Characteristics of the Boundary Between the Castile and Salado

Home , Castile Formation, Delaware Basin, Eastern New Mexico, Salado Formation

Gharacteristicsofthe boundary between the Castile and SaladoFormations near the western edge of the Delaware Basin, southeasternNew Mexico by BethM. Madsenand 1mer B. Raup,U.S. Geological Survey, Box 25046, MS-939, Denver, C0 80225

Abstract 1050 posited in the DelawareBasin of southeast New Mexico and west Texasduring Late Per- Permian The contact between the Upper mian (Ochoan)time. In early investigations Castile and Salado Formations throughout and SaladoFormations were un- the Delaware Basin, southeastNew Mexico /-a(run,ouo the Castile differentiated, and the two formations were and west Texas,has been difficult to define EDDY / aou^r" because of facies chanqes from the basin called Castile by Richardson (1904).Cart- center to the western idge. Petrographic wright (1930)divided the sequenceinto the studies of core from a Phillips Petroleum i .,/ upper and lower parts of the Castileon the Company well, drilled in the westernDela- -r---| ,' . NEW MEXTCO basisof lithology and arealdistribution. Lang ware Basin, indicate that there are maior (1935) the name "Saladohalite" Perotf,um introduced mineralogical and textural differences be- ,/ rot company "n for the upper part of the sequence,and he and Salado Formations. / core hole'NM 3170'1 tween the Castile the term Castile for the lower part The Castile is primarilv laminated anhv- retained of the drite with calciteand dolomite.The Salado ( of the sequence.Lang placed the base DELAWARE BASIN Formation is also primarily anhydrite at the SaladoFormation at the base of potassium location of this corehole, but with abundant (polyhalite) mineralization. This proved to layers of magnesite.This magnesiteindi- be an unreliable marker becausethe zone of catesan increaseof magnesiumenrichment mineralization occupies different strati- in the basin brines, which later resulted in graphic positions in different areas. Lang the deposition of magnesium-rich potash (1939)then proposedthat the boundary be- deposits within the SaladoFormation else- TEXAS wliere in the basin. A breccia zone at the top of the Castile Formation shows evidence of massive recrystallization, which indicates a break in sedimentationand pos- 50 KILOMETEFS sible subaerial erosion. This breccia zone 0 30 MiL€S Alsoin this issue probably representsan unconformity along the western edge of the basin between the LowerCretaceous strata Castile and SaladoFormations, which has FIGURE 1-Index map showing location of the been recognizedby other workers. Phillips Petroleum Company core hole. Dashed undersouthern High Plains P.6 Iine shows the westem edge of the Delaware Basin. Mineralparagenesis, Introduction structure,and "ore-shoot" ern New Mexico. The core hole, NM 3170- The contact between the Upper Permian geometryat the U.S. Castile and Salado Formations in the center 1, was locatedin the SWt/+SWllqsec.21,T263, of the Delaware Basin of southeast New R25E,(Fig. 1). Coring beganat 108ft below Treasurymine P. 10 contin- Mexico and west Texas has been defined by the surfacein the SaladoFormation, HarryMcAdams State Park P.12 several authors on the basis of maior litho- ued through the CastileFormation, and ter- minated in the underlying Lamar Limestone Abstractsfrom 8th annualMineral logic differences between the two forma- p.17 tions. In the center of the basin, where the Member of the Bell Canyon Formation at a Symposium Salado contains numerous beds of halite and depth of 7,230ft. This core provides a rare Service/News p.20 significant potash deposits, the contact has opportunity to examine the Castile-Salado p.24 A Staffnotes been placed at the base of a prominent an- contact, which is not seen in outcrop. hydrite bed that overlies the thick laminated description of the upper part of the Castile anhydrite sequence of the