Crosssection across the Jornada del Muerto, Engle, and northernPalomas Basins, south-central New byRichard P. Lozinsky, New Mexico Bureau of Minesand Mineral Resources, Socono, NM 97801

Introduction eastward into the Cawizozo-Capitan area (Kelley, 1971).No McRae strata were penetrated in this well. The absenceof the McRae Formation in this part of the Jornada del Muerto brings up two important questions:1) doesthis absence suggest a pinch out of the McRae west of the well and, therefore, the easternlimit of McRaedeposition? or 2) does the absenceindicate an erosional truncation with the McRae originally extending farther east? These are difficult questions to answer because the regional extentof the McRaeis poorly understood.To date, McRaeouicrops have only been recognized in the Cutter sagf[ornada del Muerto area. Kelley and Thompson (1,964)speculated that the McRae dep- ositional area extended into the Carrizozo-Capitan area based on correlation of the McRae Formation with the Cub Mountain For- mation. Similar lithologies and general stratigraphic position were the basis for correlation. However, it is very difficult to document if the McRae and Cub Mountain Formations were co-extensivebe- causeof limited outcrops and no subsurfacedata. More detailed sedimentologic studies of these units are necessaryto answer these questions. The Sierra"K" StateNo. L well also penetratedPermian Glorieta and Mississippian Lake Valley strata that are absent in the Cutter sag-Caballo and Mud Springs uplifts. Unit thicknesses shown on the western side of the Jornadadel Muerto and in the Cutter sag are based on measured sections in the Caballo-Cutter sag uplift by Kelley and Silver (1952),Bushnell (1953),and Mason (1976).

Cutter sag Del Muerto Basin Jornada The Cutter sag, a structually low part of the Caballo-Fra Cristobal uplift, divides the Jornada del Muerto from the Engle Basin. Units in this area generallydip befween 10-15'eastward. McRaeForma- tion thicknessin the Cutter sag is problematic.Bushnell (1953)es- timated the McRae to be about 1,000 m thick, but this estimate is based on extrapolation acrossElephant Butte Reservoir where faults and other structuresmay be present.Based on mapping by Lozinsky (1986),McRae thickness is probably closer to 500 m. This is the thicknessused in the crosssection. Data from the Sierra "K" StateNo. L well indicate that eastward Faulting is more common in the Cutter sag than in the from Jornada the ftrlter sag all Paleozoicunits, except the San Andres For_ del Muerto. Faults in the Cutter sag usually have stratigraphic sep- mation, thicken, and Upper Cretaceousuniis thin. Erosionaltrun- arationsof 100m or less.The Hot Springsfault marks the boundaiy cation is.probably the cause of the Cretaceousthinning as opposed between the Cutter sag and the Engle Basin. At the surface, the Hot to a sedimentarypinch out becausethese Cretaceous-rocks^eitend

t t o r<-s o a S o d ct)

O 5mi # O 5km

FIGURE l-Location of map of cross section and study area. Numbers in blue refer to wells listed in Table 1. Hatchured line indicates railroad.

New Mexico Geology August 7987 SierroCuchillo Ronge PolomosBosin EngleBos o

c) c, = c, (I) o C I o I E E CIN c E ard o o uz mW t4E o -e o) 2,500 (9 @ tlL 2,OOO vI r,500 r,ooo 500 o Tv? - 500 K-P? -r,ooo -t,500 p€ 2 pe 2

FIGURE 2-Cross section acrossthe fornada del Muerto, Engle, and northern PalomasBasins. Refer to Fig. 3 for explanation of unit llmbols' Plio- Pleistocenebasalt flows that partly cap the Cutter sag u." .r6t shown. Surface geology compiled from LoZinsky (1986),Heyl et al' (1983),Maxwell and Oakman (1985),and Machette (written comm. 1982).

