analyses of these and other stalagmites for ele- tional reconstructions over the “collapse,” iden- mental variations. Ultimately this study will tification of the last paleo-water table (base of Abstracts constrain specific relationships between physi- porosity), and circular seismic anomalies (possi- cal, mineralogical, elemental and possibly iso- bly representing deepest preserved cave devel- topic variations in speleothems and changes in opment) deeper within the platform suggest effective precipitation. several periods of exposure in which the El Abra New Mexico Geological Society reef was sub-aerially exposed to altitudes of sev- spring meeting eral thousand feet. The Santa Agueda field 3-D seismic survey and interpretation was the first The New Mexico Geological Society annu- TIMING OF CLIMATE CHANGE IN THE acquisition and mapping along the western al spring meeting was held on April 11, SOUTHWESTERN UNITED STATES edge of the Faja de Oro atoll. Special thanks to 2003, at New Mexico Institute of Mining AROUND THE YOUNGER DRYAS, by Vic- PEMEX Exploration-Alfredo Guzman for per- and Technology, Socorro. Following are the tor J. Polyak, [email protected], Jessica B. T. Ras- mission to present this work. abstracts from all sessions given at that mussen, and Yemane Asmerom, Department of meeting. Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131 ROLE OF EVAPORITE KARST IN REGION- Session 1—Caves and karst p. 41 Speleothem growth in moisture-limited regions, AL GROUND WATER CIRCULATION IN Session 2—Paleontology p. 43 such as the Guadalupe Mountains, New Mexi- THE LOWER PECOS VALLEY, by Lewis A. Session 3—Sedimentology/stratigraphy p. 45 co, is a good indicator of past regimes of effec- Land, New Mexico Bureau of Geology and Mineral Resources CEMRC, 1400 University Session 4—Hydrogeology p. 46 tive precipitation. Although the Holocene is seen as a dry period in the southwestern United Dr., Carlsbad, NM 88220 Session 5—Volcanology/structure/geophysics p. 46 States, periods of stalagmite growth are helping Natural ground water discharge occurs from a Poster sessions, morning to resolve the wetter episodes from the drier series of cenotes, or sinkhole lakes, along the Sedimentology and stratigraphy p. 47 ones. The Pleistocene–Holocene transition, an east side of the Pecos River floodplain at Bot- Structure and tectonics p. 50 important and interesting period in the south- tomless Lakes State Park, Chaves County, New Hydrogeology p. 51 western United States, coincides with the Mexico. The lakes are fed by submarine spring Younger Dryas event, best-documented early discharge from the underlying San Andres arte- Soils and CO2 p. 51 human colonization, and extinction of some sian aquifer, which has caused subsurface disso- Poster sessions, afternoon important megafauna. Six columnar stalagmites lution and collapse of overlying gypsum and Paleontology p. 51 from three caves in the Guadalupe Mountains mudstones of the Artesia Group. The lakes are Archaeology p. 55 show growth beginning near the start of the unique in that they occur in a semi-desert set- Caves and karst p. 55 Younger Dryas and ending abruptly in the earli- ting, where annual evaporation rates exceed est Holocene. This period of growth reflects mean annual precipitation by a factor of seven Author and subject indices p. 56 overall wetter conditions for the southwestern or more. An increase in spring discharge at Lea United States from about 12,500 years ago to no Lake in recent years reflects the combined SESSION 1—CAVES AND KARST later than 10,500 years ago. Lack of, or less sta- effects of rising water levels in the artesian lagmite growth from about 14,000 to 12,500 aquifer and enhanced spring flow because of CLIMATE VARIABILITY DURING THE years ago indicates somewhat drier conditions mass wasting processes along the steep eastern LATE HOLOCENE IN THE SOUTHWEST during this interval. Growth hiatuses show the margin of the lake. Although the Bottomless UNITED STATES FROM HIGH-RESOLU- onset of distinctly drier conditions around Lakes cenotes formed before European settle- TION SPELEOTHEM DATA, by Jessica B. T. 11,000 years ago with no growth represented ment in New Mexico, catastrophic solution col- Rasmussen, [email protected], Victor J. Polyak, after 10,500 years ago. The climate remained sig- lapse and sinkhole formation remain active and Yemane Asmerom, Department of Earth nificantly drier until the late Holocene. The peri- processes along this portion of the lower Pecos. and Planetary Sciences, University of New od of most significant growth started during Mexico, Albuquerque, NM 87131 and extended a millennium beyond the Younger Dryas event. We conclude that, although overall The effort to constrain past climate change wetter conditions prevailed during the Pleis- HIGH-RESOLUTION DIGITAL TOPO- depends on the availability of high-resolution tocene–Holocene transition, there is a lack of GRAPHIC MODELS OF SPELEOTHEMS records. This is especially true in continents, synchroneity between the Younger Dryas event OBTAINED FROM A 3-D LASER SCAN- where datable material is scarce. Annual growth and effective precipitation in the southwestern NING SURVEY, by Seiichi Nagihara, banding has been shown to occur in some United States. [email protected], Department of Geo- speleothems; this, combined with U-Th ages sciences, Texas Tech University, Lubbock, TX that have an uncertainty of around 25 yrs (2- 79409 sigma) in clean Holocene samples, suggests that speleothems have the potential to provide A detailed three-dimensional topographic map THE CAVES OF FAJA DE ORO, by Dan M. Cox, robust, quantitative climate data. In moisture- of the interior of a natural cavern, if available, 1402 Hidden Terrace Dr., Sugar Land TX 77479 limited regions, such as the southwestern U.S., would be very useful in understanding its geo- stalagmite growth and growth hiatuses, annual Seismic interpretation of the Santa Agueda field morphic development. However, obtaining band thickness, and mineralogical, elemental, 3-D survey reveals a complex history of repeat- such a map is extremely difficult and time-con- and isotopic variations in speleothems can be ed exposures of the Lower Cretaceous El Abra suming, if one simply relies on conventional used as a record of regional effective moisture. reef front, along the western edge of the Faja de surveying techniques. Here we test the feasibili- From stalagmite growth in the Guadalupe Oro atoll. The highest primary porosity is found ty of using a 3-D laser scanner to quickly gener- Mountains of New Mexico, this region is shown within the back-reef debris apron. This deposi- ate high-resolution topographic models of the to have experienced greater than present-day tional facies tract subsequently controlled per- interior of a cavern. A 3-D laser scanner is a type moisture beginning ~4 ka, specifically between meability pathways that lead to cavernous sec- of land-based LIDAR (LIght Detection And ~3 ka and 0.8 ka, following a dry middle ondary porosity development. Repeated sub- Ranging) instrument. It sweeps the surrounding Holocene. From the annual band thickness of aerial exposure resulted in this cave system environment with optical rays. The rays pro- multiple stalagmites, an indicator for growth reaching late stage maturity with the “collapse” duce reflections when they encounter solid rate, this region experienced distinct wet and of the largest caverns. Within this readily map- objects. The instrument records the angle of each dry events over this time period; for instance pable “collapse” zone all remnants of cavernous ray and measures the two-way travel time of the wet events (intervals of increased growth rate) porosity are filled with cave breccias, syn- and corresponding reflection. The survey data can are observed at 2.8 and 2.0 ka, and a dry event post-exposure Tertiary clastics. Along the east- be displayed on a computer screen as a cloud of (hiatus) between 0.7 and 0.45 ka. A wet interval ern edge of the “collapse,” there are preserved reflection points that delineate the geometrical is also observed between 0.46 and 0.17 ka, corre- lesser caverns as the original higher porosity shape of the scanned objects. Individual reflec- lating to the Little Ice Age. Calibration of the and permeability facies that controlled subse- tion points can be spaced within 1 cm from one speleothem record to the historical climate quent cave development pinched out into the another. Here we report data from a 3-D scan- record is currently in progress, along with mud-rich lagoonal facies. Structural and deposi- ning survey conducted in the Big Room of the

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 41 Carlsbad Cavern. Almost 8 million reflection those of hydrothermal pyrite (-23‰), consistent induced sinkholes, caves), lowering of the points were recorded in the vicinity of a flow- with cave formation during ore deposition. The ground water (locally resulting in subsidence), stone feature called “Frozen Niagara Falls” dur- aqueous sulfate that formed jarosite and some of contamination of ground water (i.e. waste water ing an overnight experiment. Later, we con- the primary gypsum was likely derived from discharge, acid mine drainage), and changing structed a continuous, 3-D surface model of the the oxidation of isotopically light H2S. Some of ground-water flow patterns (including increased flowstone by interpolating the point cloud. the later cave-fill gypsum at Hansonburg has mine water drainage). However, the effects of high δ34S values (6.5 to 13.9‰) indicating aque- mining in karst in New Mexico are poorly docu- ous sulfate derivation from the overlying Permi- mented. Future production of these resources an formations. can be accomplished with no significant impacts SULFUR REDOX REACTIONS: HYDROCAR- The cave at the Copiapo deposit in the North to the environment, if done carefully with a com- BONS, NATIVE SULFUR, MISSISSIPPI Franklin district is unmineralized and is located plete understanding of the geology. VALLEY-TYPE DEPOSITS, AND SULFU- below the level of ore, a feature commonly RIC ACID KARST, DELAWARE BASIN, observed in the Illinois–Kentucky fluorspar dis- NEW MEXICO AND TEXAS, by Carol A. Hill, trict. The presence of prosopite, CaAl2(F,OH)8, Department of Earth and Planetary Sciences, and fluorite in the halloysite envelope around METER SCALE CALCITE SPELEOTHEMS IN University of New Mexico, Albuquerque, NM the deposit attest to the high F activity in the THE MISSION TUNNEL, SANTA BAR- 87131 earliest mineralizing solutions. Exceptionally BARA, CALIFORNIA: A 90-YR RECORD 34 Sulfuric acid karst should be considered as an low δ S values for some of the jarosite (~-25‰) OF GROWTH IN FRACTURED ARKOSIC integral part of the evolution of