Waste Isolation Pilot Plant

Compliance Certification Application

Reference 86

Brokaw, A.L., C.L. Jones, M.E. Cooley, and W.H. Hays, 1972. Geology and Hydrology of the Carlsbad Potash Area, Eddy and Lea Counties, New Mexico, USGS-4339-1, Denver, 'CO, U.S. Geological Survey.

Submitted in accordance with 40 CFR g194.13, Submission of Reference Materials. UNIm STATES DBPAEmNI QP GBOIMlfCAL SURVEY .

LONG-TERM REGULATORY COMPLIANCE

GEoLaY m HH)ROLaY OP TaE CARSBAD PurAsH AREA, EDDY IZA mS; mXICO

Arnold L. Broh, C. L. Joner, M. E. Cooley, and W. H. Eayr

Open-f i le report 1972

Prepared under Agreement No. AT (40-1)-4339 for the Division of Waste Management and Training U.S. Atomic Energy Commission I \

Thir report ir prelinimry and ha not been edited or reviewd for conformity with U.S. Geological Survey rtadrdr or nmoclature.

CONTEUTS--Conc la, ued Page Page wining meth&s------64

Trlassic and Cretaceous depositloo------. 26

Tertiary and Quaternary deposition--r------27

2 9

28

30 32

33

Geology of salt deposits--0choan Series------34

Castile Formtion------3 5

39 Appendix A, Reprint of Permian basin potash deposits,

47 south-western United States by C. L. Jones------(in pocket) 5 1

5 3

pecos niver------5 3

Water-bearing units overlying Salado Formation------5 3

59

Strata underlying Salado Formation------6 1

6 2

History of miming------.--..-..------6 2

l,ocat&m of mines------.------..------ua------6 3 Methods of prospecting and explorrtiorr------64 ILLUSTRATIONS--Continued ILLUSTRATIONS Page Page Figure 9.--1sopach map showing thickness of Salado Figure 1.--Map of the vicinity of the potash mines, Formation------southeastern New Mexico------5 45 10.--Columnar sections of the McNutt potash zone----- 2.--Generalized stratigraphic column at Gnome (in pocket) 11.--Columnar sections of Rustler Formation------50 site and description of lateral var iat ions---- 18 12.--1sopach map shoving thickness of Rustler 3. --Generalized geologic crosr sect ion from south Formtion------to north through the vicinity of the Gnome (in pocket) 13.--Map showing height bf water table above i site and the potash mines------19 1 contact between gypsiferous residue and 4.--Map showing distribution and structure of salt-bearing rock in Salado Formation------pre-Quaternary rocks, Carlsbad potash area---- 29 55 14.--Map rhowing generalized distribution of I 4A.--Geologic structure crosr sections A-A' and I E total dissolved solids in well water in the B-B'------(in pocket) 4 rock6 overlyin8 the Salado Formation------5.--Structure contour map of Carlsbad potash 57 15.--Map shwing generalized distribution of area------(in pocket) I chloride in well water in the rocks 6.--Map showing distribution of sylvitic potash werlying the Salado Formation------58 deposits, Carlsbad potash area------4 1 16.--Map of mine workings, Carlsbad potash district-- (in pocket) 7.--Columnar sections of Salado Formation------(in pocket) 17.--Map showing holes drilled for potash, Eddy 8.--Map showing structure contours of contact and Lea Counties, New nexico------between gypsiferous residue and salt-bear ing (in pocket)

rock in Salado Formation, and water table 18.--Map showing oil and gas wells in part of Eddy and Lea Counties, New Mexico------(in pocket) or potentimetric contours in formations

overlying the Salado Formation------19.--Map of oil and gas fields in southeastern New Mexico------TABLES GEOLOGY AND HYDROLOGY OF THE CARLSBM POTASH AREA, - Page EDDY AND UZA COUNTIES, NEW HEXICO BY Table 1.--Generalized section of rocks a~dsedhente .\rnolli L. Broluw, C. L. Joner, M. E. Cooley, and U. U. Hays of latest Permian (post-Salado) and younger age------3 2

2.--Evopor ire minerals in rylvite u.ad polyhrlite & 8 The potash mines of southeastern New Mexico are in a sparsely deposits in the Carlsbad potosh area------populated area 15-30 miles east of Carlsbad. Topographic relief is lw, surface drainage poor, and collapse features c-on. The climate 3.--Hydrology of geologic formations overlying is semiarid. saladO pOrmat~a------C ,in pocb.erj Sadhentary rocka attain thicknesses of more than 20,000 feet and 66 range in age from Ordwician to Quaternary. The area includea the 4.--Shaft location index, Carlebad district------northern end of the Delaware basin and the largely buried Capitan Reef. 12 The basin catains as arch aa 13,000 feet of Permian strata. The 5.--Rocks exposed in the Gnome shaft------oldest exposed rocks are of Late Permian aga, but drilling has provided much data on the buried older rocks. The principal structures are broad 6.--Nomenclature of oil- and gar-producing tones, gentle features related to late Paleozoic sedimentation: the northern southeastern New Mexico------76 Delaware basin, l rhelf north and west of the basin, and a central barin platform to the eart. These rtructures were tilted eastward before Pliocene time, bve been inactive rince, and oar show a general eastward dip of less than 2..

The ralt deposits are in the Ute Permian Ochoan Series composed of a thick aalt-bearing evaporite laver part (Csrtile, Salado, and Rustler Formations) and a thin non-ralt-bearing upper part (Dewey Redbeds). The Castile Forution consists largely of interlaminated gray anhydrite and bravnirh-gray limestone, but includee much rock salt. It is about 1,500-1,600 feet thick along the southern edge of the potash area; it thins northward to about 1,000 feet near the margin of the Delaware basin .Rd tongues out in the southernmost parts of the northwest shelf. All the salt is concentrated in a thick middle member which lies 200-300 feet above the bare of the formation.

The Salado Formation, the main salt-bearing unit of the potash area, ranges in thickness from about 1,900 feet in the routh to about 1.000 feet in the north. The forution is characterized by thick persistent units of rock salt alternating with thinner units of anhydrite and polyhalite. Thin reams of claystone underlie the anhydrite and polyhalite unit, and there are a few beds of sandstone and siltstone at The potentimetric and water-table contours outline a series of large intervals. The Salado Formation is divided into three informal ground-water ridger and troughs which are imposed on the regional units: a lower and an upper salt member, generally free of sylvite and southward to southwestward pattern of ground-water movement. A large other potassium and magnesium evaporite minerals; and the HcNutt potash southwestward-plunging ground-water trough extends from Halaga Bend zone. generally rich in these minerals. northeastward roughly through Nash Draw to beyond the mining area in the vicinity of Laguna Plata. Another much smaller trough is east and The Rustler Formation mostly anhydrite and rock salt, thins from southeast of the Project Gnome rite. 300 to 400 feet in the southern part of the area to about 200-250 feet in the northern part. Some dolomite is present in the upper and lwer The Salado Formation has an intergranular porosity and parts of the formation, and thin to thick units of sandrtone and shale permeability that ranger from low to virtually none. Locally, fractures are interbedded at long to short intervals. and solution openings impart a spotty formational permeability. In I the potarh mining area, the Salado Formation is dry except for water in I The Dewey Lake Redbeds at the topof the Ochoan Series consirt of reddish-brawn siltstone and f ine-grained sandstone. The formation ir the leached zone at the top of the formation and small pockets of water I or water and gas encountered occasionally during mining. 1 250-550 feet thick in the potash area. I 1 The Cambrian to Permian sedimentary rocks underlying the Salado Three main hydrologic units control the ground-water hydrology of Formation contain water of brine comporition and are under high artesian the Carlsbad potash mining area: the Pecor River, the water-bearing These rocks are not expored in the potarh mining area but lie strata overlying the Salado Formation, and the Capitan Limestone and pressure. deeply buried throughout much of southeartern New Mexico and western other water-bearing strata underlying the Salado. The distribution and Texas. Zn the potarh mining area the elevations of the potentiametric development of large dissolution features, particularly in the Nash surfacer of different zone. of there rocks range from a few feet to a Draw and Clayton Basin areas, exert a major effect on the occurrence few hundred feet above or below the land rurface. axd mwement of the ground water. The Pecos River receives nearly a11 -* of the ground-water outflow from the area. Most of that outflow reaches the Pecos near Halaga Bend. INTRODUCTION

The main water-yielding units overlying the Salado Formation are The U.S. Geological Survey, on behalf of the Atomic Energy the basal solution breccia zone and the Culebra Dolmite Hellber of the 1 Rustler Pormation, the Santa Rosa Sandstone, and the alluvium. The Commirsion, har sumoarired the available geologic and hydrologic basal solution breccia zone is the hydrologic unit most significant in the solution of halite, from the upper part of the Salado Formation. information on the Carlrbad, U. Hex., potrrh area. The purpose of this The easternmost extent of evaporite solution in the potash mining area is roughly at the camon boundary between Ranges 30 and 31 E. The sumary is to furnish the Atomic Energy Commission with data that would formatione above the Salado Formation seem to be connected hydrologically and can be considered a ringle multiple aquifer system. Solution be ureful to them in their evaluation of variour geologic formations activity and associated collapse, subeidence, and fracturing have increased the overall permeability of the rocks and the interformational for the disposal of radioactive wartea. The project was started on movement of water in the aquifer system. April 1, 1972, and canpleted on June 30, 1972. Ground water in the formations above the Salado moves generally southward and southwestward acrors the potash mining area toward the In preparing this report we have drawn liberally on published Pecos River. Although the total amount of ground water discharging to the Pecos River not known, it has been estimated that 200 gallons is reports and on unpublished file data of the U.S. Geological Survey. Ye per minute enter the river from the basal rolution breccia zone. have benefited fran the full cooperation of R. S. Fulton, Regional Mining Supervisor, U.S. Geological Survey, Carlsbad, N. Hex., and

D. M. Van Sickle, Regional Geologist, U.S. Geological Survey, Roswell,

N. Hex. We had the pleasure of discussing the objectives of this project

with Donald Baker, Director, New Mexico Bureau of Mines and Mineral

Resources, and with Prank Kottlwski and Roy Poster, also of that

organization. Discussions and underground trips with William Stanley

of the U.S. Potash Company, and Karl Ehlers of the Duval Company were

also very helpful in our work.

GEOGRAPHY

Location and population

The potash mines of southeastern New Mexico are in eastern Eddy

County and westernmost Lea County. Most of the mines lie along a north-trending line 15 miles east of the city of Carlsbad and

25-45 miles north of the Texas border (fig. 1). Two mines are 10 miles

farther east.