Castile Formation. Formation, the lower part of the SaladoFor- Gomingsoon Toward the edge of the basin, however, both mation, and the contactbetween the two for- formations are primarily anhydrite, and the mations is presented. Textural and UpperDevonian-Lower Mississippian two contact between the two formations is not mineralogical differences between the conodontbiostratigraPhY formations indicate a significant change in obvious. This paper attempts to define the Scanningelectron microscope study of contact at the west edge of the basin on the the environments of deposition for the two basis of mineralogical and textural differ- formations. authigeniczeolites ences of the anhydrite beds in the two for- Geomorphicdevelopment of CitYof Previous investigations mations observed in one core hole. Rocks,Grant County In 1969 Phillips Petroleum Company drilled The Castileand SaladoFormations are part an exploratory hole for sulfur in southeast- of a marine evaporite sequencethat was de- tween the Castile and Salado Formations dicate that deposition was in fairly deep water, in the center of the Delaware Basin repre- should be at the baseof a prominent anhv- well below wave base. Detailed studies by sentsthe filling of a deep basin with chemical drite marker bed, which hd hter named tlie Dean and Anderson (1978,1982)indicate thit sediments of progressively higher salinity. Fletcher Anhydrite Member of the Salado the salinity of the water in the Delaware Ba- The ratio of anhydrite to calcite(or dolomite) (Lang, 7942).The Fletcher,however, can not sin increased during the deposition of the in laminated beds of the Castile increases be traced throughout the basin and is not Castile Formation. This salinity increase is upward, and halite, which is sparsein the recognizableat the location of this Phillips indicated bv: 1) an increasein the amount of lower Castile,becomes plentiful toward the drill core. anhydrite in the anhydrite-calcite couplets top. The SaladoFormation represents a con- from the base upward, and 2) an increase tinuation of the generalincrease in salinity Geologic setting upward in the number of interbedded halite of brines in the basin; it is primarily halite The evaporitesof the Castileand Salado beds. with significant amounts of sylvite, carnal- Formations were depositedin a basin that The Salado Formation. which overlies the lite, and polyhalite and minor amounts of was initially quite deep. Regionalstudies by anhydrite. Udden (1924),Lang (1935),Adams g9!aj, The core hole described in this report was and King (1947)suggest that the water depth drilled along the western edge of the Dela- at the beginning of Castile deposition was ware Basinwhere the evaporitesare mostly about 500m. Anderson and Kirkland (1966) anhydrite, with somecalcite, dolomite, gyp- and Anderson et al. (1972)showed that very tile and Salado lithologies interfinger in the sum, and magnesite.Figure 2 showsthe lith- thin laminationsin the Castile,which are center of the basin. The work of Lowenstein ologies of the upper part of the Castile composedof distinct coupletsof anhydrite (1982) indicates that the Salado Formation Formation and the lower part of the Salado and calcite (occasionallywith minor dolo- was deposited from very saline brines, un- Formationin the Phillipscore hole. The brec- mite), can be identified and correlatedover der shallow water conditions, with occa- cia zone at the top of the CastileFormation wide areasthroughout the DelawareBasin. sional periods of desiccation. is also shown. Suchwell-preserved delicate laminations in- In summary, the Castile-Salado sequence Petrography Petrographicexamination of thin sections and polished core sections and scanning electron microscopestudies were made of severalsamples collected through the Castile Top ol core and SaladoFormations. Mineral identifica- tion was by x-ray diffraction.A description of the rocks from these studies follows.