petroleum- and gypsum (-11‰) also indicate that aqueous SANDSTONE, by J. R. Boles, boles@magic evaporite basins. In the Delaware Basin, New sulfate formed from isotopically light H2S, as it .ucsb.edu, University of California, Santa Bar- Mexico and Texas, sulfuric acid karst is related did at Hansonburg and Carlsbad. However, the bara, Department of Geological Sciences, to hydrocarbons, native sulfur, and Mississippi occurrence of the cave below the level of jarosite Santa Barbara, CA 93106 Valley-type ore deposits through a series of sul- formation suggests that the fluids from depth The 6-km-long Mission Tunnel was completed fur redox reactions: were already acidic before H2S was oxidized at in 1912 to provide water from Gibraltar Dam to higher levels and implies cave formation by Santa Barbara, California. The subhorizontal, hydrofluoric acid speleogenesis. partially unlined tunnel cuts through steeply dipping marine sandstone and shale of the Santa Ynez Mountains, to a depth of 670 m beneath the ground surface. Ground water seep- MINERAL DEPOSITS, MINING, AND ing from the unlined sandstone sections has pro- KARST, by Virginia T. McLemore, ginger@ duced extensive and spectacular calcite gis.nmt.edu, New Mexico Bureau of Geology speleothems on the roof and sides of the tunnel, Stage 1 in the above redox-reaction diagram and Mineral Resources, New Mexico Institute including large stalactites, cave bacon, flow- represents the microbial (Desulfo-x) production of Mining and Technology, Socorro, NM 87801 stone (1.5 m), thick rinds on wood beams and of isotopically light H2S from hydrocarbons in Karst terrains contain many types of mineral cables, and rare stalagmites. Calcite growth the basin. Stage 2 represents the non-microbial deposits by providing ideal deposition cavities rates are up to an order of magnitude higher production of economic native sulfur deposits for minerals. Minerals associated with karst than estimated in natural caves. The extensive in the basin (e.g., Culberson sulfur mine). Stage have been exploited for many years. More than precipitation of calcite records almost 100 yrs of 3 represents H2S that migrated from basin to reef 80 mining districts in New Mexico are in car- evolving fluid flow from fractures and water- to form Mississippi Valley-type ore deposits bonate rocks, and most have some indication of rock interaction. (metal sulfides), located in the same structural karst before, during, or after mineral deposition. The cements in the Mission Tunnel exhibit and stratigraphic traps as the caves. Stages 4 and Many of these deposits could not have formed growth bands with episodes of dissolution and 5 represent the migration of H2S into the Capi- without some karstification. Mineralization and precipitation, resulting in a loosely cemented tan reef complex and the dissolution of cave alteration are strongly controlled by secondary structure. Both manganese oxide and ferric passages by a sulfuric acid mechanism, with porosity such as faults, fractures, brecciation, oxides are associated with some speleothems. gypsum forming as a by-product. Thiobacillus and dissolution features produced as a result of The earliest calcite tends to be more porous than could have been involved in the reactions of karstification. Lead-zinc deposits hosted by car- the latest calcite in the speleothems. these two stages. Stage 6 represents the forma- bonate rocks in New Mexico account for 37% of Based on carbon dating, the source of carbon tion of cave sulfur from H2S in the zone of aera- the lead and 56% of the zinc production from the in the calcite appears to be largely modern (CO2 tion, and Stage 7 represents the oxidation of this state. Mines from the Todilto Limestone in the from soil?). Sr isotopic values suggest that the sulfur to gypsum within the cave environment. Grants district account for 2% of the total urani- calcium is derived from feldspar or clay reac- um production. Uraniferous collapse-breccia tions. Oxygen and carbon isotopic values from pipes in the Cliffside, Doris, and Jackpile– the calcite range from -4.5 to -9 and -4 to -15 Paguate mines have yielded uranium ore as part (PDB), respectively. The oxygen isotopic compo- SULFURIC AND HYDROFLUORIC ACID of mining adjacent sandstone deposits. More sition in the most recent calcite is about 5 per mil SPELEOGENESIS ASSOCIATED WITH than 600 collapse-breccia pipes are found in the higher than expected for isotopic equilibrium FLUORITE-JAROSITE MINERALIZATION Ambrosia and Laguna subdistricts, but only a with the present 26ºC seep water, which is about ALONG THE RIO GRANDE RIFT, NEW few are uranium bearing. The pipes were prob- -7.5 SMOW in the central part of the tunnel. This MEXICO, by Virgil W. Lueth, New Mexico ably formed by solution collapse of underlying disequilibrium suggests that biological process- Bureau of Geology and Mineral Resources, limestone or evaporate. es are involved in the crystallization. Both oxy- New Mexico Institute of Mining & Technolo- Furthermore, the sedimentary rocks subjected gen and carbon isotopes show systematic trends gy, Socorro, NM 87801; and Robert O. Rye, U.S. to karst are potential commodities. New Mexico of heavier values (as great as 5 per mil) with Geological Survey, Denver Federal Center, is known for large reserves of limestone, gyp- growth. This trend and the decreasing porosity Denver, CO 80225 sum, potash, and halite. The Carlsbad potash with growth may result from gradual slowing of Caves associated with fluorite-jarosite mineral- district is the largest potash producing area in the flow because of self sealing of the fracture ization in the Hansonburg and North Franklin the U.S. New Mexico ranked 7th in gypsum pro- pathway, slowing of the water-rock interactions Mountains districts may have formed from dif- duction in the U.S. in 2001. Limestone is quar- during leaching of the mineral surfaces, or the ferent solution types. These caves display ried throughout New Mexico for aggregate, evolution of biological communities. spongiform and irregular walls and contain sig- cement, concrete, crushed stone, dimension nificant amounts of halloysite clay. stone, and specialty uses. More than 70% of The caves at Hansonburg are mineralized and crushed stone produced in the U.S. is from car- CAVE FERROMANGANESE DEPOSITS: large masses of gypsum contain mineralized bonate rocks. Guano (a source of nitrate) also SUBTERRANEAN SOIL DEVELOPMENT?, limestone rafts and textures indicating lime- was mined from caves throughout New Mexico by Michael N. Spilde, [email protected], Insti- stone replacement. The low δ34S values of gyp- in the late 1800s and early 1900s. tute of Meteoritics, University of New Mexico, sum (-7.2‰) and jarosite (-25 ‰) are similar to Geologic hazards related to mining of mineral Albuquerque, NM 87131; Penelope J. Boston, those for gypsum and alunite, respectively, at deposits in karst terrains include removal of rock Department of Earth and Environmental Sci- Carlsbad Caverns, New Mexico and also to that results in subsidence (i.e. formation of ence, New Mexico Institute of Mining and

42 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 Technology, Socorro, NM 87801; and Diana E. (putative manganese-oxidizing bacteria) in the agassizi, lizard, snake, large raptorial bird; the Northup, Department of Biology, University of deposits and the underlying punk rock. Analy- bat Myotis, desert cottontail rabbit Sylvilagus New Mexico, Albuquerque, NM 87131 sis of genetic sequences of DNA extracted from auduboni, the pocket mouse Perognathus, the Accumulations of low density, soil-like material the deposits showed only weak evidence for woodrat Neotoma, extinct pronghorn antelope line the walls, floors, and ceilings of some caves. iron- and manganese-oxidizing bacteria. There- Capromeryx minor, and a large carnivore—possi- In Lechuguilla and Spider Caves in Carlsbad fore, enrichment cultures were designed to tar- bly the short-faced bear Arctodus simus. Previous Caverns National Park, New Mexico, this mate- get these organisms and document their pro- attempts to radiocarbon date the guano and fos- rial is particularly well developed, but similar duction of iron and manganese oxides. DNA sil bat bones from Slaughter Canyon Cave have material has recently been found in Jewel Cave, extracted from these enrichments showed the proven unsuccessful, suggesting these deposits South Dakota. The deposits are diverse in com- presence of known manganese-oxidizing bacte- are older than 40,000 yrs Before Present. position with variable amounts of clay and Al- ria. Geological techniques, such as scanning oxide minerals, and all are rich in Mn- and/or electron microscopy, energy dispersive spec- SESSION 2—PALEONTOLOGY Fe-oxides. The mineralogy and microbiology of troscopy, X-ray diffraction, and bulk chemistry these deposits bear striking resemblance to ter- were used to characterize the mineralogy of the REDISCOVERY OF HERRICK’S “COAL- restrial soils in which iron, aluminum, and man- deposits and to search for evidence of bacterial MEASURE FOREST” IN THE PENNSYL- ganese oxides have accumulated. morphologies at every step of the study. Thus, VANIAN SANDIA FORMATION, SOCOR- 4+ the combination of techniques from the two dis- RO COUNTY, NEW MEXICO Lithiophorite [(Al,Li)Mn O(OH)2], nord- , by Spencer G. ciplines more effectively allowed us to tease strandite and gibbsite [Al(OH)3], goethite, kaoli- Lucas, New Mexico Museum of Natural Histo- nite, and illite have been identified by XRD, and apart the various aspects of the production of ry, 1801 Mountain Rd. NW, Albuquerque, NM abundant nanocrystalline Fe-oxides were found these ferromanganese deposits. 