The area is sparsely populated. Populations given here are.

ertbates for Jan. 1, 1972 (Rand McNally and Co.. 1972). Eddy County has a population of 39,800 and Lea County 48,800. Other than Carlsbad

(20,500), the only cities of 1,000 or larger population within SO miles of the mines are Hobbs (25,800), Artesia (10,300). Lovington (8,900),

Eunice (2,600), Ja1 (2,600), and Loving (1,200). Except for widely scattered ranch and farm houses, the only habitations within 20 miles of the mines are in Carlsbad, Loving, and the s~uallcoamunities of bodiec of perennial surface water within 14 miles of any potash mine.

Halaga, Otis, LOCOHills, and Haljamar. Population is highly dependent The northern edge of Salt Lake is 4 miles couthwest of the International on the petroleum and potash industries, and any large increase other Mineral and Chemical Corp. mine. Other lakes (or "lagunas") east of than through possible expansion of these industries seems improbable. the Pecos contain water only after heavy rains. Lakes H31i11an and

Avalon and the smller reservoir on the river at the east edge of Surface water Carlsbad are 15 miles or more fran the nearest mine. The Pecos River, which rises in northeastern New nexico and ultimately joins the Rio Crande at the Hexican border, is the only Toponraphy '

through-going perennial stream in this area. Here and farther south The topography of the area (fig. 1) falls easily into four large

the Pecos receives almost a11 the surface discharge and at least the divisions: the eastern Cuadalupe Mountains and its foothills; the greater part of the subsurface discharge from the area. Surface drainage High Plairu; isolated areas of lar hills, principally south of Carlsbad

from most of the area is poor. The only significant continuously and southwest of Eunice; and widespread pediments and alluvial plains,

flowing tributary of the Pecos is Black River, south of Carlsbad. The north, east, and southeast of Carlsbad. Collapse features locally abundant small intermittent Streams generally drain into depressions modify the topography throughout the region. produced by sand dunes or by solution subsidence where the water Cuadaluve Mountains.--The Cuadalupe Mountains form a moderately evaporates or sinks into the subsurface. Of the intermittent streams, dissected plateau, gently inclined to the northeast (Hayes, 1964). the longest is in Monument Draw, which drains southward along the eastern South of Carlsbad the mountains are bounded abruptly on the southeast edge of Lea County. It is rare for such generally dry channels to carry by the Reef Escarpment, the face of an exhumed Permian reef that bordered continuous flars of water, as the runoff from thunder showers ordinarily the Delaware basin. This striking topographic and stratigraphic sinks into depressions in the floor. feature emerges from the subsurface near Carlsbad. It becomes steeper

The Pecos River, small recervoirs behind two dam between Carlsbad and higher southwestward fraa Carlsbad and culminates in Cuadalupe Peak and Loving, and a small part of Salt Lake, east of Loving, are the only (8,751 feet), 50 miles from the.city. Northwest of Carlsbad, the the Pecos River and south and vest of the High Plains, the area near margin of the mountains is far less spectacular; the northeastern slope Artesia from the river vest to the foothills of the Gudalupe Mountains, there descends gradually to the pediments that flank the Pecos River. and the area south of Carlrbad between the Pecos River, the Gypsum High Plains.--The High Plains are a large remnant of the depositional surface on top of the Pliocene Ogallala Formation. The surface of the Hills, and the Beef Escarpment. The basic form of almost a11 the ground surface of the region ir plains is remarkably even and slopes east-southea~tabout 15 feet per erosional and conaiats of Pleistocene pediments and partial pediments mile. It Is underlab by a thick layer of caliche, which is mantled that have been modified to varylog deprees. in places by thin soil. West of Hobbs and Lovington, the plains are Nearly a11 the surface east of the Pecoa River, includiqg the vicinity of the potash mines, sharply bounded by a aouthveat-fachg eroaioa.1 acarp, 100-300 feet high, known aa Mescalero Ridge. South of Hobbs, the boundary is only is a pediment or group of coalesced pediments of probable early Pleiatocene age (Morgan and Sayre, 1942, p. 35). vaguely defined (Nicholson and Clebsch, 1961). This surface van

Lw hills.--The Gypsum Hills, a group of lw rounded hills eroded modified during and since its formation by solution-collapse features. fram gypsiferous Permian rocks, occupy much of the area between the Pecos It has been dissected locally by atre-, and large parts of it are

River and the Reef Escarpment, 20 milea aouth of Carlabad. Farther mantled by shifting or stabilized aand dunes. north, small hills locally project abwe the piedmont surfaces flanking Along the Pecos Bluer and west of the river, the surface is youoger the escarpment. In Lea County, two lw ridges, north and west of San than that to the east and co~iItaof a complex of three terraces that ccmmonly rire like broad stepa from the river to the foothills or Slmon Sink may preserve outlying remnants of the High Plains surface lw to the escarpment of the Guadalupa Mountains (Fiedler and Nye, 1932, (Nicholson .ad Clebsch, 1961).

Pediments and alluvial plains.--her most of the area shova on p. 10-12). The upper two terrace. are interpreted as remnant* of Pleiatocene pediments (Uorberg, 1949, p. 472; Horgaa and Sayre, 1942, figure 1, the ground aurface has lov relief and slopes gently P. 35). vhereaa the lweat and youngeat terrace was produced by (20-40 feet per mile) avay from the borders of the Guadalupe Mountains and the High Plaina tovard the Pecos River or locally tward Black River moderate entrenchment of the river and its major tributaries into Mrrau discontinuous alluvial plains. and Monument Draw. Included, in general, is a11 the large area east of Collapse features.--Collapse features produced by subsurface -Climate solution are varyingly camnon throughout the region. They are most The climate of nearly the whole region is semiarid. The average abundant east of the Pecos River in parts of the widespread old annual precipitation ranges from about 12 to 13 inches near the Pecos pediment. Solution occurs where unsaturated circulating ground water River and Ja1 to almost 16 inches at Hobbs. In the Cuadalupe passes through or along the contacts of layers of salt, gypsum, Mountains, precipitation rises to about 22 inches near the sumit. anhydrite, or, to less extent, carbonate rock. These soluble rocks Most precipitation is from local thundershwers that occur from predominate in the Ute Permian Ochoan Series, which underlies a11 the June to October. The variation in the yearly total is large. area east of the Pecos River. The relative humidity in the region is lw. Minters are mild

The collapse features range in size from small sinks to depressions with little snow, and a-ers are warm. The average July temperature many miles long. Indeed, the present course of the Pecos River was near Carlsbad is a little over 60. F. Uindstorms, mainly in the

probably determined by a train of coalesced Pleistocene sinks captured spring of the year, m~ybe severe.

by a~headward-working tributary of the Rio Grande (Morgan and Sayre, Industry 1942, p. 37). Other conspicuous expressions of ground-water solution Mineral production in Eddy and Lea Counties has been nationally include the subsidence of the floor beneath the alluvirn of the significant, and, as of 1%7, Lea County ranked first in the State Roswell-Artesia basin to as much as 140 feet belaw the bedrock outlet of in value of production. The petrolern, gas, and potash industries the basin south of Artesia (Morgan and Sayre, 1942, p. 37), the several have dooinated the econooies of the two counties for several decades. abrupt changes in flaw in the Pecos River within 20 miles north of All yearly production values given belaw are abstracted or derived Carlsbad (Morgan and Sayre, 1942, p. 37), Nosh Draw and Clayton Basin from data coanpiled by Stotelmeyer (1969). close to the potash mines east of Carlsbad,and San Sinon Sink southwest Production values of crude petroleum, natural gas, natural-gas of Eunice. liquids, and rutural gasoline totaled $72.4 million in 1967 in Eddy

County. Of this, $54.8 million was crude petroleum. In Lea County, the production value of crude petroleum alone, largely from the central Agriculture over most of this dry region consists solely of the and southern parts of the county, was $247 million in 1967. grazing of cattle and sheep. Irrigated farms concentrated along the Exploration is active and The production is gradually increasing. Pecos River near Artesia and south of Carlsbad account for a large is particularly spurred by increasing demand for natural gas. Sanger part of the total agricultural income. There is dry farming on the and Saultz (1971, p. 1039). in discussing exploration in 1970 in the nigh Plains. district of West Texas and eastern New Mexico, stated that the Tourist dollars are an important part of the local economy.

Delaware basin, "...still in the early stages of its exploratory Carlsbad Caverns, WhitC Sands, and other nearby natural features draw

history, continued to be very active and to have the greatest potential.. . many thousands to the ares each year. Deep gas reserves from Devonian through Ordovician (Ellenburger) continue to be of prime considerat ion." Accesp The vicinity of the potash minea readily accessible by highway, The potash mines east of Carlsbul are the principal source of is railroad freight, and acheduled air service. potash available within the United States and constitute a11 of the The mines are served by production in New Mexico. The total value of potash produced since hard-surface State or federal highways that provide easy year-round access Carlsbad. 1932 is $1.75 billion. In 1966, the value was well over $100 million Era Federal highways extend from Carlsbad in several directions. (Stotelmeyer, 1969). Since then, foreign competition haa greatly Spur lines of the Santa Fe Railroad serve the mines, connecting via Carlsbad with the -in line at Clovis, N. Her., about reduced production, and same mines are closed. Decline in the industry 180 miles to the northeast. resulted in reduction in the population of Carlsbul from 25,500 in 1960 Carlsbad has scheduled air service to El Paso, Albuquerque, and Dallas-Ft. Worth via Texas International to an estimated 20,500 in 1972 (Band McNally and Co., 1972). Large Air1 ines reserves of potash remain, and the future of the industry seers to . depend on demand, which is influenced greatly by the extent of foreign STBAT 8CllAPHY competition. The potash mines in southeastern New Hexico (fig. 1) are in an

area of great stratigraphic significance. Sedimentary deposits ranging generally overlain by Ordovician strata that lapped northwestward in age from Ordovician to Quaternary attain total thicknesses exceeding onto a positive area in northern New Mexico and Colorado. Locally, 20,000 feet. The area includes the northern end of the Delaware basin, near the eastern boundary of Lea County, late Paleozoic uplift a Late Permian depositional trough with Pennsylvanian and earlier Permian caused erosion of a11 older Paleozoic rocks, and Permian strata lie antecedents. The edge of the basin is comnonly defined as the front of directly on basement. the largely buried Capitan Reef. As much as 13,000 feet of Permian

atrata Was deposited within the area of the basin, which constitutes the Pre-Permian Paleozoic deposition The oldest Proo Ordovician through Pennsylvanian time, marine sediments most complete succession of the Permian in North America. * rocks exposed in the area are of Late Permian age, but drilling has accumulated slowly but fairly continuously in the southeastern corner

provided abundant information on still older rocks. of New Mexico. Deposition was in and marginal to broad, nearly flat,