Salado Formaton

Castrle Formallon New AAexnc@ GEOLOGY EXPLANATION . . Scienceand Service volume 6 t\\\ 10, No. 1, February lggg \\\ Massrve anhydr le N\ \ \ Edrfor Deborah A Shaw Drafter: RebeccaTitus

F\5I Lamrnaled anhydr le Published quarterly by l\\.,.- New Mexico Bureau of Mines and Mineral Resources a division of New Mqico Institute of Mining & Iehnology i-vT; Breccrated anhydrlte BOARD OF REGENTS rL! -al Ex Officio Carry Carruthers, Gooernorof Nru Mexico _l Magnes le Alan Morgan, Supqintendentof Publiclnstruction Appointed Gilbert L Cano, Ples ,1985 1989,Albuquerque Lenton Malry, SeclTreas ,1985-1997, Albuquuque Robert O Anderson, 1987-1993,Roswell "o Donald W Morris, 1983-1989,Los Alamos l Steve Torres, 1967-7997,Socorro New Mexico Institute of Mining & Technology 120 Pr*ident Laurence H Lattman l 400 New Mexico Bureau of Mines & Mineral Resources Director Frank E Kottlowski Depul! Director George S Austin 130- Subscriptions:Issued quarterly, February, May, August, NovembeU subscription price $6 O0/calendaryear Editorialmatter: Articles submitted for publication should 450 be in the editor's hands a ninimum of five (5) months 140.- before date of publication (February, May, August, or November) and should be no longer than 20 typewrit- ten, double-spacedpages All scientific papers will be reviewed by at least two people in the appropriate field of study Address inquiries to Deborah A Shaw, Editor 150: ol Nm MexicoGeolo6y, New Mexico Bureau of Mines & 500 Mineral Resources,Socorro, NM 87801 Publishedas publicdomain, therelore reproducible withouL pet Botlom of core at 1,230 ft mission requested FIGURE 3-Core sample of typical interlaminated Soutcecredit FIqUTE 2-Lithologic column of the upper part anhydrite and calcite of the Castile Formation Ciculqtion: 1,600 of the Phillips PetroleumCompany core hbte 1NU Lighter layers in photo are anhydrite. Depth-750 Printef: U^ivercLty of New Mexico Printing Plant 3170-7), Eddy County, New Mexico. ft.

February 1988 Nm Mexico Geology Castile Formation composed of subhedral to euhedral crystals The Castile Formation, in this core, is com- that range in size from 0.01 to 0.15 mm. This posed predominantly of interlaminated light- anhydrite characteristically also has the "pile- gray anhydrite and light-brown, organic-rich of-bricks" texture. calcite (Fig. 3). In the upper part of the sec- Limestone-Calcite in the laminated brown tion, the anhydrite is interlaminated with limestone beds has an average grain size larger calcite and dolomite. Interspersed with the than calcite in the laminated anhydrite rock. laminated section are beds of massive, light- Calcite occurs as an interlocking mosaic of gray anhydrite and beds of pale yellowish- anhedral crystals that range in size from 0.03 brown limestone. Halite, which may have to 0.2 mm. The subtle lamination in some of been present in this part of the section, has the limestone is due to alternating layers of been leached out and is represented bv col- different crystal size (Fig. 7). In other parts lapse breccia cemented by clear selenite. of the limestone the lamination is due to Laminated anhydrite-carbonate rock- organic-rich partings that separate crystal Anhydrite in the laminated rock in the Cas- layers of fairly uniform grain size (Fig. 8). tile Formation (Figs. 3 and 4) is interlami- Breccia zone-The breccia zone at the top nated with both calcite and dolomite. Calcite of the Castile Formation consists of approx- is present throughout the Castile, whereas imately 154 ft of brecciated massive anhy- dolomite is present only in the upper third. drite, which is bounded at the top by the Anhydrite in the laminated rock is com- lowest occurrence of magnesite of the Salado posed of blocky, subhedral to euhedral crys- Formation and at the base by the last ap- tals from 0.01 to 0.15 mm. This is the so- pearance of laminated anhydrite typical of called "pile-of-bricks" texture (Fig. 5A). Within the Castile. The anhydrite rock of the breccia the groundmass of fine-grained anhydrite are interval is light gray and contains numerous a few larger crystals of anhydrite (Fig. 5B). veins of selenite and breccia zones cemented Calcite crystals in the laminated anhydrite by clear selenite (Fig 9). These rocks are rock (Fig. 4) range widely in size from 0.005 mostly free of carbonate. Figure 10 shows the to 0.05 mm and are anhedral to subhedral. initial stage of multiple generations of re- Dolomite crystals in this rock type (Fig. 6) crystallization of the breccia zone anhydrite. are very uniform in size and range from 0.01 In this section, fine-grained anhydrite (less to 0.03 mm. The crystals are subhedral to than 0.1 mm) is being replaced by coarser, (0.5-5.0 rounded, and appear light brown in trans- blocky material mm). This blockv mitted light. medium-grained anhydrite is, in turn, re- Massive anhydrite rock-Anhydrite in placed by very coarse, radial laths (Fig. 11). unlaminated, massive anhydrite rock is al- These laths, which form fans and spheru- most identical to the anhydrite in the lami- lites, commonly include fine-grained impur- nated parts of the section. It is light gray and ities. In some areas the laths form a dense interlocking mat of coarse-grained anhy- FICURE S-Photomicrographs of laminated an- drite. The overall appearance of this zone is hydrite rock from the Castile Formation A, Typ- that of an interval of collapse breccia and ical "pile-of-bricks" texture of anhydrite crystals massive recrystallization. There is no re- Plain light. Depth-750 ft B, A few large crystals maining evidence of original sedimentary of anhydrite in a matrix of smaller anhydrite crys- layering. tals. Crossed polarizers. Depth-1,130 t, : The brecciation in this zone is probably the result of removal of halite that was interbedded with the anhydrite at the top of the Castile Formation. Anderson (1981) docu- mented several breccia horizons within the Castile that he interpreted as resulting from the removal of halite. Solution breccias have been identified by Bachman (1984)between the Castile and Salado Formations in southern Eddy County, New Mexico, and the ad- iacent area of Texas.Bachman interpreted the solution breccias to be the result of dissolution of salt beds in the overlying lower Salado in either early Mesozoic or Cenozoic time. We believe that the dissolution of the halite occurred before the deposition of the Salado Formation. There is no evidence of collapse of Salado rocks into the breccia zone, which indicates that the brecciation was pre-Salado in age. This breccia zone is probably an unconformity, representing a period of subaerial erosion at the top of the Castile along the western edge of the basin. Both Adams