87104; William A. DiMichele and Dan S. Chaney, by TEM examination, similar to minerals found Department of Paleobiology, National Muse- in laterite soils. Likewise, todorokite [(Mn2+,Ca, um of Natural History, Smithsonian Institu- 4+ tion, Washington, D. C. 20560; and John Nel- Na,Mg,K)Mn3 O7•H2O] and birnessite [(Ca, THE EXTINCT FREE-TAILED BAT TADARI- son, Illinois State Geological Survey, 615 E. Na) (Mn4+,Mn3+) O •1.5H O], often observed 0.5 2 4 2 DA CONSTANTINEI AND ASSOCIATED in soil nodules, are also present in these cave Peabody Dr., Champaign, IL 61820 VERTEBRATES FROM PLEISTOCENE deposits. A diverse microbial community has In 1904 Clarence Luther Herrick (1858–1904) DEPOSITS IN SLAUGHTER CANYON been identified in these ferromanganese published an article titled “A coal-measure for- CAVE, CARLSBAD CAVERNS NATIONAL deposits by 16S rDNA sequence analysis, and est near Socorro, New Mexico” in the Journal of PARK, SOUTHEASTERN NEW MEXICO, includes microorganisms whose closest relatives Geology. In it, Herrick described a lycopsid flora by Gary S. Morgan, [email protected] are manganese- and iron-oxidizing bacteria and (including three new species of Lepidodendron) .nm.us, New Mexico Museum of Natural His- nitrogen-fixing bacteria. from “fire clay” of Pennsylvanian age being tory, 1801 Mountain Rd. NW, Albuquerque, The similarities in mineral and microbial mined for brick manufacturing in Socorro. Her- NM 87104 species composition to that in soils suggest that rick’s description of the locality was vague, and these cave deposits undergo a process similar in In April 2002, a field crew consisting of paleon- it has not been revisited in nearly a century. In some ways to terrestrial soil development. Both tologists, cave specialists, and volunteers from 2002 we relocated Herrick’s locality, which is chemical and microbial processes may influence the New Mexico Museum of Natural History east of Socorro near Arroyo de la Presilla in sec. the formation of these cave deposits. Chemical (NMMNH), Carlsbad Caverns National Park, 11 T3S R1E (NMMNH locality 5312). The “fire weathering from the condensation of weak car- and Kartchner Caverns State Park in Arizona, clay” is a refractory dark-gray to black shale in bonic acid in the cave atmosphere may con- conducted excavations of the fossiliferous Pleis- the lower part of the Middle Pennsylvanian tribute to the dissolution of the bedrock carbon- tocene bat guano deposits in Slaughter Canyon (Atokan) Sandia Formation that can be followed ate, but microbial breakdown of bedrock proba- Cave (also known as New Cave) in Carlsbad on strike for more than 2 km, and that is fault bly plays a more significant role. The oxidation Caverns National Park, Eddy County, south- repeated often along this transect. The Sandia of reduced iron and manganese releases H+ ions, eastern New Mexico. We collected 21 bags of Formation section at the lycopsid locality begins and the microorganisms themselves may release sediment (~300 kg) from two test pits in differ- with ~4 m of trough-crossbedded quartzose organic acids, both of which contribute to disso- ent areas of the cave. Test Pit 1 is ~2 m deep by sandstone and quartzite-pebble conglomerate lution of carbonate. The residual weathered 1 m wide; Test Pit 2 is ~1 m deep by 1 m wide. scoured into the underlying Proterozoic granite. products, rich in secondary minerals and organ- The soft, unconsolidated guano deposits are These coarse clastics are sharply overlain by ic matter, are essentially subterranean soils. overlain throughout the cave by a thin (~10–15 ~2.5 m of gray and yellow, fine-grained, massive cm thick) multilayered flowstone deposit. We to thinly laminated sandstone. The lycopsid excavated the sediments from the vertical walls bark is concentrated in the top of this fine sand- of trenches (some up to ~5 m deep) left behind stone interval, which is overlain by the “fire PARTNERING WITH BIOLOGISTS: BETTER by miners who dug the guano for fertilizer. clay” interval, ~ 4 m of gray and black shale, silt- ANSWERS THROUGH COLLABORA- Because most of the fossils consist of tiny bat stone, and fine sandstone, which in the lower TION, by D. E. Northup, Department of Biolo- bones, the sediments were carefully excavated part contains localized lenses of coal, a few Lin- gy, University of New Mexico, Albuquerque, and placed into nylon bags for transport to the gula, and an extensive flora. We suggest this suc- NM 87131 NMMNH for screenwashing and sorting. cession represents a fan-delta (coarsening-up Except for the description of the extinct free- basal clastics) directly overlain by an estuarine Multidisciplinary studies that involve geo- tailed bat Tadarida constantinei, little paleontolog- deposit (lycopsid beds and fire clay). Our collec- chemists, mineralogists, microbiologists, and ical research has been conducted in Slaughter tions of fossil plants from the lycopsid bed molecular biologists can be crucial to our quest Canyon Cave. The vast majority of fossils from include Lepidodendron cf. L. aculeatum, L. cf. L. to investigate the role that microorganisms play this cave, numbering in the thousands of bones, mannabachense and L. cf. L. jaraczewskii, Lepi- in various geological materials and processes. belong to Tadarida constantinei. This species is dostrobus, Synchysidendron, Sphenophyllum, stig- Biologists have developed a suite of techniques very similar to the living Mexican free-tailed bat marian roots and strap-like leaves of the lepido- such as DNA stains that reveal cell shapes in Tadarida brasiliensis but is ~20% larger in most dendrids. The type specimens of the species of rock material, redox dyes that reveal live vs measurements. Other fossil samples of a large Lepidodendron Herrick named were destroyed in dead cells, and molecular phylogenetic tech- Tadarida that may be referable to T. constantinei a fire in 1910, so newly collected lycopsid speci- niques that assist in identifying living organ- are known from Mammoth Cave in Kentucky mens are topotypes of the species. However, isms present in geological materials using genet- and Hamilton Cave in West Virginia, both of Herrick’s species appear to be within the range ic sequences. Functional gene studies also can which are medial Pleistocene (Irvingtonian) in of variability known from single trunk speci- identify whether genes are present to carry out age. T. brasiliensis forms large colonies in caves mens, or to be sufficiently similar to previously particular processes such as manganese oxida- throughout the southwestern U.S., including the described species to be problematic. This lycop- tion. main cave at Carlsbad Caverns. The tremendous sid locality in the Sandia Formation is signifi- Our study of the origin of ferromanganese abundance of T. constantinei fossils in Slaughter cant because it indicates that a typical coal deposits in Lechuguilla and Spider Caves illus- Canyon Cave strongly suggests that this extinct swamp flora existed in New Mexico during trates the effectiveness of multidisciplinary species also formed large colonies. Ten other early tectonism of the Ancestral Rocky Moun- studies. Incubation of deposits with INT (a species are represented in the Slaughter Canyon tain orogeny. redox dye) and counter-staining with acridine Cave vertebrate fauna: desert tortoise Gopherus orange revealed the presence of stalked bacteria

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 43 AMPHISAUROPUS FROM THE LOWER PER- smalli or a separate small taxon. Lucianosaurus South Dakota, North Dakota, Alberta, and MIAN ABO FORMATION, CERROS DE wildi Hunt and Lucas, 1993 is only known from Saskatchewan. T. rex is the most widespread AMADO, SOCORRO COUNTY, CENTRAL one locality in the upper (R2) portion of the for- Mesozoic dinosaur species, and the genus NEW MEXICO, by Allan J. Lerner, Spencer G. mation and is represented by isolated teeth. Tyrannosaurus (= Tarbosaurus) is also one of the Lucas, New Mexico Museum of Natural Histo- Prosauropods are poorly represented in the most widespread as relatively complete and ry, 1801 Mountain Rd. NW, Albuquerque, Bull Canyon Formation. The R1 fauna includes diagnostic remains are present in both Asia and New Mexico 87104; and Sebastian Voigt, only an indeterminate premaxilla and a lower western North America. Geiseltalmuseum, Martin-Luther University, jaw fragment. The R2 fauna includes one dorsal The pattern of tyrannosaur diversity during Domstrasse 5, Halle D-06108 Germany centrum and a number of isolated teeth. the Late Cretaceous resembles that of other Amphisauropus, a tetrapod footprint ichnogenus In conclusion, the lower R1 fauna of the Bull North American non-avian dinosaurs as a that is widely distributed in the Lower Permian Canyon Formation includes R. callenderi, T. whole in that there is a decline in generic diver- of Europe, has previously been recorded in the smalli, a possible third ornithischian, and an sity approaching the end of the Cretaceous. This United States only from Abo Pass in central indeterminate prosauropod, and the upper R2 is due, in part, to a decrease in provinciality as New Mexico. New Mexico Museum of Natural fauna includes L. wildi and an indeterminate faunas in western North America become History locality 5075 in the Cerros de Amado of prosauropod. increasingly more homogeneous. The distribu- central New Mexico contains a second occur- tion of T. rex does not reflect the general biogeo- rence of tracks that are readily assigned to graphic division between north and south Amphisauropus latus Haubold. These tracks are Laramidia as seen in other Late Cretaceous attributed to a seymouriamorph trackmaker. THE ELEPHANT BUTTE TYRANNOSAURUS dinosaurian clades and in this sense T. rex is an They are found in a 5-m thick crossbedded and REX, by Thomas E. Williamson, twilliamson unusual component of the late Maastrichtian ripple-laminated sandstone about 94 m above @nmmnh.state.nm.us, New Mexico Museum fauna. the base of the Wolfcampian Abo Formation, of Natural History, 1801 Mountain Rd. NW, which is near the middle of an approximately Albuquerque, NM 87104; and Thomas D. Carr, 190-m-thick Abo section locally. At present, no [email protected], Royal Ontario Museum, associated ichnotaxa have been recovered from 100 Queen’s Park, Toronto, Ontario, M5S 2C6 SELACHIAN-DOMINATED VERTEBRATE this unit. The Amphisauropus tracks are well pre- Canada FOSSIL ASSEMBLAGE FROM THE LATE served, and occur in a laterally confined area of During the spring of 1984, the New Mexico CRETACEOUS PICTURED CLIFFS SAND- several meters width that represents a levee or Museum of Natural History (NMMNH) collect- STONE, SAN JUAN BASIN, NEW MEXICO, channel margin. There are no extensive tram- ed a portion of a skeleton (NMMNH P-3698) by Sally C. Johnson and Spencer G. Lucas, New pled surfaces at locality 5075, as seen in the from the Hall Lake Member, McRae Formation, Mexico Museum of Natural History, 1801 Amphisauropus occurrence at Abo Pass. exposed near the margin of Elephant Butte Mountain Rd. NW, Albuquerque, NM 87104 In Europe, Amphisauropus tracks are found in Reservoir (NMMNH locality 353) and referred it In the San Juan Basin, the uppermost strata of alluvial plain and lake margin facies of the to Tyrannosaurus rex. The specimen included a the Pictured Cliff Sandstone record the last Lower Permian red beds in Germany, France, left dentary, right prearticular, a partial right traces of the Cretaceous Interior Seaway as it the Czech Republic, Poland, and Italy. In New palatine, several loose teeth, and a hemal arch. retreated across the continent. A vertebrate fos- Mexico Amphisauropus is not found in Wolf- Additional parts of the specimen were reported sil locality in the Pictured Cliffs Sandstone at campian tracksites from the southern or north- to remain at the site. However, the locality was Mesa Portales near Cuba