 Hewett, I>. F., Moore, B. N., Callaghan, E., Nolan, T. B., Rubey, 
 W. W., and Schaller, \Y. T. (1936), Mineral resources of the 
 region around Boulder Dam: U. S. Geol. Survey Bull. S71, 
 197 pp. 
 
 Merriam. J. C. (1919), Tertiary mammalian faunas of the Mojs 
 
 Desert: California Univ., Dept. Geol. Sci. Bull. 11, pp. 438-5: 
 Moore, B. N. (1935), Some strontium deposits of southeast* 
 
 California and western Arizona : Am. Inst. Mm. Met. Eng. Te 
 
 Pub. 599, pp. 1-24. 
 Tucker, W. B., and Sampson, R. J. (1930), Los Angeles & 
 
 division : California Jour. Mines and Geology, vol. 26, pp. 202-3: 
 Tucker, W. B., and Sampson, R. J. (1943), Mineral resources 
 
 San Bernardino County, California : California Jour. Mines a 
 
 Geology, vol. 39, pp. 427-549. 
 
 
 74750 2-53 2M 
 
 printed in California state printing office 
 
BSfiW&L 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 GEOLOGICAL SURVEY 
 
 grophic bose ffom J.0 Lewis, July 31, 1911 
 
 SECTION A-A 
 
 
 
 ' "Toe 
 
 : ->: 
 
 .. 
 
 '* m ™_i rbr C 
 
 
 
 ""■ 
 
 mSM 
 
 SECTION C-C 
 
 SECTION D-0 
 
 
 
 
 EXPLANATION 
 
 Terroce deposits 
 
 Contoct 
 Indefinite contoct 
 
 ', red sondstone ond cloys, 
 reccio.Trs, soil beds with 
 
 (Giant breccia) 
 
 Fault, showing dip 
 Proboble toult, or fault 
 
 plunge of oxis (Dost 
 approximately loc< 
 dotted where cone 
 
 Syocl.ne, showing troce of 
 oxiol plane. (Dashed where 
 opproiimately located; 
 doited where concealed) 
 
 Strike ond dip of beds 
 
 Q Cr T « 'vWRTgc 
 
 
 
 
 GEOLOGIC MAP OF CELESTITE DEPOSITS NEAR THE SOUTHERN END OF DEATH VALLEY 
 
 SAN BERNARDINO COUNTY, CALIFORNIA 
 
 
 i 
 
 •>5>.:- 
 
 sr;S„. i '■■ -.'mi I 
 
 C.I&* 
 
 
 i Cordell Ourrell ond A C Dol 
 
DIVISION OF MINES 
 OLAF P. JENKINS, CHIEF 
 
 STATE OF CALIFORNIA 
 DEPARTMENT OF NATURAL RESOURCES 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 GEOLOGICAL SURVEY 
 
 Topography by Cordell Durrell and A.C.Daley, November 1944 
 
 Geology by Cordell- Durrell and A. C. Doley, November 1944 
 
 SPECIAL REPORT 32 
 PLATE 2 
 
 EXPLANATION 
 
 Terrace gravel 
 
 /////////// 
 
 Clay, limestone, tuff beds 
 
 Calcareous tuff bed 
 
 Strontiamte bearing clays 
 
 showing individual 
 
 strontianite beds 
 
 Sandstone ond conglomerate 
 
 Contact 
 Indefinite contact 
 
 i 77 
 
 Fault, showing dip 
 U,upthrown side; 
 D.downthrown side 
 
 Fault, proboble or 
 location uncertain 
 
 Concealed fault 
 
 Strike and dip of beds 
 
 GEOLOGIC MAP OF THE ROSS STRONTIANITE DEPOSIT, MUD HILLS, SAN BERNARDINO COUNTY, CALIFORNIA 
 
 Contour interval 10 feet 
 Datum is approximate sea level 
 
DIVISION OF MINES 
 QLAFP. JENKINS, CHIEF 
 
 STATE OF CALIFORNIA 
 DEPARTMENT OF NATURAL RESOURCES 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 GEOLOGICAL SURVEY 
 
 SPECIAL REPORT 32 
 PLATE 3 
 
 SECTION A-A 
 
 SECTION C-C 
 
 SECTION B-B' 
 
 Note! Location of sections shown on Figure 12. 
 These sections prepared by stadia survey. 
 
 Geology by Cordell Durrell and A. C. Daley, December 1944 
 
 STRUCTURE SECTIONS, EAST END OF MUD HILLS, SAN BERNARDINO COUNTY, CALIFORNIA 
 
 2400 FEET 
 

 
 
 
 
 
 
 
 
 
 
 
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 .ond green cloy, thin limestone 
 loyers, and white and groy tuff 
 
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 White colcoreous tuff 
 
 Green and groy futfoceous sondstone 
 and conglomerate with thin algal 
 limestone 
 
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 green clay 
 Gray tuff bed 
 
 Yellow ond green cloy, thin-bedded 
 sandstone at too 
 
 Alternoting thin-bedded green 
 ond gray sandstone, green 
 ond buff cloy with sondy 
 limestone, ond limestone near 
 the top and bottom 
 
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 nodules 
 
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 ai 
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 2 
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 3 » - 
 