IiICURE6-Photomicrograph of Castileanhydrite FIGURE 4-Photomicrograph of interlaminated with a laminaof dolomitecrystals. The dark crys- anhydrite and calcite typical of the Castile For- tals of dolomiteare very uniform in sizeand sub- mation. Dark crystals are calcite. Plain light. hedral to rounded Plain light. Depth-667 ft Depth-750 ft

Nm MexicoGeology February 1988 (19t14)and Anderson (1978,I98l) advocated an unconformity at this horizon.

SaladoFormation The SaladoFormation consists of massive, very fine grained, light-gray anhydrite rock, mottled with streaksand wisps of white mi- crocrystallinemagnesite (Fig. 12).Thin section examinationof the magnesiticanhydrite showsthe anhydriteto be lessthan 0.01mm, equigranular,and anhedral (Fig. 13). This xenotropic anhydrite matrix containsirreg- ular patchesof coarseranhydrite ranging in size from 0.02-0.05mm (Fig. 14). The very fine grained magnesite appears in thin section as opaquestreaks and swirls in the anhydrite matrix (Fig. 15).A scanningelectron microscope(SEM) photograph shows that the magnesiteoccurs in smallclusters surrounding larger,blocky crystalsof anhydrite (Fig. 16,4.).Higher magnification of one of the clustersshows that they are formed of closely packed rhombohedralcrystals (Fig. 15B). ' 2OOpm $ Fracturesand small brecciazones, which ns were formed after the consolidationof the 8':i:,::,**ffi&,&{i* anhydrite rock, are cementedand filled by clearselenite. FIGURE 7-Photomicrograph of laminated Castile limestone. The subtle lamination is caused by al- Summary and ternating layers of calcite crystals of different size. conclusions Crossed polarizers Depth-1,221 ft The Castileand SaladoFormations in the DelawareBasin represent sediments that were deposited in an evaporite environment of steadily increasing salinity. The boundary betweenthe two formations,in general,rep- resentsa changefrom sulfate,carbonate, and some chloride deposition in the Castile, to depositionof chloridesand magnesium-rich potash mineralsin the SaladoFormation. FIGURE 9-Core sample of a breccia zone cemented by selenite from the breccia zone at the top of the Castile Formation Depth-291 ft

FIGURE 8-Photomicrosraph of laminated Castile limestone.The laminati6nis causedby thin partings of organicmaterial between the liyers oi calcite. Plain light. Depth-1,222 ft.