contains many more ern parts of the state, which were formed on a drowned by rising lake levels and had been terrestrial elements than do other marginal coastal plain and in an upland environment, inaccessible for nearly 19 yrs. marine sandstones lower in the Upper Creta- respectively. The distribution of Amphisauropus During September 2002 the NMMNH recov- ceous section. This site is dominated by selachi- in New Mexico thus appears to be restricted to ered additional portions of this specimen fol- ans with 15 species: Squalicorax pristodontus, the central part of the state, which is interpreted lowing a drop in lake level. Disarticulated bones Ischyrhiza mira, Hybodus sp., Synechodus sp., as an inland alluvial floodplain. were found clustered in a conglomerate; these Squatina sp., Pseudohypolophus mcnultyi, Odon- include a partial right splenial, a partial right taspis cheethami, Odontaspis sanguinei, Cretodus angular, a right articular, a right squamosal, a arcuata, Cretolamna appendiculata, Ptychotrygon right postorbital, portions of several isolated triangularis, Ptychotrygon sp. A, Brachaelurus sp., HERBIVOROUS DINOSAUR SPECIMENS teeth, and several additional hemal arches. Cretodus borodini, Cretodus sp. and calcified FROM THE UPPER TRIASSIC (REVUELT- Diagnostic characters of the postorbital and selachian centra. The site also contains teleost IAN) BULL CANYON FORMATION OF palatine are the basis of our referral of the spec- centra of at least two different species as well as EAST-CENTRAL NEW MEXICO AND imen to T. rex. teleost bone fragments and some very large WEST TEXAS, by Adrian P. Hunt, Andrew B. The Elephant Butte T. rex is significant for sev- teeth of Enchodus. There are at least five kinds of Heckert, Spencer G. Lucas, and Kate E. Zeigler, eral reasons: 1) it represents the only specifically reptiles present: turtles, elasmosaurs, alligators, New Mexico Museum of Natural History, diagnostic dinosaur to be collected from the ornithischians, and saurischians. Also, some 1801 Mountain Rd. NW, Albuquerque, NM McRae Formation and supports a late Maas- very tiny mammal teeth are found at this locali- 87104 trichtian age for the Hall Lake Member; 2) it con- ty. The selachian fauna contains some members The Bull Canyon Formation (Upper Triassic: firms previous identification of this specimen as that are age diagnostic, such as Squalicorax Revueltian) of east-central New Mexico and T. rex and verifies the presence of T. rex in the pristodontus. Whereas this fauna compares well west Texas contains the most diverse Late Trias- southern Rocky Mountain region; and 3) it is the with other late Campanian selachian faunas, sic dinosaur fauna in the world. The majority of most complete T. rex from New Mexico and the there is at least one species that is obviously dinosaur specimens represent theropods, but southern United States. The specimen is far missing, the teeth of Ptychodus mortoni. This has several ornithischian and prosauropod speci- more complete than the single maxilla that has some paleoecological implications for the locali- mens are known. been referred to T. rex from the Javelina Forma- ty and suggests that the water during the time of Ornithischian dinosaurs are represented by at tion of Big Bend, Texas. Moreover, the referral of deposition was very shallow. The presence of least three taxa. Revueltosaurus callenderi Hunt, the Big Bend specimen to T. rex has been ques- dinosaur and mammal teeth also suggests that 1989 is known from five localities in the lower tioned though we agree with the original identi- this site was very close to land. (R1) portion of the formation. R. callenderi is the fication. T. rex has also been tentatively identi- most abundant herbivorous dinosaur in the Bull fied in the Naashoibito Member of the Kirtland Canyon Formation, although it is only known Formation based on the presence of isolated A NEW LATE PALEOCENE TILLODONT from isolated teeth. Technosaurus smalli Chatter- teeth, a partial dentary, a phalanx, and a partial MAMMAL FROM THE SAN JUAN BASIN jee, 1984 is a second R1 ornithischian represent- metatarsal IV. OF NEW MEXICO AND THE ORIGIN OF ed by a dentulous dentary from one locality. Recent identification of T. rex from the North TILLODONTS, by Shirley A. Libed, albinque@ New Mexico Museum of Natural History speci- Horn Formation of Utah and the tentative iden- earthlink.net, Department of Earth and Plane- men NMMNH P-17483 is a portion of a proxi- tification of T. rex from the Denver Formation of tary Sciences, University of New Mexico, mal femur with a prominent fourth trochanter. Colorado show that T. rex was widespread in Albuquerque, NM 87131; and Spencer G. This specimen represents a small ornithischian western North America at the end of the Creta- Lucas, New Mexico Museum of Natural Histo- in the R1 portion of the Bull Canyon Formation. ceous. T. rex has also been identified in upper ry, 1801 Mountain Rd. NW, Albuquerque, NM It could represent a juvenile of R. callenderi or T. Maastrichtian deposits of Wyoming, Montana, 87104

44 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 A new taxon, Nacimientotherium silvestrei gen. et posed of basal, fine-grained wackestones over- Cooke’s Range, and the Oscura, northern San sp. nov., is described from the northwestern San lain by skeletal or phylloidal wacke- Andres, Fra Cristobal, and Caballo Mountains Juan Basin, New Mexico. Represented by a sin- stone/packstone or skeletal packstone caps. (= upper member of Bar-B Formation of previ- gle crushed maxillary fragment preserving LP2- These cycle types are interpreted to record <100 ous usage); and (4) Laborcita Member, a thick M2, Nacimientotherium corresponds in size to ky relative sea-level fluctuations. (<330 m) unit dominated by nonmarine red North American Paleocene Deltatherium, but is The two cycle types stack systematically into beds, basement-cobble conglomerates, and algal smaller than the tillodont Esthonyx (late Pale- seven larger-scale (25–50 m) depositional bioherms in the Sacramento Mountains. Sedi- ocene–Eocene). Comparable to several Asian sequences. Type I cycles, which contain basal mentation of the Bursum was strongly influ- alleged tillodonts (e.g. late Paleocene Meiosty- mudstone facies, are found predominantly in enced by synsedimentary tectonic movements lodon), the new genus appears temporally and the lower parts of sequences, whereas, lime- of the Ancestral Rocky Mountain orogeny, morphologically intermediate between the earli- stone-dominated type II cycles (with skeletal resulting in conspicuous lateral variations in est Esthonyx (E. xenicus) and Deltatherium. Simi- packstone to grainstone caps), are dominant in lithofacies and thickness. The widespread Bur- lar to Deltatherium in premolar morphology, the upper parts of sequences. Stratigraphic dis- sum Formation, of Virgilian and early Wolf- Nacimientotherium is advanced in acquisition of tribution of specific meter-scale cycle types campian age, thus represents a significant tec- a distinct P3 lingual cone, further development within sequences suggests that longer-term tonic pulse in the Ancestral Rocky Mountain of the P4 protocone, reduction of the metastylar (0.5–1 my) relative sea-level fluctuations were orogeny. lobe, and augmentation of the hook-shaped superimposed upon the high-frequency oscilla- parastyle in P3-4. The wide, wing-like stylar tions recorded by cycles. shelves of Deltatherium’s primitive triangular molar dentition are superseded in Nacimien- STRATIGRAPHY AND TAPHONOMY OF totherium by subrectangular, anteroposteriorly THE UPPER TRIASSIC SALITRAL FOR- compressed molars. Exhibiting greater pos- THE BURSUM FORMATION—INTEGRAT- MATION, CHINLE GROUP, IN NORTH- terolingual hypocone flare, crown hypsodonty, ED LITHOSTRATIGRAPHY OF THE CENTRAL NEW MEXICO, by K. E. Zeigler, S. and moderately wide, bilobate, stylar shelves, PENNSYLVANIAN–PERMIAN TRANSI- G. Lucas, New Mexico Museum of Natural the new genus approaches in form the cosmo- TION IN NEW MEXICO, by Spencer G. Lucas, History, 1801 Mountain Rd. NW, Albu- politan undisputed tillodont Esthonyx. Resem- New Mexico Museum of Natural History, querque, NM 87104; J. Spielmann, Dartmouth blances among North American and Asian late 1801 Mountain Rd. NW, Albuquerque, NM College, Hanover, NH 03755; and V. Morgan, Paleocene assemblages indicate faunal inter- 87104; and Karl Krainer, Institute for Geology, New Mexico Museum of Natural History, change. However, confirmation of North Amer- University of Innsbruck, Innrain 52, Innsbruck 1801 Mountain Rd. NW, Albuquerque, NM ican Nacimientotherium as a late Paleocene A-6020 Austria 87104 tillodont transitional to Esthonyx confounds The dominant depositional basin across much of In the Chama Basin of north-central New Mexi- generic derivation from the oldest putative New Mexico during the Pennsylvanian–Permi- co, the Upper Triassic Salitral Formation, origi- tillodont, the Asian early Paleocene Lofochaius. an transition was the Orogrande Basin of the nally referred to as the Salitral Shale Tongue, is Lending decisive support to Deltatherium’s southern and central parts of the state. Strata part of the lower Chinle Group, and is generally recent inclusion within Tillodontia, discovery of that encompass that transition have been given described as a blocky bentonitic mudstone with Nacimientotherium resuscitates a North Ameri- several names: Bruton (1944), Bursum (1946), some interbedded sandstones and siltstones. can origination of the order, defies tillodont clas- Aqua Torres (1946), Red Tanks (1946), Laborcita The mudstones are mottled and contain carbon- sification of aforementioned Asian specimens, (1957), and Oso Ridge (1994) formations or ate nodules, indicating paleosol development. and complicates conventional theories of specia- members. In other areas, the transitional strata The Salitral Formation lies conformably above tion, radiation, immigration, and timing during have either been assigned to the Abo Formation the Agua Zarca (= Shinarump) Formation and the Paleocene–Eocene faunal turnover. or to the Madera (Magdalena) Group/Forma- disconformably below the Poleo Formation. tion without a separate name. A single forma- Fossils recovered from the Salitral Formation SESSION 3—SEDIMENTOLOGY/ tion name, Bursum Formation, best describes indicate an Adamanian (late Carnian) age. The STRATIGRAPHY these strata, which constitute a mappable lithos- Salitral may be broken into three discrete litho- tratigraphic unit throughout their outcrop area. stratigraphic units: a lower green mudstone, a CYCLE AND SEQUENCE STRATIGRAPHY The Bursum Formation thus is as much as 330 m thin medial sandstone bench, and an upper red OF THE MIDDLE PENNSYLVANIAN thick and is interbedded siliciclastic red beds mudstone. We