The text that follows is largely limited to brief discussions of subsiding basins that were northern arms of the Ouachita trough. This

sedimentary environments, gross thicknesses, relations between trough passed through Oklahoam and central and trans-Pecos Texas and connected with open sea in the vicinity of the present gulf coast or stratigraphic units, and occurrences of petroleum. Lithologic descriptim~ I

and thicknesses of individual units are shown on the accompanying the cast of southern California. In Early Pennsylvanian time. the

illustrations. initial rise of a median ridge that was to be known as the central basin platform of Permian time (fig. 1) divided an earlier very vide basin Precarpbrian basement into the ancestral Delaware basin and the Midland basin farther east. The depth of the Precambrian basement ranges from as little as The various Paleozoic basins were areas of especially active subsidence 7,000-8,000 feet below the surface in the northwestern corner of the whose surfaces were generally lower than those on the more stable area and easternmost Lea County to more than 20,000 feet in southernmost shelves, plat forms, or arches bounding them. Total deposit ion was Lea County. Drill data from scattered locslities indicate that the thickest in the central part of the Delaware basin where subsidence vas basement consists of granitic, metasedimentary, metavolcanic, and greatest, but the deposits of sme time intervals, notably the volcanic rocks (Plawn, 1954 and 1956. p. 25-29; Hayes, 1964, p. 5; Pcnnaylvanisn Period, vere thickeet on the margins. Poster and Stipp, 1961, p. 17, 19-29). The Precambrian rocks are The subaidence that defined the anceatral Delaware basin in The total thickness of the pre-Permian sedimentary rocks is Pennsylvanian time accelerated in Early Permian Uol fcampian t ime and 5,000-5,500 feet in the hediate vicinity of the potash mines. The cont inued at a high rate througl;' Guadalupian time. rocks thicken southeastward to more than 7,000 feet in southern During ouch of this interval, the basin extended a few tens of miles northwest of Lea County and thin northwestward to about 3,300 feet near the middle the late Cuadalupian limits defined by the Capitan reef of that age. of the northern edge of'Eddy County. The rocks are predwiluntly The subsiding basin wua covered to varying depths by nmrine water and shale and carbonates (fig. 2). Rocb of Misaissippi.~~and received deposits of ahale, fine-grained aandstone, and dark-colored Pennsylvanian age are dominantly ahale in the central parts of the baai~ llertone. The rock column for this interval (fig. 2) ia representative of deposition and carbonates along the edges. Middle 0rdovici.n and of the type of depoaition in the northern part of the basin. Light-colored touer Pennsylvanian aandetones a few hundred feet thick occur in the shallaw-water carbonates generally bounded the basin on the shelves to vicinity of the potash mines and the Gnome rite. the west and north, and the platfora to the east. Rocks of OrdovicLn, Silurian-Devonian, and Pennsy1vaai.a age Reefs or banka of less coheaive akeletal material very coamonly composed the basinward form important petroleum reservoirs beneath the central baain platform edges of these carbonates (fig. 3), and submarine talus formed steep and the northwest shelf (fig. 1). Production from rocks of these ages slopes deacendiq to the floor of the baain. Aa the reefa grew upward, in the northern Delaware basin is widely scattered and interest is some also grew basinward, overriding their talua. increasing in deep exploratory drilling there. Close behind the reefs and banks, the contemporaneoua ahelf rocka

Permian deposit ion I (fig. 3) consiat of bedded dolomite, aubordinate .mounts of llmeetone, i Uolfcampian. Leonardian. and Guadalupian Series.--Over a large ares shale, and aandstone, and locally a little anhydrite. The gradational in the general vicinity of Carlabad, the total thickness of the contact between shelf and reef facies,.like that between reef and baain

Uolfcampian, tcolurdian, and Cuadalupian Ser ias is 8,000-9,000 feet. faciea, c-only traluects bedding as it rises in the section The section thins gradually northward from the mines. The rocka are tasinvard. Parther back of the reefs, the dolomite of the upper part of I noted for remarkably complex latefal changes in facies. the Cwdalupian Series (the Artesia Croup) and, to much less extent,

that of the lower Cuadalupian and Leolurdian Series tends to give way

Increasingly to aahydrite, formed in shallow evaporative lagoons.

17 OPEN FILE--1972 BROKAW AND OTHERS DEPARTMENT OF THE INTERIOR CARLSBAD POTASB , UNITED STATES GEOLOGICAL SURVEY NEU MEXICO ui I r FORMATIOM Sw mt- (WHERE :: DESCRIPTION eBa oz uxu moo OIF FERENTIATEDI 5 '

I a

and, clay, and randrtona, uncantormoble on redbod*.

Malnly antydrin, gmarally intarlaminatad with calclta In crntrol and lamar

falrly uniform within boaln. OPEN FILE--1972 BROKAW AD OTHERS

DESCRIPTION

Sand, cloy, ond wndetone, unconformable on redbede.

(lolnl~ hollte and orglllaceour hollte. There rocke, thinner loyere of rulphote

Mainly ontydrlm, generally interlominoted with colclte In central and lower

ioir\y uniform within Barln.

reef (Coot See0 Reef) or bonk ond then, behind the reef, lnla dolomite,

basin, apparently little accumulated in the reef and back-reef areas. The reefs bounding the northern edge of the Delaware barin Probably rather late in Castile time, the basin was filled to the extent progressed from a position north of the present potash wines, in that a thin tongue of aohydrite extended locally across the bounding Leo~rdianand early Cuadalupian time, to a position within the mining reef and onto the shelf. area in late Guadalupian time (fig. 3). Elrevhere on the margins of The uppermost part of the Castile At the end of intertongues reefward into basal halite of the Salrdo Formation (Jones, the basin there was a similar basinward progression. 1954, p. 108-109; Jones and Madsen, 1968, pl. 2). Cuadalupian time, the Capitan Reef almort canpletely encircled the The Salado Formation ir one of the principal deposits of halite basin, restricting southern access to the sea and setting the stage on the North American conti'nent. for basins1 evaporite deposition. It overlies the Castila conformably in the Delaware basin and extends over the Capitan Reef to the north The northwest shelf, north of the Delaware basin, and the central basin platform, east of the basin, have been important producers of and east, far beyond the limit. of the area here described. Whether the Salado once extended west of the basin ir unknown. petrolemi from Permian rocks. Extemive pools in sandstone ad The Salado sea was, in general, even more saline than the sea of Castile time. carbonates of the Artesia Croup and the San Andrea Formation are lacking a rhield of carbonate reef., it received, however, co~iderable concentrated in a belt inmediately above and behind the buried Capitan fine clastic sediment. halite deporits are generally 1esa pure Reef, but there has been significant production from almost a11 parts Its than those of the Castile. of the Wolfc.mpian, Leo~rdian,and Cuadalupian section in various areas After widespread deporitida of the Salado salt, the sea water on the shelf and platform. Established pools within the northern frehened somewhat, and Wydrite yain dominated deposit ion during Delaware basin are more scattered and are principally in sandstorres of Rustler time (table 1). The Rustler Formtion is very largely the Delaware Mountain Croup. coextenrive with the Salado in this &re&. Ochoan Series.--The floor of the Delaware basin in early Och~n In the subsurface of the northern Delaware basin and of the shelf to the north, the Rustler time is generally estimated to have been at least 1,200 feet belw the While many appears to be conformable to the Salado (Jones, 1954, p. 110; 1960, top of the Capitan Beef, which almost encircled it. p. 12), from which it is commonly separated by a layer of solution hundreds of feet of Castile Formation evaporites accumulated in the breccia, discussed later in this report. T&le 1.--Generalized section of rocks ad sediments of latest Penin tuost-Salado) and vounger a~ein the northern Delaware basin and on its northern and eastern uruins

Description Variationti in Series Pomtiorr Thiche~s System (feet) thickness and distribution

Light-bram to pale- Dune rand, as much as roddish-brm par- 60 feet thick, dis- tially rtabilized continuously cwer- fine- to medium- in$ much of area be- Dune sand, 0-300 Holocene :,..-., . tveen Pecos River and alluvium, -. .' grained dune rand. Alluvial sand, silt. High Plains. Thick playa and gravel. Playa alluvium limited to deposits, vicinity of rivers. and deposits of minly travertiDL revorked alluvium and dune sand. Travertine as sprLng deposits.

Unconf ormit y

Uainly roddish-mange Discontinuour and high- or pale-red very ly variable in thick- fine to medim- ness wer luge area grained sand d southvest of High silt. bully acme Plains .nd svbly gravel ud clay and, out of Peco~River, in Eddy County and Gaturn 0-300 uric-ly. gyps- Pleirto- .Id fresh-vater probably Lea County. cene(?) limestone. Bedding Hostly less than c-ly obscure 100 feet thick. and discorrtinuour . nostly capped by caliche . bcal high permeability.

- ---- Uacaaformit)

rmh~c~.--(;cnrrmlizc? eeccion of rock. and sed~~e~t~of latest Pe mlaa oat-Salado) and younger aue 1n the northn

Sy~tem Set ies Porm~tion Thickness Description Variations in (feet) thickness and distrBut ion

Chiefly uhite, gray, Underlies High Plains and reddish-brova ad much of ~eacounty fine-grained sand, farther south. Pro- vhich locally has Tertiary Pliocene Opllala 0-300 ulcite cement. bably absent from Eddy County except for Subordimate gravel, northeast cotner. silt, and clay. Lenticular, discon- t inuous bedding. Mainly upped vith caliche. Highly permeable. =Unconf ormity Reddish-brw end Thickest in eastern greenish-gray clay- Lea County; erosion- stone 8ad subor- ally thinned west- Triassic Upper Chinle( ?) din~teauats of vard to vedge out 0-1,200 Tr iass ic reddirh-brown rilt- near eastern edge of stone and fiae- Eddy County. I grained sandstone. Sow secondary i gypsum. Lw per- meability. ---- -i .-.----- Table 1.--Generallied sectim of rock6 and sediments of latest Penla (~06t-sal.do) and vower age the uorther~Delwre basiu and on it8 nathera and eutmur~lna--Coatlnued