FIGURE 1O-Photomicrographof coarse,recrvs- FIGURE l1-Photomicrograph of coarse,radiating tallizedanhydrite from thi biecciazone at the top crystals of anhydrite from the brecciazone at the of the Casiile Formation. Crossedpolarizers'. top of the CastileFormation. Crossed polarizers. Depth-322 ft Depth-246 ft.

February 1988 Nm Mexico Geology Adams (19t14)recognized an unconformity salt dissolution in the northern part of the anhvdrite with somelavers of carbonate.The between the Castile and Salado Formations basin following the deposition of the Halite major difference between the Castile For- in the northern part of the DelawareBasin. III unit (upper halite) of the CastileForma- mation in this core,as compared to corefrom Correlations of acousticallogs and facies tion." farther into the basin, is the absenceof halite studies by Anderson (7978, 1981) support The Phillips core hole, on which this study that has been removed by dissolution.The Adams' interpretation. Anderson (1978,p. is based,was drilled at the westernedge of SaladoFormation in the core can be distin- 17) said that "there was an episodeof non- the Delaware Basin where both the Castile guished from the underlying Castile For- deposition,angular unconformity, and even and Salado Formations are now primarily mation on the basisof anhydrite characterized by major inclusionsof magnesite.The magnesite in this basin-edgefacies indicates an enrichment of magnesiumin the basin brines that later resultedin the depositionof magnesium-rich potash depositswithin the Sa- lado Formation elsewherein the basin. The top of the brecciazone in the Phillips core probably represents the unconformity, and perhaps the period of subaerialerosion at the top of the Castilethat was described by Adams (1944)and Anderson (1978,798I). This breccia zone in the core representsdis- solution of halite that resulted in brecciation and massive recrystallization of the anhydrite at the top of the Castilebefore deposition of the overlying magnesitic anhydrite of the SaladoFormation along the western edge of the basin. Contortion of the mag- nesitelayers, as describedfrom this core hole, probably resulted from slumping and differ- ential compactionof soft sedimentsthat were deposited over the irregular breccia surface at the top of the CastileFormation. Continuedon page 9

FIGURE l2-Core sample of anhydrite from the FIGURE 14-Photomicrograph of fine-grained an- Salado Formation mottled with white, verv fine hydrite with irregular patches of coarser anhydrite grained magnesite.Depth-'I42 fl from the Salado Formation. Partiallv crossed Do- larizers. Depth-153 ft.

FIGURE 16-Scanning electron micrographs of magnesitic anhydrite of the Salado Formation. FIGURE 13-Photomicrograph of magnesitic an- Depth-153 ft A, Clusters of magnesite crystals hydrite from the Salado Formation. Magnesite ap- FIGURE 15-Photomicrograph of very fine-grained surrounding larger blocky crystals of anhydrite pears as opaque streaks. Crossed polarizers. Salado anhydrite with dark-gray streaks and swirls (An). B, Closer view of a cluster of rhombohedral Depth-109 ft of magnesite Plain light Depth-118 ft magnesite crystals