propose formal designation of (DESMOINESIAN) GRAY MESA MEMBER and marine limestone and shale. The Bursum is these units as members of the Salitral Forma- OF THE MADERA GROUP, LUCERO distinguished from underlying Madera Group tion. BASIN, NEW MEXICO, by Lea Anne Scott, strata by its substantial content of red-bed shale The majority of the vertebrate fossils recov- [email protected], and Maya B. Elrick, Depart- and mudstone and some beds of limestone-peb- ered from the Salitral Formation during survey ment of Earth and Planetary Sciences, Univer- ble conglomerate and trough-crossbedded sand- work in the summer of 2002 were recovered sity of New Mexico, Albuquerque, NM 87131 stone. Unlike the overlying Abo Formation, the from the bases of slopes in the upper member. The Middle Pennsylvanian (Desmoinesian) Bursum contains beds of marine limestone and The fossils are predominantly fragments of Gray Mesa Member (240 m) of the Madera calcareous shale. Thus, the Bursum represents a metoposaur amphibian skull and girdle ele- Group is well exposed in the Lucero uplift transitional facies between the dominantly shal- ments, together with a few bone fragments that region in central New Mexico along Mesa Sarca. low marine carbonate facies of the underlying could only be referred to Archosauria indet. The Facies present include: 1) terrigenous mud- Madera Group and the continental red-bed bone fragments are abraded and moderately stones, 2) dark, thin-bedded, fine-grained facies of the overlying Abo Formation. In the weathered, and are found mixed with calcrete wackestones, 3) medium- to thick-bedded skele- keel of the Orogrande Basin (southern Oscura nodules that cover the mudstone slopes. The tal wackestones to wackestone/packstones, 4) Mountains–northern San Andres Mountains), calcrete nodules, as well as the vertebrate fossil medium- to thick-bedded phylloidal wacke- the Bursum grades laterally into the upper part material, are weathering out of the base of a stone/packstones, 5) skeletal packstones to of the Panther Seep Formation and the lower very thick calcrete-pebble conglomerate at the grainstones, and 6) rare pebbly sandstones. part of the overlying Hueco Group. base of the overlying Poleo Formation. Howev- These facies represent deposition in deeper sub- Regional and local variation in Bursum litho- er, although the fossils are weathering out of the tidal (facies 1 and 2) to shallower subtidal facies is best expressed by recognizing four basal Poleo Formation, they were most likely waters (facies 3–6). Facies stack into ~60-m-scale members of the formation: (1) Oso Ridge Mem- incorporated into the conglomerate as reworked upward-shallowing cycles. Cycle tops common- ber, a thin (<12 m) unit containing much Salitral clasts and thus were originally deposit- ly display early diagenetic features (irregular reworked local Proterozoic basement in the ed in the upper Salitral Formation. The black calcite infilling vertical and horizontal Zuni Mountains representing a very proximal advanced degree of weathering indicates a cracks, oxidized burrow mottling, and brecciat- facies; (2) Red Tanks Member, a moderately moderate time of subaerial exposure (>3 yrs), ed fabrics) suggestive of subaerial exposure. thick (<100 m) unit dominated by nonmarine whereas the abrasion of the surfaces indicates Two major cycle types are present: Type 1 shale and mudstone present in the Lucero uplift, exposure and transport of the bone fragments. cycles (4–7 m thick) are characterized by basal Sandia, Manzano, and Los Pinos Mountains, mudstones overlain by either skeletal or phyl- and locally in the Joyita Hills; (3) Bruton Mem- loidal wackestone/packstone or skeletal pack- ber, a moderately thick (<85 m), dominantly stone caps. Type II cycles (3–5 m thick) are com- marine lithofacies present in the Joyita Hills,

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 45 LUMINESCENCE AND RADIOISOTOPE DETAILED MODELING OF GROUND bedrock permeability. When R is about one- CHRONOLOGY OF THE LATE QUATER- WATER/SURFACE WATER INTERAC- third or lower, percolation is dominant, and the NARY MESCALERO SANDS, SOUTH- TIONS NEAR SAN ANTONIO, NEW MEX- amount of percolation depends on infiltration EASTERN NEW MEXICO, by Stephen A. Hall, ICO, by Laura J. Wilcox, [email protected], rate. When R is about 1, both bedrock topogra- Red Rock Geological Enterprises, 17 Esquina Department of Earth and Environmental Sci- phy (slope and depression) and soil characteris- Rd., Santa Fe, NM 87508; Ronald J. Goble, ence, New Mexico Institute of Mining and tics affect water partitioning by affecting the Department of Geosciences, University of Technology, Socorro, NM 87801, Nabil Shafike, water pressure distribution at the soil-bedrock Nebraska, Lincoln, NE 68588; and Hewitt W. [email protected], New Mexico Inter- interface. When the soil becomes saturated, the Jeter, Mass Spec Services, P.O. Box 163, state Stream Commission, 121 Tijeras NE, effects of bedrock surface topography and soil Orangeburg, NY 10962 Suite 2000, Albuquerque, NM 87102; and properties become smaller or insignificant. This The Mescalero Sands is a sand sheet of eolian Robert S. Bowman, [email protected], Depart- suggests that water availability with respect to origin that occurs between the Pecos River val- ment of Earth and Environmental Science, bedrock permeability and water pressure at the ley and the caprock escarpment of the Ogallala New Mexico Institute of Mining and Technol- soil-bedrock interface are two critical parame- Formation in southeastern New Mexico. The ogy, Socorro, NM 87801 ters needed to estimate water partitioning on sand sheet formed on the eroded surface of the Under the Rio Grande Compact, New Mexico is hillslopes. Mescalero paleosol, a regional petrocalcic soil obligated to deliver a specified amount of water that may have developed largely during the to satisfy demands in New Mexico and Texas Sangamonian. The sand sheet incorporates two below Elephant Butte Reservoir. This indicates distinct eolian sand units, the older accumulat- that a finite amount of water is available to New CHEMICAL AND MICROBIAL COMPOSI- ing 90–70 ka directly on the eroded Mescalero Mexico north of Elephant Butte Reservoir for TION OF SUBSURFACE-, SURFACE-, AND paleosol and the younger one accumulating habitat preservation and agricultural, industrial, ATMOSPHERIC WATER SAMPLES IN THE 9–5 ka on top of the older sand; their ages are and domestic uses. Previous investigations have SOUTHERN SACRAMENTO MOUN- provided by optically stimulated luminescence. observed significant seepage losses from the Rio TAINS, NEW MEXICO, by Dirk Schulze- The older sand unit is derived from the Ogallala. Grande to the shallow aquifer between Socorro Makuch, Department of Geological Sciences, During the time interval between deposition of and the Bosque del Apache. Small scale model- University of Texas, El Paso, TX 79968 the older and younger eolian units, a noncalcic ing of a 6-mi reach of the river between Brown Several environmental samples near the Sun red argillic soil developed on the older sand; the Arroyo and San Antonio is aimed at determin- Spot Observatory in the southern Sacramento noncalcic character of the paleosol may be in ing the causes for surface water loss and investi- Mountains were analyzed for chemical and response to the mesic climate of the Wisconsi- gating methods for minimizing such losses. microbial content. The samples were obtained nan. Small parabolic and shrub-coppice dunes Simulations will include alternative river chan- within 1 km2 of each other, one from a drinking mark the modern surface of the sand sheet; nel locations, riparian vegetation changes, and well of the observatory, one from a nearby luminescence ages of one coppice dune place it changes in river/aquifer interactions. Layers spring, one from surface soil, and one from fall- wholly within the 20th century, and cesium-137 included in the model extend upward from the en snow that was sampled about 1 cm beneath content indicates that the upper 22 cm of the Santa Fe Group and lie within the lateral extent its icy surface. All samples were analyzed for coppice dune accumulated since 1954. of the floodplain. Grid cell size is 100 by 100 ft. main cations and anions, total phosphorus, total Information collected to help calibrate the organic carbon, total biomass, phospho-lipid SESSION 4—HYDROGEOLOGY model includes: floodplain geologic cross sec- fatty acids (PLFA), and denaturing gradient gel tions; monthly ground water elevations; month- electrophoresis (DGGE). The surface soil sample EVALUATION OF GROUND WATER / SUR- ly surface water elevations in drains, canals, and exhibited the highest amount of nutrients, bio- FACE WATER INTERACTIONS ALONG A the river; surface water flow data; precipitation mass, and species diversity. Surprisingly, the CRITICAL REACH OF THE MIDDLE RIO records; aquifer pump tests; seepage run results; snow sample exhibited the 2nd highest amount GRANDE, NEW MEXICO, by Brad T. Newton, and three water chemistry snapshots in 2002, of biomass with higher values than the spring Laura J. Wilcox, and Robert S. Bowman, Depart- including the stable isotopes 2H and 18O. This and the ground water sample. This was consis- ment of Earth and Environmental Science, model is a telescopic version of a regional model tent with total organic carbon results that New Mexico Institute of Mining and Technol- of the Rio Grande reach from San Acacia to Ele- showed a total organic carbon content of 16 ogy, Socorro, NM 87801 phant Butte Reservoir that is being developed mg/L in the snow sample. For a follow-up The primary goal of this project is to quantify by the New Mexico Interstate Stream Commis- study, precipitation samples were collected and connections between the surface water and shal- sion. analyzed for microbial content. A culturable cell low ground water systems in the Rio Grande abundance of 4,800 cells per mL of water was valley between San Acacia and Elephant Butte counted. Extractable DNA sequences pointed to Reservoir. The surface water system is dominat- soil-associated bacteria primarily, but also to ed by the Rio Grande, the Low Flow Con- WATER PARTITIONING AT THE SOIL- plant pathogens and possibly human veyance Channel (LFCC), and irrigation canals BEDROCK INTERFACE OF HILLSLOPES, pathogens. These results indicate that the and drains. Ground water and surface water by Huade Guan and John L. Wilson, Department atmosphere may be a much more important samples were collected along several transects of Earth and Environmental Science New environment for microbes than traditionally crossing the river and LFCC in February, June, Mexico Institute of Mining and Technology, realized, at least representing an important tran- and October