Dessript ion Variations in Series Formation Thickness thickness and Systca (feet) distribution

minly pale-reddish- Absent near and west brm. pale-red of Pecon River and and ay f to locally farther tart. medim-gralncd comnonly cross- sat. ROSA 0-300 strat ified rand- Trlarslc Upper Lcrues of Triarric stone. pebble colrgloQcr- ate. Lou1 thin layers of reddish- broun siltstone d claystone. High loul perrea- bility. ~oconfarmitr- Reddish-or-ge to Halnly 200-300 feet reddish-bran! fine- thick in vicinity of grained randrtone, Crime eite and pot- siltrtone, and ash mines; locally shale., Saadstorrc absent. Thins grA- 0-400 and riltrtone are dually northward. Permlaa Ochw Drvey Uke Absent vent of Pecoc Redbedl c-nly clayey. This lmirution River. and small-scale cross 1-ia4t ion caorr. Permea- bility generally lau . \ -

fable I.--~rneraltred recrion of rock6 md mediments of late~tPermian (poet-galado) a~dvounner scIn the northern Delaware basin and on its northern and eastern mrgins--Conthued

Sya tern Series Forort ion Thicknesr Description (feet) Variations in t hiclmess and dirtrlbutiao

l~~tly.nbydrite. Thin~veryp.d~lly Conriderable aalt, northward. Thick- C-ly silty or ness rawer from clayey, occurring 200 to 500 feet ia in cmtr.1 put of vicinity of Gnome Dclav~ehsin ad site and miner due PermIan tends to 10- out Ochorrn Pus t ler 0-500 to varisble rub- . at mrgior. Two surface solutioa, dolamite layerr, a which fncreases baral raadrtme, westward. .nd several thinner layers of fine elastics are vide- rpreul. bin quifer in C.rl8b.d area. Ute in Early Cretaceous time, a shallw sea advanced from the The Rustler represents the last Permian saline sea and the upper south and covered southeastern New Mexico. It soon withdrew le~ing layer of a remarkable sequence of predominantly evaporite rock of Ochoan behind a thin deposit of limestone and sandstone. The only remnsnts age.- The entire sequence is as much as 3.5M bet thick in the northern of this deposit in the vicinity of the northern Delaware basin are part of the basin. The thickness drops rapidly to about ln500 feet on in very -11 are- in easternmoat Lea County. in the western Gypam the shelf near the northern potash mines and decreases more gradully Hills. and perhaps on the crest of the Reef Escarpment (Hayesn 1964. farther north. p. 38). After the sea withdrew. the Dewey Lake Bedbeds were depmited on

broad- - mudflats over the former sea bed. The appearance of medium-scsle Tertierv and Quaternary deposition

cross luiution in sandy leues in the upper put of the formatloo No early or middle Tertiary deposits are known to be present in

probably indicates a gradual chwe to fluvial cditims (Vine. 1%3. the region. Cretaceous deposition was followed by broad uplift in

p. 23) an the fW1 episode in the 10- complex hiatory of the Permian the vicinity of the Guadalupe Mountains and brther north and by

dapos it ion. erosion of Cretaceous urd ~riasricrocks to form a surface of lw

Except for dolomite and mndstone laye" in the Rustler Forutia. relief sloplop gently aut and southeaet. In Pliocene the, this the Ochoan Series generally h~ rery la, permeability. The little 011 surhce extended frm near or within the present Guadalupe Mountain

produced from lower Ochoan evaporites apparently escaped from area and from the uplands north of that area southeastward into Texas.

underlying sandstone (Mumn 1965. p. 2148). It was mantled by the Eluvial Ogallala Formtion, whose upper surface of deposition is fairly well preserved on the High Plaim today. Triassic and Cretaceous depositioq There are no definite remnants of the Ogallala west of easternmost Fluvial deposition resumed in Ute Tri~sictime. when the 6-1. i' Eddy County, but gravels la the Pecoe valley and on high parts of the Rosa Sandstone and the finer grained redbeds of the ~hinle(?)Forwtim ! C~&alupeMountaiw hve been interpreted as belonging to this formed on flood plains in a very larp area over and beymd the formtion (Brett and Horberg, 1949). borders of the Delaware buin. The Juruic Period is not rep"mnted ; of erosional rem~alof Host authors believe that the Pecos valley was formed in by deposition in this region and was a t qutarmr~the. after Oaallala deposit ion. Solutim subsidence. the Triassic rocks west of the basin. coalescing of solution depressions by surface erosion and further

solution, and headward erosion by the Pecos River and its tributaries , ! -.- .. 1- IU contributed to the fortwition of the valley. After much erosion, a -.-ID --. period of aggradation in the valley mantled the slopes and filled

depressions with the Gatuna Formation, whose sediment is largely of

local origin. Renewed downcutting by streams and subsurface solution

and resultant subsidence have continued to the present and h8ve

been accompanied by intermittent local accumlatioar of pediment ad

terrace alluvium and playa deposits.

General features

The rocks in the general vicinity of the potash mines (fig. 1)

are for the most part little deformed, and they have been tectonically

stable since Tertiary time. The principal structural units are br-d

features related to late Paleozoic sedimentation: the northern

Delaware basin, the shelf north and west of the basin, and the central

basin platform to the east (fig. 1). The 6-11 part of the Guadalupe

Uountains included in the area, though topographically high, is

structurally part of the shelf. Tbe major structures were tilted

gently eastward mainly during pre-Pliocene time. The tilt produced

a general eastward dip of no more. than 2. (f ig$,.,g.@&nd-.5). Delaware bas in apparently reprerentative in it8 scattering of open fold., dmer,

~h~ ~~l~~~~~basin war first defined in Early pen-^^^^^^^^ time* 8-11 faultr, which be, in part, of tectonic origin. Deep-reated faultr with more tho 20 feet of vertical displacement are rare if when an earlier very broad basin var divided by initial uplift of a not abrent there (Jonea, 1%0, p. 16). large median ridge that became the central basin platform of Permian Near the wertern edge of the 1I barin ad the prerent upper courra of the Black River, Cenozoic time. The barin rubrided relative to the bounding platform and toctonirm my be involved in a northve8t-trending ~onoclirulflexure. rhelf until Late Permian tbe, when itr hirtory ar an active structural i Kelley (1971, pl. 5) ahwed 600 feet of relief acrorr thir monocline feature ended. 1 I on the upper rurfaca of the Bell Canyon Formation. The form of the northern part of the barin, as daffned by Several minor high-angle faultr cutting the Cartile Formation in the rue part of contourr on the rurface of the Precdrian floor (Porter .nd stipp, i the barin and two inferred faultr at the northvertern edge of the 1961). ir a broad arymuetrical trough, trending north and plungi~g barin (Kellay, 1971, p. 48-51) are moat probably productr of rolution routh. The uir ir in central Lea County, roughly parallel to the ! rubridance. Subrutface rolution ha. produced many other minor faultr central bar in platform. The eartern rlope of the trough rirer rapidly 1 and nmerour local flexure8 in the near-surface rockr, ar well ar the to the platform, whereas the vertern dope ir much gentler. I ~.nyrink8 .ad larger deprar8iolu. A8 in any gradully rubriding barin, the older redirentr are 1 In addition, @mallrurficial dome. that are attributed to differential rolution of ralt or to downwarpad in a form like that of the barement floor, and the warping expanrion of anhydrite during hydration are numerour (Vine, 1960). dies out upward in the barin rection (fig. U). The Late Permian I The generally rirple aurface rtructure of the barin ir doubtlers Ochoan rocks and the Trhrric rockr expored in the barin today c'o not romewhat deceptive. reflect baainwide warping, ad their major structural feature ir the A fault zone in the Guadalupe Hountailu may have extended routheartward into the ventern edge of the barin, below regional eartvard rlope mentioned above. Thir rlopa ir 75-100 feet the younger monocline darcribed dove, and my have been active during per mile in proximity to the Gnome rite and the routharn potarh mines.

Dirruption of the regiolul rlope of the Ochoan and younger rock Hirrirrippian to Early Permian tire (Hayes, 1964, p. 42). Pennrylvanian ' deforution, for which there ir widerpread evidence in eartern Nev ir minor. The vicinity of the Gnaw rite and the routhern miner is lateral (Kelley, 1971, p. 44-48). Another buried member of this set Mexico and western Texas, mey be represented elsewhere in the subsurface, may pass inmediately southeast of Lake Hdiillan (Roswell Geological and rapid Early Permian subsidence of the basin was accompanied by Society, 1968, fig. 9). A long lw east-trending arch in Lste Permian widespread block faulting vithin it (Adas, 1965, p. 2144). rocks the Artesia-Vacuum arch, passes a little south of Artesia. It Notthwest shelf is at least largely the product of differential campaction over the The regional structural elope in that part of the shelf north Abo Reef of Early Permian aee.- and west of the Delavare basin (fig. I) is as much as 200 feet In the part of the Cuadalupe Hountainr included in the area per mile in the Cuadalupe nountains and generally no more than discussed, monoclines and folds are the prominent structures. A 100 feet farther east. In the vicinity of the northern potash mines, buried broad fold or arch of Lawardian and early Guadalupian age

this slope is interrupted locally by minor domes, folds, monoclinal trends northeast a little behind the present Reef Escarpment (Hayes,

flexures, and faults similar to etructural features described near 1064, p. 42-43). It apparently controlled the location of grwth the southern mines. A difference here is that sore of the dopes are of the Goat Seep and Cbpltan Beefs. Much later, probably duriw

probably of depositional origin, resulting from irregularities in Tertiary the, eonoclimal flexing contributed to the basinvard dips

Cubdalupian carbonate depositioa (notts, 1972). Nowhere, here or in the kte Permian rock of the escarpment. Other folds, on the

near the southern mines, are there,"strong or well-defined zones of ridge above the escarpmnt and a180 about 12 miles vest of Carisbad,

folding or faulting representing response to cmpressive or tensional are of early Tertiary or perhaps older age.

forces" (Jones and Madsen, 1968, p. 9). Other than minor surficial deforwtion related to solutioo ad

Beyond the vicinity of the mines, the shelf north of the basin hydration of evaporites, the entire shelf in this area appears to have includes a few more strongly expressed structural features. been stable in Quaternary time. . Several miles northwest of Artesia, a buried northeast-trending fault, offsetting Upper Permian rocks along a distance of about 30 miles, is 1 Central basin platform The central basin platform, whose western edge is included in probably part of a prominent set of northeast-treodiog shear zones that I the area discussed here, has an eventful history involving more extends far to the north. Hovement on these zones was initiated in I intense deformti- than that of the basin and shelf., Carboniferous or earlier time and my have been basically right latest nississippian or Early Pennsylvanian the, the area (fig- 4) ad, although they are largely covered by extensive dune