Nm Mexico Geology February 1988 terrane (Fig. 8). The valleys formed mostly AcrNowlrpcMENrs-Sherman Galloway, Continuedtrom page 5 before Ogallala deposition primarily by private consultant,and personnelat the New AcxNowlroGMENTS-Thanks are ex- westward headward erosion acrossthe Mexico StateEngineer Office in Roswell,New tended to the Phillips Petroleum Company southern High Plains(Seni, 1980). Mexico, provided usefu-linformation and well for providing the core for this study. Tech- Significantly, Lower Cretaceousreservoirs log data used to construct maps and cross nical reviews by Roger Anderson, George also dischargesome ground water into sectionsin this report. Funding for the in- Bachman, Marc Bodine, Jr., Walter Dean, bounding reservoir systems.In the Causey- vestigation came partly from the TexasState Robert Evans, Robert Hite, Frank Kottlow- Lingo area of Roosevelt County, New Mex- Legislature and Texas Water Development ski, Charles Jones,James Markello, Charles ico, basalLower Cretaceoussand and gravel Board in Austin, Texas,in coniunctionwith Maxwell, Richard Snyder, and Samuel reservoirs are truncated in downdip areasby a larger regional study of Lower Cretaceous Thompson, III, and editorial commentsby coarse-grained"valley fill" Ogallaladeposits, reservoirs under the southern High Plains of |ames Barker were very helpful. Special permitting cross flow into the Ogallala sys- both Texasand New Mexico.Figure and text thanks are extended to Mary H. Miller who tem. Vertical leakage into the underlying review arecredited to Tommy Knowles, Chief, made substantivecomments on an earlyver- Dockum Group (LateTriassic) also occursat Water Data Availability and Studies Section, sion of the manuscript. isolatedlocations, particularly where coarser- TexasWater Development Board; Bill Stone, References grained fluvial-deltaic facies exist in upper New Mexico Bureau of Mines and Mineral Adams, J. E.,1944,Upper PermianOchoa series of Del- parts of the red bed sequence(Granata, 1981). Resources;and RobynWright and Barry Kues, aware Basin,west Texasand southeasternNew Mexico: Wells completedin Lower Cretaceousres- Department of Geology,University of New American Association of Petroleum Geologists Bulle- ervoirs under the southern High Plains of Mexico. tin, v.28, pp. 1595-1.625. New Mexico provide ground water for var- Anderson, R. Y., 1978,Deep dissolution of salt, northem New Mexico:Sandia Laboratories report, Albuquerque, ious surfaceuses. Widelv snacedover much References New Mexico,107 pp. of the study area, welli drawing from the Ash, S. R., 1963,Ground-water conditions in northem Anderson, R. Y., 1981,Deep-seated salt dissolution in the reservoirs are thus far noticeably concen- Lea County, New Mexico: U.S. GeologicalSuroey, Hy- Delaware Basin, Texasand New Mexico; ln Wells, S. trated only in the Causey-Lingo area of drologic Investigations Atlas HA-62, 2 sheets. G., and lambert, W. (eds.), Environmental geology and Brand, J. P., 1953,Cretaceous of Llano Estacadoof Texas: hydrology in New Mexico: New Mexico GeologicalSo- Roosevelt County, where they supply water Bureau of EconomicGeology, University of Texas(Aus- ciety, SpecialPublication No. 10, pp. 133-145. for both crop irrigation and domestic use. tin), Report of Investigations No. 20, 59 pp. Anderson, R. Y., Dean, W. E., Jr., Kirkland, D. W., and Undevelopedparts of the reservoirsystems Cooper, J. 8., 1,960,Ground water in the Causey-Lingo Snider, H. L, 7972, Pemian Castile varved evaporite showing potential for supplying additional aea, RooseveltCounty, New Mexico:New MexicoState sequence,west Texasand New Mexico: GeologicalSo- Engineer, TechnicalReport 14, 51 pp. ciety of America Bulletin, v. 83, pp. 59-86. surface water to the southern High Plains Fisher,W. L., and Rodda,P.U.,1969, Edwards Formation Anderson, R. Y., and Kirkland, D. W., 1965,Intrabasin exist in northern Lea County, particularly (Lower Cretaceous), Texa-dolomitization in a car- varve correlation: Geological Society of America