of 2002 and analyzed for major Socorro, NM 87801 sitional habitat for transport purposes. cations and anions and stable isotopes of oxygen Variably saturated, steady state numerical simu- and hydrogen. lations were conducted on 100-m-long concep- SESSION 5—VOLCANOLOGY/ Stable isotope data indicate that water in the tual hillslopes representing conditions typical of STRUCTURE/GEOPHYSICS shallow aquifer and the LFCC is primarily river mountains bounding New Mexico’s Rio Grande water. Most ground water between the river and rift. Water partitions between interflow in the COLLAPSE AND RESURGENCE OF THE the LFCC was characterized by a fairly constant soil layer and percolation across the soil- VALLES CALDERA, JEMEZ MOUNTAINS, water chemistry with TDS values between 380 bedrock interface. The latter eventually leads to NEW MEXICO: FIELD RELATIONSHIPS and 420 mg L-1, very similar to values for the Rio subsurface recharge of adjacent valleys. Simula- AND 40AR/39AR AGES OF MEGABRECCIA Grande, indicating that ground water between tions suggest that water percolation into BLOCKS AND CONSTRAINTS ON THE the river and the LFCC is derived directly from bedrock is significant for bedrock with perme- TIMING OF RESURGENCE, by Erin H. river seepage. The water chemistry for ground ability greater than 10-16 m2. This permeability Phillips, Department of Earth and Environ- water to the west of the LFCC was highly vari- threshold is below frequently reported fractured mental Science, New Mexico Institute of Min- able with TDS values between 370 and 1,240 mg rock permeability. Given a hillslope with ing and Technology, Socorro, NM 87801; Fras- L-1 , which probably reflects the influence of irri- bedrock permeability above this threshold, the er Goff, Los Alamos National Laboratory, Los gation recharge and water/mineral interactions. mechanism of water partitioning at the soil- Alamos, NM 87545; Philip R. Kyle, Department TDS values for the LFCC are slightly higher than bedrock interface dynamically depends on the of Earth and Environmental Science, New those of the river, suggesting that much of the ratio of infiltration rate over saturated bedrock Mexico Institute of Mining and Technology, LFCC water comes from river seepage. Howev- hydraulic conductivity (R). When R is about 3 or Socorro, NM 87801; William C. McIntosh, New er, the interpretation is complicated by several larger, interflow dominates, and the amount of Mexico Bureau of Geology and Mineral diversions that feed water into the LFCC. percolation depends on the magnitude of Resources, New Mexico Institute of Mining

46 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 and Technology, Socorro, NM 87801; Jamie N. eral distances of 50 km. The current structural soil CO2 flux, it is possible to detect the CO2 Gardner, Los Alamos National Laboratory, Los features of the crust coincide with regions of plume associated with a fault and is therefore Alamos, NM 87545 Paleozoic and Mesozoic tectonic activity as well useful in locating faults that may be buried. By Detailed geologic mapping and 40Ar/39Ar dat- as Proterozoic suture zones. This implies that mapping out the location of faults drill targets ing reveal that megabreccia blocks as large as ancient lithospheric structures, possibly as old are more easily identified and can save money 600 x 400 m were emplaced within intracaldera, as the age of lithospheric formation, may deter- when exploring for geothermal fluid reservoirs. upper Bandelier Tuff (UBT) during eruption and mine current regional deformation styles. The Lightning Dock Known Geothermal collapse of the Valles caldera, and suggest that Resource Area is located southwest of Lords- subsequent resurgence probably was complete burg, New Mexico, and has no known surface within, at most, 90 ky of caldera formation at expression. The geothermal waters are used to approximately 1.23 Ma. The distribution and IS THE DEPTH INTERVAL OF THE SOCOR- heat greenhouses used to grow long-stem roses sources of intracaldera megabreccia blocks are RO SEISMOGENIC ZONE CONTROLLED and raise fish fingerlings. There is also interest highly variable. 40Ar/39Ar ages of selected BY A REDUCTION IN ROCK STRENGTH in exploiting the water as a renewable source of megabreccia blocks indicate that they are com- SUGGESTED FROM EXPERIMENTALLY energy for the region. posed of older pre-caldera units that include the DETERMINED ELASTIC MODULI?, by Geothermal waters rise convectively, then 1.6 Ma lower Bandelier Tuff (LBT; clasts yield Marshall Reiter, New Mexico Bureau of Geolo- commonly flow laterally near the surface. The ages of 1.64 ± 0.04 Ma (2σ)), and a dacitic tuff gy and Mineral Resources, New Mexico Insti- plume of thermal water resembles a mushroom dated at 8.08 ± 0.08 Ma. tute of Mining and Technology, Socorro, NM cloud. Faults in the Lightning Dock Known The timing of resurgence is constrained by the 87801 Geothermal Resource Area are covered by hun- eruption of the UBT and emplacement of the The Socorro seismogenic zone is an upper dreds of meters of alluvium, and have been dif- oldest ring fracture dome, Cerro Del Medio; crustal layer containing earthquakes above the ficult to locate by geophysical methods. Even when faults are located, it is difficult to identify 40Ar/39Ar dating places these time constraints at intensely studied Socorro magma body within which ones carry geothermal fluids. More than 1.232 ± 0.018 Ma (UBT) and 1.19 ± 0.03 Ma the Rio Grande rift. The depth of the seismo- 200 soil CO flux measurements at 50–100 m (Cerro Del Medio). The Deer Canyon and genic zone varies; however, microearthquake 2 spacing were made near the main surface heat Redondo Creek Members of the Valles Rhyolite studies show that the thickness is typically anomaly of the Lightning Dock Known Geot- Formation, erupted before and during resur- between 2 km and 3 km. Near the Arroyo del hermal Resource Area to develop and test the gence, respectively, stratigraphically overlie the Coyote swarm site, a reliable heat-flow meas- soil CO technique as a method of geothermal UBT. However, these units are not shown by urement allows reasonable subsurface tempera- 2 exploration. Measurements were made by the 40Ar/39Ar dating to be measurably younger than ture estimates. It has been suggested that the accumulation method using an aluminum box the UBT, suggesting that resurgence com- base of the seismic zone occurs at temperatures with volume of 0.01 m3, which was placed on menced soon after collapse of the Valles caldera of ~300°C where quartz becomes ductile in the ground well away from any vegetation. The and eruption of the UBT. response to tectonic stress. These temperature flux of CO into the box was measured over 10 Abundant clasts of LBT, derived from the estimates, along with an approximation of the 2 confining pressure with depth, allow depth minutes and showed a range from a low value reworking of LBT-bearing megabreccia blocks, -1 -1 are found within caldera fill volcaniclastic equivalent estimates of normalized elastic mod- of 0.01 ppm.s to a maximum of 0.51 ppm.s . deposits. Fieldwork shows that these 1.6 Ma uli from experimental data, which can be used The sites of the highest CO2 flux are believed to clasts are not syneruptive with Deer Canyon to estimate rock strength across the entire seis- mark buried faults trending northeast-south- lavas associated with resurgence, as previously mic depth interval. Although the depth of a seis- west. These faults may carry the geothermal flu- suggested by Phillips et al. (2002, Proc. NM mogenic zone is likely to depend on a number of ids from a source in the southwest to the main Geol. Soc. Spring Meeting). parameters, data for several granitic rocks from heat anomaly. Previous well water analyses two studies are combined to approximate nor- show that the shallow ground waters trending malized Young’s moduli (E/E0) at the top and southwest of the discovery well have anom- bottom of the seismogenic zone (7 and 9 km alous CO2. Soil flux measurements were repeat- SEISMIC STRUCTURE OF THE LITHOS- depth) as ~0.8 and ~0.65. The normalized bulk able over several days time. Future CO2 flux measurements will be used to refine the loca- PHERE FROM THE COLORADO PLA- moduli (K/K0) at the top and bottom of the zone TEAU/RIO GRANDE RIFT/GREAT PLAINS are ~0.45 and ~0.33. Reduction of the elastic tions of these faults SEISMIC TRANSECT (LA RISTRA) EXPER- moduli, and therefore rock strength, begins at IMENT, by David Wilson, [email protected], depths below 3 km to 5 km because of tempera- POSTER SESSIONS, MORNING Richard Aster, and the RISTRA research team, ture dependence. The reduction of elastic mod- SEDIMENTOLOGY AND STRATIGRAPHY Department of Earth and Environmental Sci- uli predicted across the seismic zone at Arroyo ence, New Mexico Institute of Mining and del Coyote suggests a weakened crustal layer IDENTIFICATION AND MAPPING OF EVAP- Technology, Socorro, NM 87801 that is qualitatively consistent with a semi-brit- ORITE MINERAL ENDMEMBERS IN LAKE tle zone of reduced strength predicted from wet LUCERO AND ALKALI FLAT, WHITE We examine the structure of the lithosphere in quartz rheologies. Experimentally derived elas- SANDS, USING LANDSAT 7 ETM+, by H. A. the southwestern United States using the seis- tic moduli values may be used to predict upper Ghrefat, [email protected] , and P. C. Good- mic impulse response of the earth (receiver crustal strength–depth profiles for regions of ell, [email protected], University of functions) calculated from teleseismic arrivals different tectonic and thermal regimes. At Texas, El Paso, TX 79968 recorded in the LA RISTRA experiment. LA RIS- Arroyo del Coyote increasing differential stress TRA was a northwest–southeast trending, 950.7 Evaporite minerals are the main source of sever- with depth may intersect a weakened semi-brit- km linear network of 57 broadband PASSCAL al industrial and agricultural minerals impor- tle zone to create the seismogenic depth interval. seismometers, deployed during 1999–2001 from tant to the U.S. and world economy. Landsat Lake Powell, Utah, to Pecos, Texas. It was ori- ETM+ data covering the White Sands, New ented approximately parallel to the regional Mexico, have been used in this study. Lake Proterozoic continental accretionary gradient, Lucero and Alkali Flat have been chosen as tar- MAPPING FAULTS IN THE LIGHTNING and oblique to the predominantly north–south get sites. The study aims to: 1) determine the DOCK KNOWN GEOTHERMAL AREA, trend of faulting during Ancestral Rocky Moun- number of endmembers that can be detected ANIMAS VALLEY, NEW MEXICO, USING tain and Laramide compression and Cenozoic and mapped, 2) determine the spatial distribu- SOIL CO2 FLUX MEASUREMENTS, by extension and rifting. We estimate crustal thick- tion of fractional abundances of identified end- Kristie McLin, Philip Kyle, and David Norman, ness and Vp/Vs ratios using the travel times of members assuming a linear mixing model, and Department of Earth and Environmental Sci- direct P-to-S converted seismic phases and con- 3) the ultimate objective will be the application ence, New Mexico Institute of Mining and verted phases that have been reflected multiple of this initial study to future hyperspectral stud- Technology, Socorro, NM 87801 times within the crust. ies. The Minimum Noise Fraction (MNF) trans- Crustal thickness reaches a minimum of 35 km When geothermal fluids rise they often boil giv- form and Principal Component Analysis (PCA) in the center of the Rio Grande rift, and ranges ing off their dissolved gases especially carbon were employed to determine a reduced set of between 42 and 50km thick in both the Great dioxide, which is the predominant vapor phase noise-free spectral bands. The Pixel Purity Index Plains and Colorado Plateau. We observe con- in geothermal systems. The CO2 is likely to rise (PPI) and n-D Visualization (nDV) were con- siderable topography at the base of the crust, along the same faults that act as pathways for ducted on the reduced set of spectral bands to with thickness changes as great as 7 km over lat- the rise of the geothermal fluids. By measuring identify spectrally pure endmembers in the