I deformed to an elevated emergent fold belt, trending north-northwert. 1 rand, caliche, and alluvi~ldeporitr, they are well known from the cwntlerr boreholer drilled in exploration for potasrium raltr and The belt ryhave been bounded by'high-angle faultr and ryhave a

horst rtructure (MMI~,1965, p. 2143). After rubmergence and petroleum. Exposurea of Ochoan evaporiter in the potash area are exceedingly deporition in Middle ~d part of Ute Pennrylvanien time, renewed poor for rtrat igraphic rtudier or any other invert igationr requir iog orogeny further elevated the area and "rbrpened, cwrerred. and faulted the foldr" (Hillr. 1963, p. 1737-1718). Uplift continuer precire knwledge of the camporition, sedimentary rtructurer, or thicknear of the three evaporite formations. rtro~glythrough Uolfcmpian time ad then rlwed. Since filling of Thin in true becaure of the conriderable lithic and rtructural changer that hve accompanied the Widlad and Delaware barinr in Ute Permian time, the platform hr extenrive evaporite solution and rcoav.1 by meteoric water@. been rtructurally stable. Solution of blite and other readily soluble raltr be been complete to depth. GEOLOGY OF SALT DEPOSITS--OMW seitxss of revaral bwdrad feat, and all anhydrite and other roluble calcim All the ralt deporitr in the Carlabad potuh area are in the raltr have been weathered to gyprum. The removal of roluble raltr Ochm Series of Ute Permian age. The Ochour conrirts entirely of har rerulted in A great reduction of formation thicknerrea and in

redimentary rockr, but it b.0 two distinct parto--. thick lower rection much rubridence adaccompanying brecciation of a11 reridual gyprup of ralt-bearillg evaporiter and a thin upper rection of red beda. The and overlying deporitr. Conrequently, the entire area of evaporite lwer rection includer, in arceding order, the Cartile, Salado, and outcrop in in reality a "regolith" liberally dented and creared by

Ruetler Formntionr, uherear the upper rection conrirtr entirely of numerous rinkr, fiarurer, and linear rolution valleyr. the Dewey Uke Redbedr. The Cartile Formation ir confined to the Delaware barin In the routhern half of the potrrh area and in knwn Cartile Formation The lower part of the Ochoan Series 1. reprerented in the Carlrbad only in the rubrurface (fig. 4A). The three younger forwtionr form potash area by the Cartile Formation. the prequternary bedrock acrora the greatert part of the area The Cartile war rumed and In the subsurface of the Carlsbad potash area, the Cartile defined by Richardson (1904, p. 43) to include several hundred feet of Formation ir readily divisible into three informal members. gypsum that overlies the Bell Canyon Formation and underlies the The tripartite subdivision includes a lower and an upper anhydrite member Rustler Formation at the surface in the western part of the Delaware separated by a thick salt member (fig. 4A). basin. Somewhat later, the interval reprerented by gypsum at the The three members are distinctive, conformable, and constitute laterally persistent surface vas found by drilling to consist of a much larger sequence of are rock units in the potash area and wer wide sectionr of the Delaware evapor iter in the subsur face, including mostly anhydr ite in the louer I basin. . parts of the evaporite sequence and mostly rock salt in the upper Near the mugin of the basin, however, the three members merge into single wedgelike mass of a+ydrite that rapidly thins put. For a time the tvo parts of the evaporite sequence vere classed a to a mrrw tque and extendr acrors the basin margin for a few miles as lover and upper members of the Castile, but they were considered

to be separate formations. Fimlly, LIng (1935) restricted the name before thinning out in the southern part of the northwest shelf. The lwer aohydrite member of the Castile Formation gradatiomlly Castile to the lover part of the sequence and applied the name Salado I overlies the Bell Canyon Formation in the Delaware basin, but to the upper part. Re8i01ullyB the criterion most c-ly used to I werlaps the Capitan Limestone along the urgin of the basin. differentiate one formation from the other is the predoaio.lrce of Within the area of overlap, the lover member of the Castile is presumed to anhydrite in the Castile and the predomimnce of halite in the Saldo. I The Castile Formation underlies the southern half of the potash die out abruptly, in part by pinchout against the Cspitan Limestone and in part by lateral uradation into lami~tedlimestone that grades in area at depths ranging from about 500 feet in the west to almost turn into wsive limestone of the Capitan. 3,200 feet in the east. The nearest outcrops of the formation are in The melPber ranger in thickness from 210 to 230 feet in the southern parts of the potash the Gypsum Hills in southern Eddy County, U. Hex., about 16 miles area, but thickens northward and attains thicknesses of 320-380 feet southvert of the potash area. In that area the Castile consists of a short distance fram the overlap of the Capitan Limestone. interlaminated white gypsum and dark-brownish-gray limestone and 1 The some laminated braunish-gray limestone and a little brown dolomite. predominant rock in the member is interlmimted gray anhydrite and brownish-gray llestone. A few beds of dark-gray and brwnish-gray Near the center of the Gypsum Hills the formtion dips beneath the limestone, a few inches to several feet thick, are persistent in the Salado Formation and gypsum gives way to anhydrite in the subsurface. lwer and middle parts of the member; some are practically of basinwide The middle member of the Castile Formation is a salt-rich lentil 700-800 feet thick in the southern part of the potash area, but thins that forms a widerpread, lithologically distinct rtratigraphic marker. northward and ir a8 little as 150-300 feet thick in the areas near

The member is 550-700 feet thick in the routhern part of the Carlsbad the margin of the Delaware basin where the underlying salt member is potarh area. but thickens northward and attain0 thicknerrer of thickest.

800-1,000 feet along a broad 2- to 3-mile-wide belt that parallel8 the The Castile For~~ationis overlain by the Salado Formation. The urgin of the Delaware basin. North of thin belt, the mambar contact between the two formations has been considered to be an terdnates, in part by lateral gradation to anhydrita and in part angular unconformity (Adams, 1944, p. 1608). Contrary to this by intertorrguing with anhydrita (fig. 4A). The member is predo~iluntly interpretation, subsurface studies in the Carlsbad potash area and elsewhere in the Delaware basin shw that the upper beds of the Castile rock salt. but it contains thin to thick layers of interlmiluted

anhydrite-linertone rock. The thiclust of there layers averages about grade laterally into, and intertongue with, the lover beds of the

100 feet, adit divides the member into two almost eqully thick Salado. In this truuitio-1 sequence, the Castile intertongues with

salt beds. Tbe lwer of the two bed8 ir free of intarlmlolted r~ccassivelyolder rocks of the Salado, causing a gradual stratigraphic descent in the top of the Cartile, which responsible for the decrease anhydrite-limestone layers, wherur the upper bed includes several of is

these layers, sama of which are 2-5 feat thick. in the thickness of the upper member of the Castile frm about 800 feet

The upper member of the castiia Forution is an anhydrite-rich in the mouthern put of the potaah area to about 160 feet and less in

unit that exhibits the most lithologic complexity. It coneirts uinly the central part of the area and then to 0 in the northern part.

of interlamiluted anhydrite-limestme; but ollrriva anhydrita and rock Salado Format ion ult are present in appre~iablemounts ad there are lasrar mounts Conriderable econaic significance is attached to the Salado of dolomite and wgnesita. The member include8 a northward-thinning Formation because it contains the potash deposits for which the tongue of mngnesitic anhydr ite that overlaps the Capitan LSmestoae Carlsbad area is well knom among geologists. The deposits are the aloq the mnrgin of the Delaware basin and extends a few miles into do~liluntsource of the potasrium salts mined in the United States, the northwert rhelf (fig. 4A). The mnin body of the member is and their wide extent suggertr that they will maintain this ranking for yearn to cane. Depooita containing aylvite (KC1)--the main

potaoaium mineral of econarmic importance--have been mined at

11 localitlea (fig. 1). but they underlie practically the entire

eartern half of the potaah area and extend eaatward beneath much of aouthweatern Lea County, N. Hex. (fig. 6). The Salado alao contairu many depoeita rich in polyhalite [K~C~~M~(SO~)~-~LI~O]that are extenoive and widely distributed but lack the econmic importance of the aylvitic depoaito. The polyhalitic and aylvitic depoaita are

fairly important elementa in the stratigraphy of the Salado Formation, and a apecial aection of thin report (appendix A) aumarizea ame detaila of their distribution and geblogy.

The Salado Formation, named by La- (1935), in the oldeat unit in the Ochoan Serieo that cropa out in the Carlabad potaah area.

The main upoourea of the formation are near Lake Avalon, north of

Carlabad; N. Hex. Here the Salado overliea the Tamil1 formation and underlies the Puatler Formation, but the atratigrapbic relatioru cannot be determined positively fro^ examination of the outcrop.

The Salado appeara to overlie the Tanaill Formation conformably and to grade upward into the Ruatler Formation. The lower part of the

Salado gradea laterally aouthmrd into the upper part of the Caatile

Formation. The gradational contact between the Salado and the Castile rises in stratigraphic position from north to south and is the anhydrite and polyhalite have been altered to gypsw. The depicted schematically on the geologic structure sections (fig. 4A). alteration of the evaporFre rocks extends to depths ranging froo

East of the outcrop, the Salado Formation underlies the central 260 feet to almost 1,600 feet below the surface and 16 responsible

part of the potash area at depths of 250-700 feet. In general, the for a fourfold to sixfold reduction in the thickness of that part of

depth to the Salado increases with distance from the outcrop, and the Salado and for a change in canposit ion from dominantly rock salt

it is as much as 1,600 feet at the northeast corner of the area and in the subsurface to dominantly gypsum in the outcrop. The contact about 1,000 feet at the southeast corner. between the two highly dissimilar parts of the formation, known

The Salado Formation is characterized by thick persistent units locally as the "base of leached zone" and also as the "top of salt,"

of rock salt alterlutillg with thinner units of anhydrite and 1s highly irregular, with many closed depressions and isolated

polyhalite (fig. 7). Thin seams of claystone underlie virtrully pinnacles (fig. 8). The contact dips generally eastward but risea Ln

a11 the anhydrite and polyhalite units, and there are a few thin stratigraphic position from the base of the Salado near the west

beds of sandstone and siltstme at long intervals. All the anhydrite side of the potash area to the top of the formation near the

units and beds of clastic rocks are distinctive mecllbers that serve Eddy-Lea County line at the east side of the area. The altitude of I as stratigraphic m~rkerbeds; tvo are formally named rock units. the contact ranges from a high of slightly more than 3,200 feet near

The widespread Cwden Anhydrite nember, named for the North Cwden the northwest corner of the area to a low of slightly less than

oilfield in Ector County. Tex. (Ciesey and Pulk, 1941), lies 1,500 feet at the aouth edge of the area.