\ much as 700m or more thick. Note how the Upper Cretaceousunits 9e PolomosBosin EngleBosin I Jornododel Muerto thin westward in the Engle Basin. This thinning is probably due to pre-SantaFe erosion. The McRae Formation has also thinned to "ol o :fi: F.' SontoFe Grouo ibout 27 m in the Gartland 1 Brister well. No McRae strata were T :@' .El recognizedin either the West Elephant Butte FederalNo. 2 or the e I Sumhit 1A Mims wells. MesaverdeGroup strataunderlie the basin I Volconics B F \\\\\\\\\ fill in the two wells. However, the two wells probably do not indicate oI Inl rusives r E accuratelythe thickness of the McRaeFormation east of the Gartland Y McRoeFormofion }Z 1 Brister well becausethey are located about 4 km south of the cross a \\\\ sectionline. Thus, McRaestrata probably disappearjust west of the I e MesoverdeGroup Gartland L Brister well and south towards the Summit 1A Mims l. MoncosShole well. The McRae disappearance may be the result of pre-Santa Fe DokoloSondsfone erosionor it could representthe McRae'swestern limit of deposition P 50n Anores lormolron r ul- becauseMcRae units are not found farther west (Jahns et al., 1978; e \ \\ \ \ \ \\ \ \ \ \\ \\t Glnriafaac I al., 1983). m (L Heyl et YesoFormotion AII wells in the Engle Basin penetrate dioritic(?) intrusives of var- o AboFormotion in the YesoFormation. These intrusives have in- n Bursum-HuecoFormolion o_ ious thicknesses the thicknessof the Yeso,especially in the Gartland 1 Brister (L creased ''n g MogdolenoGroup well. A fault is hypothesized between the Gartland 1 Brister and for the elevation differ- r/t: KelleyLimestone West Elephant Butte No. 2 wells to account LokeVol ley Fm LokeVolley Fm. enceto the top of the Precambrian. JA PerchoShole PerchoShole Oiole Formolion OnoteFm (?) Mud Springs uplift Srl :usselmon Dolomifr The western portion of the Engle Basin probably representsa Monloyo otd Group buried part of the Mud Springs uplift becausethe basin depth de- El PosoGrouo creasesand the northeasternextension of the Mud Springs uplift Com Bliss Formolion projectsinto this areaof the crosssection (M. Machette,pers. comm. ry€C (' uplift is a northeast-tilted (' Gronitic B metomorohicrocks teSZ;.for the most part, the Mud Springs d block. However, where exposed near T or C, the Mud Springs uplift FIGURE3-Stratigraphic chart for crosssection. Unit symbolsrefer to those is complex structurally and contains an overturned syncline (Kelley shownin Fig.2. and Silver, 1952).These same complexitiesmay also occur in the buried part of the cross section. The West Elephant Butte Federal No. 1 well shows that the Upper Cretaceousunits are absenton this buried block and that the basin fill rests directly on limestone of the Springsfault dips about 70-80' to the west and has at least7,220 m San Andres Formation. Pre-SantaFe Group erosion probably re- of down-to-the-westseparation (Lozinsky, 1985).The Hot Springs moved the Cretaceousunits and part of the SanAndres Formation fault is shown as a single fault because,in this area, the trace is from the Mud Springs block. submergedbeneath the watersof ElephantButte Reservoir.This fault The tops of units between the Gartland L Brister and West Elephant may actuallybe a complex zone containing many splaysand small Butte Federal No. 1 wells differ greatly, especially the depth of the fault blocks as seen in exposuresnorth and south of the reservoir. Precambrian.Thus, there may be anothermajor fault betweenthese Chapin (1983)has interpreted faults like the Hot Springs as major two wells. The thicker PennsylvanianMagdaiena Group in the West right-lateral strike-slip faults of late Laramide age that have been Elephant Butte FederalNo. 1 well may be due to one of the following reactivatedas normal faults during late Cenozoicrifting. reasons:1.) late Paleozoicsyn-depositional faulting; 2) juxtaposition acrossa strike-slipfault; 3) repetition of beds due to faulting; or 4) Engle Basin steeperdips. Between the West Elephant Butte FederalNo. L and The Engle Basin is a half graben with its deeper portion to the Gartland L Garner wells, the Santa Fe Group greatly thickens over east along the Hot Springs fault. Here, the basin fill is probably as a distanceof 3 km. This thicknessincrease over sucha short distance