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 47 image. The following endmembers have been Krainer, Institute for Geology, University of electron images and X-ray maps of elements, identified in the Alkali Flat and Lake Lucero: 1) Innsbruck, Innrain 52, Innsbruck A-6020 Aus- ours will be one of only a few studies to employ gypsum, 2) gypsum with sparse vegetation, 3) tria; Spencer G. Lucas, New Mexico Museum of modern analytical techniques to study reduc- bloedite, and 4) clay plus carbonate. Of these Natural History, 1801 Mountain Rd. NW, tion. Fifteen thin sections were made of samples endmembers, only gypsum and bloedite are Albuquerque, NM 87104; and Garner L. Wilde, collected from the Abo type section near Moun- evaporite mineral endmembers. Mineral maps 5 Auburn Court, Midland, TX 79705 tainair, New Mexico, as well as from the Que- of the spatial distribution and relative abun- Upper Paleozoic strata in the southern Cooke’s bradas area east of Socorro, New Mexico. The dance of evaporite minerals were performed 1 samples include a variety of reduction features Range at Fryingpan Canyon (NW ⁄4 sec. 17 T21S using three different algorithms: Spectral Angle R8W) have previously been assigned to the and grain sizes. Reduction features included in Mapper (SAM), Matched Filtering (MF), and Pennsylvanian Magdalena Group and the the samples are reduction spheres, alternating Mixture Tuned Matched Filtering (MTMF). The Lower Permian Abo Formation. Recent re-exam- layers of reduced and non-reduced rock, and results showed that gypsum has high fractional ination of these strata indicates they encompass shrinkage cracks filled with reduced sediment. abundance in North and South Lake Lucero and three lithostratigraphically distinct units: (1) 18 The lithologies of the samples collected vary Alkali Flat, whereas the fractional abundance of m of cherty limestone and shale; (2) 25 m of from mudstones to conglomerates. Preliminary bloedite is low in Alkali Flat, but is higher in interbedded shale, marine limestone, and lime- studies of thin sections show a significant differ- North Lake Lucero. The results of SAM, MF, and stone-cobble conglomerate; and (3) 100 m of red- ence in the hematite content between the white MTMF are validated by collecting field samples bed mudstone, arkosic sandstone, and lime- portions and red portions of the samples. from different locations within the White Sands. stone/siliceous-pebble conglomerate overlain Hematite is present as grain coatings on detrital A good match has been determined between by the Lower Cretaceous Mojado Formation grains in red portions, but is completely absent results of Landsat ETM+ data, the U.S. Geologi- (“Sarten Sandstone”). The base of unit 1 is com- in the white portions. In some instances the cal Survey library, and field and laboratory posed of thin-bedded fossiliferous limestone amount of detrital opaques is equal between red determined spectra. ASTER, ALI, AVIRIS, and containing abundant fusulinaceans, overlain by and white portions. This contradicts observa- Hyperion data are available and are in the cherty limestone composed of gray limestone tions from most previous studies, and it sug- process of being evaluated for mapping evapor- nodules embedded in brownish cherty matrix, gests that the source of iron for the hematite ite mineral endmembers. Mapping of playa and interbedded brownish to reddish, cherty grain coatings in red portions of the Abo Forma- evaporite minerals is of potential importance for shale. Near its base, unit 1 yields the Desmoine- tion is not from the dissolution of iron-bearing the goal of saline soil characterization, regional sian (DS 1 or 2, Strawn) fusulinaceans Beedeina opaques. Porosity and grain size are both ground water hydrology and quality mineral ex. gr. euryteines (Thompson) and Wedekindellina greater in the white layers compared to adjacent resource development, and climate change. ex. gr. euthysepta (Henbest). Unit 1 is thus best red layers, yet in reduction spheres porosity and assigned to the Madera Group as a Desmoine- grain size are unchanged across the boundaries sian correlative of the Nakaye and Gray Mesa of the reduction sphere. Formations to the north and northeast. Unit 2 MODERN SAND DUNE MIGRATION does not yield age diagnostic fossils but is RATES OF LOS MEDAÑOS IN SOUTH- interbedded shallow marine limestones (thin EASTERN NEW MEXICO, by Christopher nodular limestone beds rich in crinoidal debris STRATIGRAPHY AND CORRELATION OF Mahoney, New Mexico State University, Las in the lower part, fossiliferous nodular lime- THE UPPER CRETACEOUS TOHATCHI Cruces, NM 88003 stone in the middle and upper part), limestone- FORMATION, CHUSKA MOUNTAINS, The small dune field referred to as Los pebble conglomerates, red-bed siliciclastics, and WESTERN NEW MEXICO, by Justin A. Spiel- Medaños, located 25 mi southeast of Carlsbad, reddish mudstones containing abundant pedo- mann, Dartmouth College, Hinman Box 4571, New Mexico, provides an excellent opportunity genic limestone nodules. Unit 2 represents a Hanover, NH 03755; Spencer G. Lucas, New to observe the migration rates of eolian features. transitional facies of thin limestones deposited Mexico Museum of Natural History, 1801 The field, covering approximately 0.6 km2, con- during short, shallow marine episodes, and fine- Mountain Rd. NW, Albuquerque, NM 87104; sists of active transverse and parabolic sand grained red beds, mainly of pedogenic origin. and Dennis R. Braman, Royal Tyrrell Museum dunes, indicating consistent west-southwest This sequence is strikingly similar to the Bur- of Palaeontology, Box 7500, Drumheller, AB winds. Barchan and barchanoid forms are less sum Formation, to which we assign it. Unit 3 is T0J 0Y0, Canada abundant. Eolian formations typically caused by the Wolfcampian Abo Formation composed of The Upper Cretaceous Tohatchi Formation is at more complex wind patterns, such as reversing, red mudstones and siltstones with intercalated least 160 m of nonmarine siliciclastic strata seif, or star dunes, are absent. Bare areas found conglomerates, sandstones, and pedogenic hori- exposed in western New Mexico along the among central interdune spaces demonstrate a zons. The presence of Bursum strata directly southeast and east flank of the Chuska Moun- limited amount of sand in relation to the above Desmoinesian limestones suggests a pro- tains. The Tohatchi Formation conformably amount potentially transported by local winds. found hiatus between units 1 and 2 equivalent overlies the Menefee Formation, is uncon- Los Medaños is located adjacent to a much larg- to at least Missourian time. Indeed, the Madera– formably overlain by the Paleogene Deza Mem- er set of dunes stabilized by vegetation. These Bursum contact in Fryingpan Canyon is marked ber of the Chuska Sandstone and consists of a dune areas are likely sources for the active by a 3-m-thick pedogenic calcrete at the Bursum lower, sandstone-dominated member and an dunes. base directly overlying cherty marine limestone upper, mudstone-dominated member. A signifi- Annual to semi-annual aerial photographs of at the Madera top, indicative of a profound cant change in sandstone lithology and bedform Los Medaños since the early 1980s show that unconformity. The presence of a Late Pennsyl- at the base of the Tohatchi Formation is a map- dunes are forming and migrating in recent vanian unconformity in the southern Cooke’s pable contact and justifies continued recognition years. From 1990 to 1996, dune crests shifted Range is further evidence of a regional tectonic of the unit as a distinct formation. west-southwest a total of 78 m over the 6-yr event(s) in the Orogrande Basin during Mis- Dinosaur fossils found throughout the period. Active perimeter dunes containing more sourian time. Tohatchi Formation indicate a Late Cretaceous vegetation move more slowly than formations age, and extensive palynomorph assemblages in the center. Mesquite and other small trees, refine this age assignment to early Campanian. located sparsely throughout the field, develop The presence in the Tohatchi Formation of such roots from the trunk as they are buried by PETROGRAPHIC ANALYSIS OF REDUC- species as Accuratipollis lactiflumis, Brevimonosul- advancing dunes. As the dunes continue to TION ZONES IN THE RED BEDS OF THE cites corrugatus, Callialasporites dampieri, Micro- migrate, exposing the vegetation, roots develop ABO FORMATION, NEW MEXICO, by Joel foveolatosporis pseudoreticulatus, Periretisynol- bark. The mesquite and other trees may be help- P. Bensing and Peter S. Mozley, Department of porites chinookensis, and Rugubivesiculites reduc- ful in understanding dune movement beyond Earth and Environmental Science, New Mexi- tus suggests links to upper Santonian the photographic record. co Institute of Mining and Technology, Socor- assemblages of the Milk River and lower Eagle ro, NM 87801 Formations of Alberta–Montana. However, Reduction features are commonly observed in other Tohatchi species such as Aquilapollenites red beds, including the Abo Formation, yet are attenuatus, A. trialatus, A. turbidus, Pulcheripollen- THE BURSUM FORMATION AND A LATE still not fully understood. In particular, the exact ites krempii, and Tricolpites reticulatus are more PENNSYLVANIAN UNCONFORMITY IN nature of the mineralogical changes accompany- closely related to assemblages from the Pakow- THE SOUTHERN COOKE’S RANGE, ing reduction are poorly understood. By using ki Formation and Judith River Group of Alberta LUNA COUNTY, NEW MEXICO, by Karl the electron microprobe to gain back-scattered and the Claggett and Judith River Formations of