90-200 feet above the Castile Formation. The Vaca Triste Sandstone The maximum thickness of the Salado Formation in the potash

of Adams (1944) near the middle of the Galdo Formation is a area is slightly more than 2,000 feet in a northwestrard-trending

quartz- and clay-rich unit of fragmental rocks contrasting sharply zone that parallels the margin of the Delaware basin at the Eddy-Lea

with adjacent beds of crystalline evaporite rocks. County line (fig. 9). The thickness of the Salado decreases slowly

In exposures of the Salado Formation along the vest side of the southward within the basin, but diminishes rather rapidly northward

Carlsbad potash area, a11 the salt has been removed by solution and and westwird from the zone of maximum thichess. The northward

deposits are restricted to a feu small groups of mineralized salt

beds or ore tones vhich are scattered at irregular but fairly short reduction is part of a broad pattern of regiorul change in thickness intervals through parts of the HcNutt zone (fig. 10). at or near the south edge of the northvest shelf area, whereas the Nearly a11 the deposits in the HcNutt zone are mineralogically complex and westward reduction is related largely, if not entirely, to evaporite 1 contain a host of hydrous minerals that are thermally reactive at solution and removal by meteoric vaters. Within the shelf area, fairly lov to moderate temperatures (table 2). local reductions in thickness are sharp over pre-Salado knolls

or "highs" at the Getty, Barber, Halfway, and other small oilfields Rustler Formation vhich appear as douml features on the structure ~ropof routheastern The Rustler Formation, named by Richardson (1904), is the New Mexico published by Stipp and Haigler (1956). youngest salt-bearing unit in the Ochoan Series. The formation is a The Salado Formation is divided into three informal units: mainly exposed in inliers scattered irregularly through the central

lwer salt member, a potash-rich member, knwn locally as the and western part8 of the Carlabad potash area. It is overlain by The three McNutt potash zone, and an upper salt member (fig. 7). the Dewey Lake Pedbeds. The contact between the tvo formations is members are conformable, are laterally persistent rock \urits, and obscured in outcrops by slumping and warping due to evaporite

are about equally rich in rock salt, anhydrite, polyhalite, magnesite, hydration, solution, and removal by meteoric vaters. Prom subsurface and clastic rocks. In fact, they are generally similar in virtually studies, bovever, it appears that the format ions are unconformable

a11 but one respect. The lover and upper members are almost entirely at places near the western edge of the Dewey Lake Redbeds. The free of sylvite and other potassium and most magnesium evaporite discordance and hiatus are not great and they disappear eastvard.

minerals over much of the Carlsbad potash area, vhereas the McNutt Over broad sections of the area the Rustler and the Dewey Lake appear

tone is generally rich in these minerals over much of the area and to be conformable.

contains several extenrive sylvite-bearing potash deposits of economic In the subsurface belov the 'zone of ground-vater penetration,

importance. These deposits are the obvious lithologic feature tbt the Rustler Formation is mostly anhydrite and rock salt (fig. 11). sets the McNutt potash zone apart from the lwer and upper members The ofthe Salado and makes it a fairly natural stratigraphic unit. Table 2.--Evacaritt minerals in svlvite and oolvb11cre de~ositsin the Carlstad pottsh area (nodified fra Bern. 1970) F, melt*; 8, bolling; Lkc, decoaposltion; lkh, dehydration; T, transition]

Therm8l ef fectr and temperature (*C) Mineral Formula W B Dec Deh T

nlner.1 Formula The-1 effect. .ad temperature (.C) - W B Dec Deh T Pictomerite------%(so41 2 *682O 76 0 125 1m - 580 180* Polyhalite------K2-p~(SO414 '21120 880 - - 310-320 - Sylvite------El 770 - - - - Thmardite------Ha SO 2 4 884 - - - 240 Vanth~ffitc------Nr~Mg(SO~)~ wC 800 - 5 15 - - * Mineral hu more than one phase. I Some polyhalite ie ccmnonly present near the middle of the formation, 1 and thin to thick unite of sandstone, siltstone, and ehale are I interbedded at long to short interval.. Dolomite is present in the lower and upper parts of the formation and forme distinct stratigraphic

marker beds which bve wide and persietent development in the potash

are) and other eectiona of southeastern New Mexico. The dolomite

in the lwer part of the formation ia known aa the Culebra Dolomite

Member and tbt in the upper part aa the Magenta Dolomite Member (Adam, 1944, p. 16 14) .

The Ruatler Formation reacher a maximum thickness of about

500 feet in the eaatern part of the potash area. The formation thins

toward the outcrop in the central part of the area (fig. 12). Here

the formation generally ranger in thickneea from about 200 feet to

400 feet, but ite thicknere varier considerably over ahort diatancea.

The variable thickneee ir due in great part to the leaching of aalt

and the hydration of anhydrite by meteoric water.. In general, the

remwal of aalt account8 for a aurked reduction in the thickneaa of

the formation, and the hydration of anhydrite reaulta in an increaae

of thickness (fig. 11).

Dewey Lake Redbeda

The Dewey L~keRedbede, wed by Page and Adma (1940). ia the

youngeat unit in the Ochoan Seriea, but unlike a11 other member. of

the Ochoan it ia entirely free of rock ealt and other evaporite rock.. GROUND-WATER HYDROLOCY Three -in hydrologic unite control the ground-water hydrology

=he D~~~~ mke con~iataentirely of riltrtone and fine-lrained of the Carlrbad potarh mining area. There are: (1) the Pecor River, Uindafone, and generally ran@# in thicbees fr~.ab't 400 feet which raceiver tk ground-water outflow from the project area; (2) the It is exposed in lw bluffs in the cent-1 and to 5s water-bearing etrata overlying the Salad0 Forumtion; and (3) the un~onf~rd~~with of the potash are! (fig. 6) and capitan Limertom and other water-bearing rtrata underlying tb

Salado Fotution. The dirtribution and development of large rolution

featurer, particularly in the Warh D rw and Clayton Barin arear, exert a mJor effect on the occurrence and maremnt of tho pound

water.

Pecor Ri~r . The Pecor River receiver marly a11 the natural dirchrge of

ground water tht mov.8 through the rock8 of the potarh dning sroa.

?hd principal placer of uktural ground-water inflow are at Carlrbad,

vbare water derived fror tho Capitan Limrtoar dirchrger to the

river or to the alluvium bordering the river, and mar Nlaga Bend

(fig. l), where highly darralized water is diecharged frm the Rustler

Porntion to the rivor. Between Carlrbad and Ualaga Bend tb river receiver water frm the alluvium, except in areas where pumping har

l-red tho water tabla below river level.

Hator-bearinn unit. ovorl~in~Salad0 Formtion

A 8-11 mount of ground water occurr in a11 the geologic

formtione overlying the Salad0 Formation, but the main aquiferr or

53 vater-yielding units are the Culebra Dolwite Mmber and basal

.#. --.-..m .PVIr- -- -, rolution breccia zone of the Rustler Formation, the Santa Rose Sandatone, -.-." and the alluvium. Locally, the Gatuno Formation yields vater to uells.

In the area wet of and near the Pecos River, uater fra the alluvism

ir utilized extensively for irrigation purposes. East of tht river,

in the potash mining area, only a few vellr have encountered potable uater. The yields of the uellr are generally low and moat are used

for the waterin8 of livertock. The Culebra Dolomite Member occutr

tbrwghout uch of the area and ir the main rource of vater tapped by

rtock walls. The basal solution breccia zone of the Rurtler Porution,

often referred to ar the "brine aquihr," is the unit that ir wst

rignificant in the rolution of the halite in the upper part of the

Salado Powtion. Table 3 summri~rthe hydrology of the geologic

fo~tionroverlying the Salado Patrotion.

Tbrt fomationr abm the Salado Pomtion reem to be connected

hydrologically and can be cowidered as constituting a ringle multiple-

aquifer ryrtem (figs. 4A, 8). Bow perfectly tbir aquifer ryrtem ic

developed ir an open question and cannot be determined fra tb

existing hydrologic inforution, although the level. of water rtanding

in wllr are rufficiently uniform tht potentiormtric and uater-table

contourr can be conrtructed throughout the area (fig. 8). This water

table and potentiamtric surfaco ranger frcm lesr than 200 feet to

about 1,400 feet above the contact betueon tho gypriferour reridue and

melt-bearing rock in the Salad0 Pdrmotion (fig. 13).

54 ...... _._, *(., --a ...... -... _.."...... _._ v1.-.,._

55 -- .-

Am--.- Am--.- Solution activity and associated collapse, subsidence, and fractur-

ing have increased the overall permtability of the rocka and enhnced

the interforutionnl mwement of water in th aquifer myatem. The

aolution action in the area of the potaah miner alao baa detrirntally

affected the chemical quality of th ground water. Alulyrea of we11

water indicate that the ground water in the mining area contain. uch higbr .rounta of diraolved aubmtancea chn doem tb water of the

surrounding region of New Mexico; thia diatributio~lrehtiotubip 11

indic~tedbat by -th total ,dir.olvad rolidr (fig. 14) and chlorido (fig. 15).

Ground water in tb formtion~above tho Salado Porution ~ea pnorally mouthward and aout,!woatward acroar tb potaah rial- area toward the Peeoa River (Pig. 8). Mort of tb diachrgo of tbgrd water taker phce in the reach of tb Pecor River mar Wlaga 8.d.

Thia diachrp ia from about 850 aquaro miler of tb mining area north of Rojact Gnca, mite and from at leaat an additional 400 aquare milea lying to the nortbeart of tb doing area. Although the total amount of grqund water diachrging to tho hcom River ia not known,

Tbi. end other8 (19b2, p. 69) eatluted that 200 gallom per minute entered the river from the baaal solution breccia tom.

Th potentiometric and water-tab30 contoura outlim a rariea of ground-water ridgea or hisha and trough. or lour (fig. 8), which are bpoud on th regional southrapd to mouthveatward pattern of ground- water awalent. A large aouthreatward-plunging ground-wtar trough extenda from Wlrlaga Bend northeaetvard roughly chrough Nash Drav to

the vicinity of Lmguna Plat.. Another much entaller trough is eaet-

eouthaaat of the Project Gnome aite and extend8 from the routheamtern

part of T. 24 S., R. 30 B. e?at-northeartvard acroaa T. 24 S., R. 31 E.,

to T. 23 S., R. 32 E. A aouthvard-plunging trough ie in tha area of

Clayton Baain. Water move. ewtheartward tward tha center of thi8

trough from the northuoatern part of tha mining area, aouthuard fra

the northern border region of the mining area, and awthueatward and

wrtvard from a turrw ground-water ridga between Clayton Baain and

Lap# Plata. South of Clayton Baain tbo trough i8 not a well-defined

\ hydrologic feature. #rch of the water in tha trough doer not move

directly tward tbo Pecor River fra the Clayton Baain area. Ilrntaad,

tbo water la diverted routb-awtheartvard through the rocka underly-

ing Qucrbda Ridge into tb ground-water trwgb in the Naah Draw area

(aee Caturn Formation, table 3), where it join* water wing aoutb-

uertvard tward th. Pecor River.