August 1987 Nau Mexico Geology Cutterso9 Jornododel Muerto Bosin z. o e q, o' = c a O I 2 3 4 5km u, o_ # Y O | 2 3mi c 6P Io) m E (D E :t Elephanl 2,500 o = a Eutte 9 2,OOO -+lReservoirF t,500 I,OOO 500 o -500 - r,ooo - r,500 pe -2,OOO pc -2,500

probably delineatesthe Mud Springsfault, which marks the bound- graphic section as that for the Engle Basin_with the addition of ary between the PalomasBasin and the buried uplift. Sildran, Devonian, and Mississippianstrata (Fig. 3). This samesec- tion may also be presentin the subsurfaceof the PalomasBasin. PalomasBasin The PalomasBasin is an eastward-tilted,half grabensimilar to the Conclusions Engle Basin as evidencedby gravity data (Gilmer et al., 1985)and by eastwarddips of Santa Fe Group beds along the western edge of the basin (Heyl et al., 1983).Basin-fill thickness is probablygreater than 2,000m along the easternside of the PalomasBasin. Here, the Gartland 1 Garner well bottomed in the SantaFe Group at a depth of 1,988m. This well penetrated mostly poorly sorted, coarse-to fine-grained sand with minor silt and clay interbeds. These sedi- ments may be proximal alluvial-fandeposits derived from the Mud fornada del Muerto Basins.Tertiary volcanic units exposedin the Springsuplift. SierraCuchillo Range probably extend an unknown distanceeast- Heyl et al. (1983)mapped the surfacegeology along the western ward into the PalomasBasin. Little is known about the subsurface margin of the PalomasBasin, including a basin-boundingfault. They geologyof the PalomasBasin because of limited well control. When showed that the easternflank of the SierraCuchillo Rangeconsists t-hiswork is combinedwith areageophysical studies (such as Gilmer of Tertiaryvolcanic units. Due to a lack of well control in the Palomas et al., 1986),a more refined interpretation of the subsurfacegeology Basin,it is not known how far east these volcanicsextend into the may be possible. PalomasBasin. However, thev do not extend as far as the West AcxNowr-rpcMENrs-Ron Broadheadaided in interpreting geo- ElephantButte FederalNo. 1 well becauseno volcanicunits are seen physicallogs. This paper benefitedfrom reviews_byR. Harrison, J. in the well cuttings.Thus, the volcanicsmust either pinch out some- Baiker, M. Bowie, f. Hawley, C. Chapin, and W Seager.Lynne where in the PalomasBasin or have been eroded from the Mud McNeil typed Table1. This work was supportedbythe New Mexico Springsblock before deposition of the SantaFe Group. BureauoiMines and Mineral Resources,Frank Kottlowski, Director. It is not known what units are presentbelow the volcanics.In the Monte Brown drafted the figures. SierraCuchillo Range,fahns et al. (1978)reported a similar strati- Continuedon page63

TABLE l-Well data. Well numbers refer to those shown in blue in Fig. 1. Data was derived from analyses of geophysical logs, lithologic logs, and in some places, well cuttings. NP, not penetrated; *, estimated tops or thicknesses; t, total thickness of dioritic(?) intrusives in Yeso Formation.