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 White rhyolite tuff 
 
 Sandstone, tuff, limestone and cloy 
 
 Mossive brown bentonite 
 
 Thin-bedded sondstone and 
 green clay 
 
 11 
 
 1°- 
 
 
 
nivlSION OF MINES 
 
 Ri af Tj ENKINS, CHIEF 
 
 STATE OF CALIFORNIA 
 DEPARTMENT OF NATURAL RESOURCES 
 
 \ ■ 
 
 ■%fe£$W& 
 
 EXPLANATION 
 
 tamte bearing beds 
 
 M 
 
 conglomerate, Tlit, white colcoteou 
 
 toff; Ttjsr.strontionite-beoring 
 
 sond stone 
 
 indefinite contact 
 
 Fault, shewing dip 
 
 Conceded fault 
 Strike and dip of be< 
 
 O' 
 
 +- 
 
 ^BPP>* "''I'^I^SIIiillSlI I 
 
 mmmr 
 
 Geology by Cordell Durrell ond A. C Daley, November 194 
 
 GEOLOGIC MAP OF THE SOLOMON STRONTIANITE DEPOSIT 
 
 MUD HILLS, SAN BERNARDINO COUNTY, CALIFORNIA 
 
DIVISION OF MINES 
 OLAFP. JENKINS, CHIEF 
 
 STATE OF CALIFORNIA 
 DEPARTMENT OF NATURAL RESOURCES 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 GEOLOGICAL SURVEY 
 
 SPECIAL REPORT 32 
 PLATE 6 
 
 ' 1 
 
 SECTION A-A' 
 
 SOUTH 
 3400'- 
 
 SECTION B-B 
 
 SOUTH 
 3400'- 
 
 SECTION C-C 
 
 NOfiTH 
 - 3400' 
 
 EXPLANATION 
 
 Terroce grovels 
 
 To, upper cloys including some 
 sand; Tut, gray tuff bed 
 
 ; r,., . 
 
 Upper sfronfionite- bearing beds 
 
 Yellow lominoted cloy with 
 
 thin limestone layers 
 
 SECTION D-0' 
 
 Lower stronfionife - beonng beds 
 
 Tts, tuffoceous sondstone ond 
 congiomerote, Tts t, white calcareous tuff; 
 Ttssr, strontianite- bearing sandstone 
 
 Geology by Cordell Durrell ond A. C. Daley, November 1944 
 
 Contoct 
 indefinite contact 
 
 STRUCTURE SECTIONS, SOLOMON STRONTIANITE DEPOSIT 
 MUD HILLS, SAN BERNARDINO COUNTY, CALIFORNIA 
 
 Fault, showing relative movement 
 
Umsion of mines 
 
 K f P. JENKINS, CHIEF 
 
 EXPLANATION 
 
 + 
 
 ESTIMATED VOLUME PERCENTAGE QF 
 STRONTIANITE ROCK IN OUTCROPS 
 
 
 \ 
 
 Ik 
 
 X 
 
 2 
 
 
 ; 
 
 \ ' '•: 
 \ 
 
 " ' i v. 
 
 \ 
 \ 
 \ 
 
 
 .._ 
 
 
 Amount indetermmote 
 
 LIMITS OF STR0NTIANITE-6EARING BEOS 
 
 \ 
 
 \ 
 
 \ 
 
 
 
 Upper strontionite-beonng beds 
 containing 10% or more by uotume 
 
 tl 
 
 il 
 
 Upper strontianite-bearing beds 
 of strontionrte rock 
 
 r 
 
 Lower strontmnite-beoring beds 
 
 i 
 
 Ex. 
 Excluded areos within outer limits 
 of lower stfonfionite-beoring bed 1 
 
 
 NOTE-. The most southerly limit is 
 fixed by outcrops or faults 
 
 
 Contact 
 
 
 indefinite contact 
 
 
 Fouit, showing dip 
 
 Survey by Cordell Durrell and A C Dole 
 
 AP SHOWING ABUNDANCE OF STRONTIANITE, SOLOMON STRONTIANITE DEPOSIT 
 MUD HILLS, SAN BERNARDINO COUNTY, CALIFORNIA 
 
DIVISION OF MINES 
 OLAF P. JENKINS, CHIEF 
 
 STATE OF CALIFORNIA 
 DEPARTMENT OF NATURAL RESOURCES 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 GEOLOGICAL SURVEY ' 
 
 Topography by the Metropolitan Water District of Southern California 
 
 Geology by Cordell Durrell and A. C. Daley, April 1945 
 
 Tb""^ ^"""- M — •-*- ■■ ■ '■ :'.■ '.'• ■ S ea level 
 
 l — I I — IE 
 
 Contour i nterval 200 feet 
 Datum is sea level 
 
 SECTION A- A' 
 
 SPECIAL REPORT 32 
 PLATE 8 
 
 EXPLANATION 
 
 Qal 
 
 Alluvium 
 UNCONFORMITY 
 
 mm 
 
 Lacustrine sediments 
 
 
 Rhyolite welded tuff 
 UNCONFORMITY 
 
 >P 
 
 illiTO j:;:::;; 
 
 Andesite 
 
 Basalt tuff, etc. 
 UNCONFORMITY 
 
 
 
 - 
 
 
 
 * * * * J 9 r ,%* 
 *** + *< 
 
 
 H < 
 
 i o: 
 
 
 Granite 
 
 
 a 3 
 
 CL 
 
 Contact 
 
 
 1 n 
 
 F 
 
 definite conta 
 
 ct 
 dip 
 
 
 + 55 
 suit, showing 
 
 
 Fault, probable or 
 
 
 location uncert 
 
 am 
 
 
 Concealed fault 
 
 Strike and dip of beds 
 
 Horizontal beds 
 
 General direction of dip 
 
 Mines and mineral deposits 
 
 5 Miles 
 
 GEOLOGIC MAP OF THE SOUTHEASTERN PART OF THE CADY MOUNTAINS, SAN BERNARDINO COUNTY, CALIFORNIA