Salado Formation

The S8lad0 Formtion haa an intergranular poroaity end permability

tht ranger fra lw to virtuilly nono (Stevana and othara, 1970,

table 1); Locally, fracture8 and aolution openinga impart a apotty

formtional permability. In the potaah mining area, tb Salado

Forution ir dry except for null pockata of vater or water and gae 1 tbt have been encountered occasionally during mining and tart-drillily Strata underlying Salado Formation operatioar ad for water present in the leached zone developed at the top of the forution. Smof tb. water and gar pocket. are confined Tho Permian to Cambrian redi-ntary rock. underlying tho Salado Formtion coatain water of brim comporition and are under high under high prerrure. In much of the mining area ground water moving - arterian prerrure. through tb bra1 part of the Ruotlor Forrtion hr forvd a leached There rake are not axpored in the potuh mining In placr8, the area, but they lie deeply buried in tha aubrurface throughout uch of zom along the top of tho Salado Forvtion (fig. 4A). routhoartern Mu mxico and ueatorn Teur. leachad row extendr more thn 200 feet into tha Salad0 For~tion. UcNeal (1965, figr. 1-7) rhwd tht in t& potarh mining area tha elevation of the poten- lbrt of tb dirrobed rolidr in tho brim in tb baral rolution zone I tiortric rurfacee of differoat zo~r(excluding the Capitan Li~rtone) of tb Burtler Formation hr been obtailud frm tho leacbd zoru. of tbre rock8 ranger fraa feu feet to a feu hundred feet above or G. 0. Wcba (written c-., 1972) ortfutar tht during th klw tb land rurface. part 5 million pars... "ralt br ken dirrolved laterally in the At Project Gnm rite where tha average elevation of th. land 8urface ir about 3,400 feet, the potentimtric vicinity of Carlabad, New tbxico, at an average rate of about 3 112 surfacer are at elevatiom betmea 3,400 and 3,800 feet, which ir to 4 miles per dllion yearr... This conclurion 18 bared on tb fact 600-1,000 feet above tb tqof tb halite in tha Salado Forution. that the dirtaaca from tb eartern front of the Gw&lupa Uountaiar 1 t& direction of tho &lop of tha potentioP.tric rurfacer differr to th. prerant uortera lidt of ujor ralt kdr ir abmt 18 to 20 I *-what, but it ir gonorally to the .art or aortbart in routhoartern dler and on the follwiag arrunptionr: (I) tho Og.1lala Forvtion Nau mxico. fomnrly extended acrorr th Pecor River valley at leaat ar far ar the The Capitan Limrtone and arrociated dolmitic part of tha Yater front of the Gwdalupe Uountain8, (2) tha Pecm River valley in the and Tanrill ForutioM form tb topmort aquifer in the rtrata bonath vicinity of Carlabad br been fomd eince Ogallak ti-, and (3) the the Salado Formation. Og.lla1a lorution h.8 been eroded and the Permian malt dirrolved frm There forutiom crop wt or lie at rh.11~1

thir area during tb part 5 million yearn. It doe8 not reem probable deprhr rwthuert of Carlabad, but they are deeply buried eart of the

that ralt extended much fartbr wrt than tha front of th. Gwdalupo city mar the potarh rimr (fig. 4A). The Cmpitan Ltmrtorw ccuprirer

Uamtainr beforo Ogallala time; if tb ralt wr lea. exteoeive before a giant reef 1-2 mile* wid* thot extendr nortbeartuard and eartward frw Carlabad acrore tho mining area; the Yater and hnrif 1 Forutionr adjoin Ogallala rim thir ertirte is coruorvative."

*thodo of prospecting and exploration ohafto frawhich mnin entries are driven into the ore bodieo. pa-1s All prompecting and exploration in the diotrict ha8 been done by of ro- and pillaro are developed off the mnin entries. hole. drilled fra the ourface. Moot of the holeo ware drilled into Th -in entries are 8enerally 15-20 feet wide and 8 feet high. tm top of tha Salado by mea~of churn or rotary drilling rig. The Where double antrieo are driven, they are opacad 50-55 feet apart. The braakthrougho are about 7 feat high, 32-34 feat wide, and are holeo were completed through the ore soma with a diamond drill. Cooing driven on 100- to 150-foot centera. wao oat in the upper part of tb hole and cemented into tb top of the The average roaP aizeo are 34 x 42 feet. malt. The caring and cement ma1 prevented water frm the Ruatler and The bight of tb row, detemimd by tb thickmoa of the ore bed8 baing mined, ranger fror 4-10 feat. younger rock. frm entering the hob. After the hole8 #re c-leted Each ore body ia developed to ito econmic limit8 by the above and r.rpled, the caoing war pulled and the holeo plugged with cement method. Thir cycle of mining la referred to a0 t'firat miningmtand frm bottm to top. In 0- of the earlier drilling the lolr parto of reoulto in an ore recovery of about 50-55 percent. the holes wre plugg8d witb mud, but thooe parto above tb top of the oalt #re filled witb c.Prnt. It can b aooumod that all exploration Second mining ot fi-1 mining 10 the removol of pillaro and the retreating from the wter edger of the developed area tauard the uin hole0 drilled for potaoh hve hen effectively oealed. The daneity and diotribution of the exploration and developmat hulageuaya and ahfto. Ybaa thio mining cycle io capletad, tb total

drilling are rhwn on figure 17. In gerral, the pattern and denrity ore recovery approacbeo 85-90 percent. I of drilling reflects the pooition or the econmic limit8 of the pota8h Piml mining reoultr in th raoval of pillar rupport and the i 1 deposits. Outoide tha dewely drilled .nu the ore horizono in the eventual eubridence of the mined areao. Reentry into tho caved oreoo 1 Salado are capooed of halite and only minor awunto of 10 not pooaibla.

-Shaft. Minine -thodo Twenty-five ohafts haw been ounk at the oiteo of tb 1'1 mines in

The bedded potaoh depbsito are nearly flat lying aver large area.; the diatrict (fig. 4). The ohaft location. and other partinnt data

therefore, modified coal-mining methodo have been uoed in extracting are ahwn in tabular form on table 4. None of the ohafta ha been

tha ore. he ore-bearing horizom are reached through vertical .bandonod or decariorioned. marly all ohafto are concrete or .teal

end "Tenth" LOMI. Nati0~1Potarh Co.'r Lea mi- and the Kerr-&Gee It Pa reported that the rhaftr, with the porrible exception of, Cbmicel Corp. rim heve produced from tha "Tenth" ore ZOM. Teledyne Potarh Co. No. 1 and No. 2, are in excellent condition. The approxiute rtratigraphic poritionr of the ore zoner are rhovn in

Extent of mine uorkinnr figure 10. Forty year. of large-tonnage mining in the relatively thin-bedded Stabilitv of mine workinnr ore deporitr in the dirtrict her rerulted in an exteorive uze of under- fhe entrier, roam, and pillar. developed during the "firrt ground workingr. Tb rim workingr in tb dirtrict cover an area in cycle" doing are derigmd to inrure rtability CameMUrAte with rafr excerr of 45 rquera dler. Ru average bight of tb worki~raway fratho vicinitier of tho rbftr and tb uin entries ir about 7 faet. and efficient mining practice. Back failure uy occur where tb back ir only a few incbe to l foot blou A clay reu. 'fh. floor. and hckr are generally flat or gently r1op.d bcaure tb Jn- Tha urnupportad ralt bed8 bve a tendency to pull away fron the clay bed becaure of the ing rthodr and tb rim layoutr are derignrd to follar tb nearly flat loore bond batween tha two rock type.. regional dip of tb bed.. B~ckfallr are controlled by tha judiciour and extenrive ure of bolting. Fb. mined area. are irregular in rbp. but rcut ere elongate in

a north-nortbart direction. Thim configuretioa reflect# tb variation Cavinn and rubridence of tb potarh content of tha ore bdr and not tb contilruity of tha en- During final mining moat of the pillar rupport 14 removed and the In other word., there are chamical variationr, or closing malt bedr. - worked-out areas gradually rubride or cave.. nore then 50 percent of cbmical fecier within a ringle bed, and are not veriationr in tb tho mined area8 are now caved (fig. 16). In thoae mirum whare mining regiwul redimtntation. Iur been capttad, the rubrideace ir nearly 100 percent of the

Orm br been mlmd fra four bedr or zone8 in tb Salado lorution. mined bight.

Tb mort extenrive workingr are in tha loutrt or "Pirrt" ore zone, which In moat caved area. tho rubridence 1. reflected in the overlying Niw miner in ir between 650 end 800 feet belw tha top of tha Salado. rurface by the development of gentle deprerrionr. Fracturing at tb Teladyoa Potash Co. No. 1 the district h.v. produced ore frm thin zone. rurface in tb rubridence arean cannot be accurately upped or deter- Intermtiom1 h~rproduced from the "Firrt" and "Fourth" ore zone@. mined beceure of tb cover .of uncotuoli&ted rurficial uterialr. S- Mmralr and Chamice1 Corp. br produced frm tb loPirrt,o@"Fourth," fracturing her been noticed in the paved highuayr tbt crorr the rub- and "Fiftha' zorur. Duval'r W.rh Draw mi- br produced from tb "Pirrt" aided area..