Bul- where relatively thick basal Lower Creta- bonate olatform svstem: American Association of Pe- letin, v. 77, pp. 241256. ceous sands and sandstonesoccupy ero- troleurn Geologisti Bulletin, v. 53, pp. 55-72. Bachman,C. O., 1,9U,Regional geology of Ochoanevap- Granata,G. E., 1981,Regional sedimentation of the Late orites, northern part of Delaware Basin: New Mexico sional scour channels that are cut into the Triassic Dockum Grouo. west Texasand easternNew Bureau of Mines and Mineral Resources,Circular 184, underlying Dockum Group (LateTriassic). Mexico: Unpublished M.S. thesis. Universitv of Texas 22 PP' (Austin),199 pp. Cartwright, C. D., Jr., 1930,Transverse section of Per- Mount, J. R., Rayner, F. A. Shamberger,V M., Jr., Peck- mian Basin, west Texasand southeasternNew Mexico: ham, R. C., and Osborne,F. L., Jr., L967,Reconnais- American Association of Petroleum Geologists Bulle- sance investigation of the ground-water resourcesof tin, v. 14, pp.969-987. the Colorado River basin, Texas:Texas Water Devel- Dean,W E., andAnderson,R. Y., 1978,Salinitycycles- opment Board,Report 51, 107pp. evidence for subaqueousdeposition of Castile Forma- Rayner, F. A., 7963,Water from the Cretaceoussands in tion and lower part of SaladoFormation, DelawareBa- Cochran County, Texas;ln The crosssection newsletter: sin, Texasand New Mexico; in Austin, G. S. (compiler), High Plains Water District, Lubbock, Texas,pp. 3-7. Geology and mineral deposits of Ochoan rocks in Del- Reeves,C. C., Jr., 1970,Drainage pattern analysis,south- aware Basin and adjacent areas:New Mexico Bureau ern High Plains, Texas and eastern New Mexico; in of Mines and Mineral Resources,Circular 159,pp. 15- Mattox, R. B., and Miller, W. D. (eds.), Ogallalaaquifer 20. symposium: International Center for Arid and Semi- Dean,W. E., and Anderson,R. Y., 1982,Continuous sub- Arid Land Studies. SoecialReoort No. 39, TexasTech aqueous deposition of the Permian Castile evaporites, University,Lubbock, pp. 58-Zl. Delaware Basin, Texasand New Mexico; in Handford, Seni, S. J., 1980, Sand-body geometry and depositional C. R., Loucks,R. G., and Davies,G. R. (eds.),Depo- systems, Ogallala Formation, Texas: Bureau of Eco- sitional and diagenetic spectra of evaporites--{ore nomic Geology,University of Texas(Austin), Report of workshop: Society of Economic Paleontologistsand Invesiigations No. 105, 36 pp. Mineralogists Core Workshop No. 3, pp. 324-353. Weeks,J. 8., and Gutentag,8.D., 19U, The High Plains King, R. H.,1947, Sedimentationin PermianCastile sea: regional aquifer-geohydrclogy; in Whetstone, G. A. American Association of Peholeum Geologists Bulle- (ed.), Ogallala aquifer symposium II: TexasTech Uni- tin, v 31, pp.470-477. versity, Water ResourcesCenter, Lubbock, pp. 625. Lang, W 8., 7935,Upper Permianfomations of Delaware Basin of Texasand New Mexico:American Association of Petroleum GeologistsBulletin, v. 19, no. 2, pp.262- 270. Lang, W. 8.,1939, Saladoformation of the Pemian Basin: American Association of Peholeum Geologists Bulle- tin, v.23, pp. 1.559-1572. Lang, W. 8., 7942, Basal beds of Salado Formation in Fletcher potash core test, near Carlsbad,New Mexico: American Association of Petroleum Geologists Bulle- tin, v.26, no. I, pp. 63-79. Lowenstein, Tim, 1,982,Primary features in a potash evaporite deposit, the Permran Salado Formation of west Texasand New Menco; in Handford, R. C., Loucks, R. G., and Davies,G. R. (eds.),Depositional and diagenetic spectra of evaporites-a core workshop: So- ciety of Economic Palmntologists and Mineralogists Core Workshop No. 3, pp. 276-304. Richmdson,G. 8., 1904,Relnrt of recomaismce in Trans- Pecos Texas north of the Texas and Pacific Railway: University of Texas(Austin), Mineral Suroey Bulletin FIGURE 8-Structure contour map showing the 9,1.79pp. altitude of the top of Lower Cretaceousstrata un- Udden, J. A.,1924, Laminatedanhydrite in Texas:Geo- der the southern High Plains of New Mexico. logical Society ofAmerica Bulletin, v. 35, pp. 347-35L

New Meico Geology February 1988