Surface Total Tops (m) Thickness (m) Well Name; location; Elevation depth no. completion date (m) (m) TKm Ku Psa Py Pa Fm QTsf TKm Ku Psa Py Pa Fm PL

Gartland 1 Garner; 1,500 1,988 >1,988 11-12!5W r2t27t50 West Elephant Butte t,509 2,204 1.,1861.,066 772 415 -401 -645 323 r20 354 297 816 2M Federal No 1; 123+ 7-129-4W; 72112182 Gartland 1 Brister; 1,480 2,617 1,0387,01.1. 581 355 778 -563 NP NP M2 27 430 226 533 38s 47"1* 225* 8-725-4W; 1.l2ll5l - 1.,034* - 1 tqq* 226+ redrilled 9/20/55 '112 West Elephant 1,394 2,303 798 577 346 -183 - 653 -880 595 221. 231. 234 295 471. 226 Butte Federal No. 2; 29+ 3-13S-4W; 1/5/83 Summit 1,{ Mims; 1,393 1,888 789 354 125 -1.1.0 -367 NP NP 604 415 ))q 235 257 477* 226* 2-725-4w; 1.013151. - 838' - 7,064* 26+ Sierra "K" State No 1; 1.558 2.396 996 793 333 -& -777 NP <20? 542 203 460 397 707* 225* 35-125-7W; 8ll0l70 -7,026*

NewMexico Geology Aogust 1.987 Exploration activity in New Mexico re- portion of the Ortiz mine grant, Santa Fe structure38 mi northwest of SantaFe. This County, concentrating efforts in the Lukas hole, secondof three planned, was designed and CaracheCanyon areas.Long Lac planned to gather scientific data on geothermal sys- to complete12 holes during the year. tems as well as to learn more about formation St. Cloud Mining Company pursued an of ore deposits.Molybdenite (MoS.), along on-going sampling and evaluation program with small amounts of copper,lead, and zinc, in the Chloride mining district of the Black was encounteredbetween 80 and 400ft, some Range,Sierra County. Essentially, efforts are possiblyof ore grade. geared toward the production of precious- The New Mexico Bureau of Mines and metal-bearing siliceous smelter flux. Ship- Mineral Resources(NMBMMR), along with ments have been made from the U.S. Treas- funding from the New Mexico Energy Re- primarily becauseof an ever-tightening web ury mine, Great Republic mine, and other searchand Development Institute and pri- of environmental red tape. properties. Sunshine Mining Company re- vate industry completedthe secondyear of - A possiblegold find id being evaluatedby linquished its option on the St. Cloud-U.S. a projected 4-yearprogram to evaluate strip- lylolycorp, Inc. (division of Unocal, Corp.) in Treasury mine in mid-year after a small, and pable coal resourcesin the San TuanBasin. the Red River areain northern New Mexico. apparently unsuccessful,drilling and sam- A total of 56 holes was completed during The nearby Questaarea has been mined for pling program. 1986:35 in the Menefee Formation around Also in the Chloride mining district, First San Mateo, La Ventana, and Chacra Mesa; MississippiCorp. completedassessment 10 in the Menefee/Crevasse Canyon For- drilling on the Hoosier and Silver monument mations in the Gallup coal field; eight in the properties, while the area around the Weber CrevasseCanyon Formation near Crown- shaft (extreme north end of the district) was point and Borrego Pass; and three in the Fruitland Formation near Star Lake. Junebugcampground. But the areais within NMBMMR staff also provided geologic ex- a-wildernessstudy area,and both permit ap- pertise and chemicalanalyses as part of an plicationshave been denied. exploration drilling program on the yttrium Similarly, LaPaz Mining Co. attempted to rare-earth deposits at Laughlin Peak in Col- develop a small gold placer on Beaf Creek fax County. near Piflos Altos, Grant Countv but became A few properties other than those men- embroiled with the Army Corp of Engineers tioned above are currently being promoted over a section 404 permit (which regulates vigorously on the basis of very high gold the placing of fill material back into i river and/or platinum values. Someof these(par- or stream). The permit was denied on the ticularly the platinum "deposits") will even- basisthat the mining activity by La Pazwould tually be exposed as fraud. The would-be critically damage downstream water and investor is advised to exerciseextreme cau- habitats. An unexpected molybdenum find was re- tion. Long Lac Minerals Exploration continued vealed in an exploration hole drilled by Los -Robert W. Eaeleth to drill on its gold prospect in the southern Alamos National Labs in the Valles caldera NMBMMRMining Engineer