69 runk by the U. S. Ataic Energy Comir.ion ar a part of tb Plwahare Although detailed rtudier of the aubaidence area8 have not been program. Only a brief ru~~~ryof the ~eology ad dercription of thc mde, raw apculationa concerning the ~chanimminvolved can be made. mined area. ir given in thir report. Detail4 can be obtaimd frm

Subrurface obrervationr of the rubriding area8 LndicLe that tN rock. reportr on Project Cnog (U. S. Geol. Survey, 1962).

u CO~O~~VO above the mi-d area8 Me0la.l~ d-d a ai~le block The Cnw rluft uar runk to a depth of 1,202 feet. The ahft after final mining ia completed. Etacturin& uywall occur in tN La circular in plan, bar an inair diuter of 10 feet, and ia lined rubelding block, particularly in tN dolo~iteLdr above tN SaWo, vith reinforced concrete to a depth of 722 feet. It penetrated about but the pattern ir not known. N uniqw phyrical prmrtier of tbe 200 feet of aurficial and Pleirtoce~deporitr a11d 1,000 &st of ult prohibitr tN develo~ntof open fracture.. The fracture. Peniu rock.. Tb top of tb ra1t ir about 650 feet belw the collar 1 fo-d am tigbt or quickly sealed by flowage or recryrtalli~tion of th rhaft. Ttm bottm of the rhaft ir in ralt about 550 feet balm i of tbe mlt. %a 8b8ence of water mepa* into th drr in tb area. tb top of tb Saluto Formtion. Rock. eqored in tho abaft are rhwn of rubaiL1ncr 10 indicative of the aelf-reaHng character of tb aalt on table 5. The #hot chhr ir con~ctedto the ahaft by tuo parallel beds. driftr eacb approxi~tely1,100 feet long. The drift. and chamber are Nther evidence for the cohe8iverrr of tU rubridere block i4 near tb bare of tb upper third of the ralt aection. About 1,000 feet tUt mining ir currently Uing carried on in two dm. in ore Uda of uaaive aalt ir ertiuted to be prerent belw the botta of th

;bout- - 50 and 100 foot ab*. the bott~of tU caved block. or lower rluft and drift. inlevel. The ore bed8 being mimd have ruffemd no noticeabb Tb Cnor rluft var abandoned and realad by the AEC in Novhbar rtructural deformatilm other than the 8.8 end elevation cUnger due to 1968. The decairrioning of the rbft war done under the rurveillance the rubridence. of Repoldm Electrical W Engiqering Co. and ir reported on by Tappan No &ta are a~ailableon tU effect that 8ubridewe h.8 Ud and Lorenr (1969). A11 uteriair giving a contact radiation dore rate the movemnt of water in tN aquifer. above tU saldo. of wre than 0.1 milliroentgenr per hour wre rewved fra the rurface

Gnom rhaft an6 workinnr and placed in tb~rhaft br flurhed ar a brim rlurry dwn a drill hole

h Gnc~rite and ahaft are mar the center 01 roc. 34, that interrected OM of the driftr. . 23 S., R. 30 . Eddy ty,N. x.fig 16 TN rUft Tb rhaft contailu contadluted mtal rcrap, OM drrp truck, four Tablo 5.--Rockr ornored in tho Cnor rhaft . , .,-* min carr, a hoirt un-caga, mQvariour othr ntrrialr, iaeludi~~ga I I I M~tbbolow(Thickmr~ Lithology krfaco (foot) (faot) conridorable amount of cont.riautod roil and ralt ruck. Tho report doer Bolocaw 0-43 43.0 1 Uncoorolidatod ' not rtatr hw far up tb Obft tb contuilutod ntorialr oxtond. hporito 1 rand I I I Uncon- tamtautad roil war placrd in tho uppor part of tho rhaft to within 5 feat (irtuau Tonvtion Friable iand- atom and of tb rurfaco, ada prrumnt plug war formd by f illing tb lart conglwrato 5 faat uith concroto. Douy Lake Podkdr Thin-baddod Podan 1 91.2 ( 202.1 I riltrtom I In addition, a11 tort drill holer wro pluggod with comnt to tho top of tho 8.18do.

Chiaf ly Boc.uro of tb conditioan that pow oxirt at tb rhft, tb'Cnor wprum and anhydrito bo I rhaft or drift8 probably cannot rafoly and~oconaicrllyrohbilita- Mgonta Doldta Silty dolaito .... do...... 361.3-382.2 wdr I I I tad. .do. 382.3-495.5 tautirk wmbrr Chiofly ...... solution ntninu activitior anhydrito and gypam Fb KM8.r City Torting Laboratory wr tb firrt of mo capanlor do...... Culabra Doldtc .... to conduct otp.tLrnta1 rolution mining projactr in tho car1rb.d .roo. m.kr ihir rxporLrnta1 projoct involvod rttomptr to oatablirh a coluwction chiofly clay ....do...... and rilt uith ktuon two baroh0108 about 200 feat apart in tho YY 1/4 aoc. 22, rou morrr and aohydrit. T. 20 S., 1. 29 1. Tb project war rtartod during tb lato 1940'8 and onbd during tb 1950'8. 651.2-709.3 Upper loacbd Chiof ly clay- ....do...... During tb dd-1960'8 Conti~ntalOil Co. conductrd an oxpor- udmr atom and riltrtom Lrntal aolution mining projoct in tb Culrbad arm (mvir and Shock, Chiofly impure- do...... 709.3-1,202 492.7 Unloacbd Salad0 .... 1970). tonrtion halito rock Tour tort holor uro drilled in th 8Y 1/4 roc. 12, T. 19 8., I with rou ~nhydrito, P. 30 K., about 3 1/2 dl08 mart of tb Southwart Potarh Co. rbft. polyhalit., and i riltatoo. Tb drilling pattern was in the shap of an equilateral triangle Lma County, with more than 60 percent of the total oil and gar 8ale8 The with a fourth hole in the center, 200 feet frm the apex wells. in the State, rank8 firrt among a11 counties in the United Stater in wells were drilled to a depth of 1,150 feet and were co~pletedin the the value of hydrocarbon production. The producing wlla are concentrated "Third1' ore zone of tb Salado Formation. Subrurface connection8 betwan in an arcrute belt tht in general reflecta tha porition of the buried I well8 wra ertablirhed by hydraulic fracturing frm tb center or in- reef tht mark8 tha tranrition zone between tha Delaware barin and the 1 jection well. northvart rblf area and tha central barin platform. i During the life of the experirnt an elliptical cavity 280 feet Th mrt productive oil and gar zone8 are in the Permian rock8

long and about 80 feet wide at it8 bradeat part and 5-10 feet deep lying hlw tho Cartila Formation. Hwever, 8- production ha8 crm Tb rbpe war formed. About 175,000 cubic feet of ralt8 were removed. frm upper, riddle, and louar Paleosoic rtrata in tha eartern, wrtern,

adrise of the cavity war determined by a ronar rurvey. and nortbartern part of the area. TIm producing soma for the oil and

Ttm well8 were cared and cemanted into tb top of the Salado to gar pool8 in Eddy and &a Countier are rhovn in table 6. Pre- prevent water frm tho mar-rurface aquifer entering the hob.. Production in tha vicinity of Carlrbad ir mortly frm rock8 of

rurbly there hole8 were plugged with cemant when tha project v.8 Grublupian age, particularly tb Grayburg and San Andrea Forutiolu, completed. frm tb rock8 of bonardian and Wolfcwian age, and frm rock8 of Penaoylvanian age. Tha dirtribution of well8 and developed oil and OIL Atm GAS PRaoucT.IoN gar fieldr a8 of 1964 are rhaun on figures 18 and 19. In general, the Oil war firrt produced in Eddy County, N. Ibx., frm tha farour wllr near tb wart mrgin of the Delaware barin are 8,000-10,000 feet Arteria pool which war dircovered in $924. Since tbt tir tbre br deep, mat of thcue in the vicinity of th potarh miner are frm 1,500 hen a rteady increare in tha production of oil and gar in routh- to 3,000 feet deep, and many well# are more thn 3,000 feet deep. In eartern H.w mxico. Tha oil and gar fieldr in Eddy and haCountier - - tha more central and eartern part of the barin, tha deptb of tb well. are the .oat productive in New Ibxico. A8 of 1966, the fieldr in mnerally are 4,000-14,000 feet. Tha deepest well in the mlavare barin, Eddy County hd produced almort 197,000,000 bbls (barrelr) of oil and drilled 21,275 feet to barersnt, encountered large rererver of gar con- 112,000,000 )(CP (thourand cubic feet) of gar. Tb production frm Is. denrate in reveral sonor and probably ir tho firrt of uny wildcat8 that County war about 1,700,000,000 bblr of oil and 2,6W,000,000 llCF of B.8. vill be drilled in tha relatively unexplored deeper part8 of the barin.

Southeartern New Hexico im now a well-ertablirhed oil- ad SEUmED REFERENCES gar-producing area. The pmral geology is well knwn, but umxplored A&-, J. E., 1944, Upper Pamian Ochoa Serier of Delaware barin, Wert large area. rtill ramin. Th. rearch for rtratigraphic trapr and Teur and routheartern New Mexico: Am. Arroc. Petroleum Geologirts favorable rtructurer in tha deeper part. of the Delauare barin undoubted- Bull., v. 28, no. 11, p. 1596-1625. ly vill rerult in tho dircovety of now fieldr. Tha area vill probably -1965, Stratigraphic-tectonic &velopment of Delaware barin: Am. I contimv to b. one of tha moat actively explored &rear in tha mtion Arroe. Petroleum Coologirtr Bull., v. 49, no. 11, p. 2140-2148. I bcaure of tb high ruccerr ratio. &tar, R. L., 1942, Tha oil and gar reoourcem of New Mxico ~zdmdA7: 1 bbv mxico School nimr Bull. 18, 320 p. CONCUJS IOUS i Berg, L. C., 1970, Salt mimrolr, & v. 1, h-ntal arpectr, of Tbt part of tho Carlabad potuh area in Tpr. 21, 22, 23, I(.ckeorie, R. C., ad., Differential thermal amlyrir: New York, and 24 S., Ro. 31 and 32 E., br the lawert denoity of drill holeo Acad. Rear, p. 463-475. for potuh, oil, and gar, io farthemt frm tb dirrolution front in I Bjorklund, L. J., and Wttr, W. S., 1959, Geology and water rerourcer tb ralt rection,.br a rubrtantial thicknorm of coarolidated cover of tha Carlrbad area, Eddy County, New Mexico: U. S. Cool. Survey abwe tb ralt rection, and contailu tho mximm thickmrr of Salad0 open-file report, 322 p. Forition ralt at rearomble depthr belaw tho rurface. Sou of tb Breta, J. U., and Uorbrg, C. L., 1949, Tho Opllala Formation y.rt of mimd-out potarh miner ryprwide ureful rtorage. th Llano ~rtacadoLG. ~xJ: JOU~. ~eo~ogy,v. 57, no. 5, p. 477-490.

Cooper, J. B., 1962, Tart holer drilled in support of ground-water

iwertigationr, Project Cn-, Eddy County, New mxico--baric

&ta report: U. 8. Cool. Survey TEI-786, 116 p. -1962, Ground-vator invartigationr of tho Project Cnm area, Eddy and ba Countier, New Mexico: U. S. Ceol. Survey TEI-802, 67 p., 17 figr. Galley, J. E., 1958, Oil and geology in the Permian Basin of Teus Cooper, J. B., and Glanzman, V. M., 1971, Ceohydrology of Project Gnome L. C., site, Eddy Cwnty, New Plexico: U. S. Gaol. Survey Prof. Paper 712-A, and New Wxico, in Weeks, ad., Habitat of oil-La aympo8iue:

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