Continued page57 from guide to selectedcauldrons and mining districts of the References Datil-Mogollonvolcanic field, New Melico: New Mex- ico Geological Society, Special Publication no.7, pp. 131-138. Kelley, V. C., 1955, Regional tectonics of south-central New Mexico: New Mexico Geological Society, Guide- book to 5th Field Conference, pp. 96-fiL Kelley, V. C., 7971,,Geology of the Pecoscountry, south- easternNew Mexico: New Mexico Bureau of Mines and Mineral Resources,Memoir 24,75 pp. faulting in the southem Rocky Mountains with em- Kelley,V C., andSilver,C.,7952, Geologyof theCaballo phasis on petroleum exploration; in Lowell, J. D. (ed.), Mountains wjth special reference to regional stratig- Rocky Mountarn foreland basins and uplifts: Rockv raphy and structure and to mineral resources,including Mountain Association of Geologists, Denver, pp. 1691 oil and gas: University of New Mexico, Publications in 779. Geology,no. 4,286 pp Clemons, R E., King, W. R., Mack, G. H , and Zidek, J Kelley, V C., and Thompson, T B, 1964,Tectonics and (eds.), 1986,Truth or Consequencesregion: New Mex- generalgeology of the Ruidoso-Carrizozo region, cen- ico Geologica.lSociety, Guidebook to 37th Field Con- tral New Mexico: New Mexico Geological Society, ference,317 pp Guidebook to 15th Field Conference, 110-121.. Gilmer, A. L , Mauldin, R A., and Keller, G. R., 198d,A Kottlowski, F. E., Flower, R. H., Thompson, M L., and and cross sections of the Cuchillo quadrangle, Sierra gravity study of the Jornada del Muerto and Palomas Foster,R. W., 1956, Srratigraphicstudies o{ the San !9unty, New Mexico: U.S. Geological Survey, Open- Basins:New Mexico Geological Society,Guidebook to Andres Mountains, New Mexico: New Mexico Bureau fiJeReport 86279, scale7:24,000. 37th Field Conference, pp. 131-134. of Mines and Mineral Resources,Memoir 1, 132 pp. Seager,W. R., 1986, Third-day road log, from Truth or Heyl, A. V, Maxwell, C. H , and Davies, L L , 1983, Lozinsky, R. P, 1986,Geology and late Cenozoic history Consequencesto southeastem and Geology and mineral deposits of the priest Tank quad- of the Elephant Butte area,Sierra County, New Mexico: San Dego Mountain via I-25 and the Jomada del Muerto: rangle,Siena County, New Mexico: U.S. Geological New Mexico Bureau of Mines and Mineral Resources, New Mexico Geological Society, Guidebook to 37th Field Swey, Miscellaneous Field Shidies Map MF1555, scale Circular 187, 40 pp Conference, pp. 35-52 7:24,000. Mason, f. T., 1975,The geology of the Caballo Peakquad- Seager,W. R., and Morgan, P., 1979, rift in R H, McMillan,D K, Jahns, O'Brient,J.D, andFisher, rangle, Siena County, New Mexico: Unpublished M.S. southern New Mexico, west ,and northern Chi- D. L., 7978,Geologic section in the Siena Cuchillo and thesis, University of New Mexico, Albuquerque, 131 huahua; ln Rieker, R. E (ed ), Rio Grande rift-tecton- flanking areas, Siena and Socono Counties, New Mex- PP ics and magmatism: American Geophysical Union, ico; iz Chapin, C E., and Elston, W. E (eds.),Field Maxwell, C H , and Oakman, M. R., 1986,Geologic map Washington,D.C., pp. 87-106. n

New Mexico Geology Augtst 1987