48 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 Montana. The palynomorph assemblages in the expose Proterozoic metasedimentary rocks cut In contrast, three K-feldspar samples collected Tohatchi Formation thus fall within the by several plutons ranging in age from 1.6 to 1.2 from basement penetrating petroleum explo- Aquilapollenites senonicus interval zone of early Ga. The age of the source rocks and the age of ration well cuttings in the Las Vegas Basin, east Campanian age. Therefore, the Tohatchi Forma- deposition were investigated using LA-MC- of the range-bounding Montezuma fault zone, tion is not, as has been thought for 50 yrs, a cor- ICPMS U/Pb isotope analysis of individual show that basement unroofing in this area relative of part of the upper Campanian Pic- detrital zircons. Our previously reported elec- occurred later, between ~700 and 600 Ma. Dis- tured Cliffs–Fruitland–Kirtland Formations suc- tron microprobe ages of detrital monazite parity in thermal histories between these sam- cession to the east. Instead, the Tohatchi ranged from 2.3 to 1.7 Ga, but low Pb concentra- ples suggests that the basin samples remained Formation is the uppermost part of the tions resulted in 50–150 Ma uncertainties. approximately 5 km deeper (and subsequently Mesaverde Group in western New Mexico, Zircons from one of these metasedimentary hotter) than the Sangre de Cristo basement sam- younger than the underlying Allison Member of rocks were analyzed in order to better constrain ples until the basin K-feldspars closed to 40Ar the Menefee Formation locally, and older than the age of the source rocks and the depositional loss (150°C) around 600 Ma. However, by Mis- the late Campanian turnaround of the Cliff age. A 35-micrometer laser beam was used to sissippian time, these rocks resided at a similar House– Pictured Cliffs shoreline to the east. analyze zircon cores. We analyzed 49 different structural position below the extensive carbon- zircons, which have a range of 207Pb/206Pb ages ate deposits that unconformably overly the Pro- from 1,655 ± 37 to 1,892 ± 62 Ma with a mean of terozoic basement across much of New Mexico. 1,725 Ma. The 1σ uncertainties range from 18 to Thermochronologic and geometric constraints PROBLEMS WITH THE EXISTING STRATI- 62 Ma with a mean of 25 Ma. Histograms indi- implicate fault initiation with east-side-up GRAPHIC NOMENCLATURE OF THE cate a main peak of ages at 1,725 Ma with small- motion at ca. 700 Ma to bring the Las Vegas SANTA FE GROUP IN THE ESPAÑOLA er peaks at 1,680 Ma, 1,792 Ma, and 1,841 Ma. Basin samples up to the same structural level as BASIN AND SUGGESTED REVISIONS, by One grain yielded a Late Archean age of 2,878 ± the Sangre de Cristo samples before Mississippi- Daniel J. Koning, [email protected], 26 Ma. an sedimentation. Thus, the Laramide Montezu- Rt. 1, Box 28A, Santa Cruz, NM 87567 Source rocks for the Burro Mountains ma fault that presently separates these samples Recent mapping of the Santa Fe Group near metasedimentary rocks therefore contain zir- represents a reactivation of this preexisting Neo- Española, New Mexico, elucidates the stratigra- cons that range in age from 1.65 to 2.88 Ga. Most proterozoic structural weakness. phy of the Española Basin and underscores Mazatzal province source rocks are thought to Ten additional step-heating analyses were some long-standing problems regarding current be <1.7 Ga, whereas Yavapai basement rocks are conducted on metasomatic K-feldspar separated stratigraphic nomenclature. The lower 180–200 as old as 1.85 Ga and may be providing some of from hydrothermally altered igneous and meta- m of the Chamita Formation type section, locat- the source material for these samples, though morphic basement rocks in the Pecos River Val- ed southeast of Black Mesa and west of the Rio Mojave or Wyoming province or other sources ley near the Picuris–Pecos fault zone. Alteration Grande, is similar to the Cejita Member of the cannot be ruled out. The metasedimentary rocks is characterized by K-feldspar ± epidote replace- Tesuque Formation, particularly in its fluvial were deposited between 1,655 Ma (the youngest ment of albite in host lithologies, and was facili- facies and clast composition (corresponding to detrital zircon) and 1,633 Ma (the age of a cross- tated by fluid migration along brittle structures Lithosome B of Cavazza, 1986). At the Chamita cutting diabase), which is consistent with the including fractures and zones of brecciation. 40 39 Formation type section, >200 m of granite-rich ages of other Mazatzal province volcano-sedi- Ar/ Ar age spectra from these samples are piedmont sediment (Lithosome A of Cavazza, mentary sequences. Comparison of these data complex and commonly exhibit intermediate 1986) conformably overlies Lithosome B. Bios- with those from detrital zircon studies in adja- age maxima. The nature of these intermediate tratigraphic data, geologic mapping, and com- cent areas in eastern Arizona indicates that max- age maxima is enigmatic but may be due to positional similarities support the correlation of imum age of deposition, 1,655 ± 37 Ma, is the post-crystallization diagenetic or hydrothermal much of the upper Tesuque Formation east of same as for sedimentary rocks in the Little Dra- alteration, or mechanical fracturing of diffusion the Rio Grande (particularly northeast of the goon Mountains (1,655 ± 4 Ma). The detrital zir- domains either by natural processes or laborato- San Juan Indian Reservation) to the lower and con ages in the Burro Mountains are significant- ry heating procedures. Thermal histories from middle Chamita Formation type section. This ly older than those from the Cochise Block these samples suggest a range in the timing of correlation, and the lack of significant sedimen- (1,697–1,729 Ma) and Pinal Block (1,678–1,731 mineral growth between ca. 1,000 Ma and ca. tologic differences between the Chamita Forma- Ma, with one grain at 2,448 Ma) in southeast 600 Ma. These data indicate two episodes of tion type section and upper Tesuque Formation, Arizona. This probably reflects a greater contri- metasomatism; one before ~1,000 Ma while the raises significant concerns about whether to bution from Yavapai province igneous rocks as basement was regionally ~300°C, and a second retain the Chamita Formation as a member of well as from older continental rocks either in the that initiated at ca. 700 Ma when the basement the Tesuque Formation or abandon it altogether. continental interior or possibly from a source was relatively cool at ~150°C. Additionally, In addition, I suggest differentiating the other than North America. basement K-feldspars from opposing sides of Tesuque Formation into members using compo- the Picuris–Pecos fault do not display evidence sitional and textural criteria; this would retain for significant vertical offset during the Neopro- the current Chama–El Rito, Ojo Caliente Sand- terozoic, and metasomatic fluids, therefore, 40 39 stone, and Cejita Members. However, the AR/ AR THERMOCHRONOLOGICAL infiltrated fractures and zones of brecciation Nambé, Skull Ridge, and Pojoaque Members are CONSTRAINTS ON THE TIMING OF formed largely by strike-slip deformation. The less lithologically distinct and difficult to differ- BASEMENT EXHUMATION AND META- later episode of metasomatism may be contem- entiate south of Tesuque Pueblo and north of the SOMATISM IN THE SOUTHERN SANGRE poraneous with the initiation of exhumation at Santa Cruz River. The Nambé, Skull Ridge, and DE CRISTO RANGE, NEW MEXICO, by ca. 700 Ma. Deformation and metasomatism in Pojoaque Members each contain Lithosomes A Robert E. Sanders, [email protected], Depart- northern New Mexico during these times could and B; thus, differentiating this sediment using ment of Earth and Environmental Science, represent inboard tectonic processes related to the lithosome approach of Cavazza (1986) New Mexico Institute of Mining and Technol- the rifting of Rodinia. would be more objective and more regionally ogy, Socorro, NM 87801; and Matthew T. Hei- applicable. zler, New Mexico Bureau of Geology and Min- eral Resources, New Mexico Institute of Min- ing and Technology, Socorro, NM 87801 GEOLOGIC MAP OF THE ALBUQUERQUE– 40Ar/39Ar step-heating analyses of K-feldspar RIO RANCHO METROPOLITAN AREA DETRITAL ZIRCON U/PB AGES FROM PRO- from crystalline basement rocks located beneath AND VICINITY: STRUCTURAL AND TEROZOIC METASEDIMENTARY ROCKS the Precambrian–Paleozoic unconformity in the STRATIGRAPHIC FRAMEWORK OF THE IN THE BURRO MOUNTAINS, MAZAT- southern Sangre de Cristo Mountains, New ALBUQUERQUE BASIN, NEW MEXICO, ZAL PROVINCE, SOUTHWEST NEW MEX- Mexico, reveal complex exhumation. Thermal by Sean D. Connell, [email protected], New ICO, by Jeffrey M. Amato, Amos Sanders, histories deduced from Multiple Diffusion Mexico Bureau of Geology and Mineral Department of Geological Sciences, New Mex- Domain modeling of eight igneous and meta- Resources—Albuquerque Office, New Mexico ico State University, Las Cruces, NM 88003; morphic K-feldspars collected from rocks Institute of Mining and Technology, 2808 Cen- and George Gehrels, Department of Geo- between Santa Fe and Las Vegas display a dom- tral Ave. SE, Albuquerque, NM 87106 sciences, University of Arizona, Tucson, AZ inant 1,000–800 Ma cooling signature. The Fourteen geologic maps by the New Mexico 85721 ~150°C temperature decrease during this time is Bureau of Geology and Mineral Resources and The Burro Mountains in southwest New Mexico interpreted to represent 4–5 km of denudation. U.S. Geological Survey, and drillhole data were

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 49 compiled into a 1:50,000-scale map encompass- growths of cristobalite and feldspar. Cristobalite Busted Butte, Nevada. We have investigated ing 2,200 km2 of the Albuquerque–Rio Rancho content decreases as tridymite content increases petrophysical controls on deformation in small- metropolitan area and vicinity. Sediment-distri- in overlying non- to moderately welded unit displacement faults in these areas. Fractures and bution patterns and paleocurrent data docu- Qbt1v-u (“upper”). Qbt1v-u and moderately deformation bands are found at both sites. The ment south-southeast-flowing paleorivers asso- welded Qbt2 contain tridymite, alkali feldspar, primary controls on which structure forms in an ciated with the ancestral Rio Puerco fluvial sys- and lesser cristobalite as crystals in pore spaces, ignimbrite unit are the number and strength of tem (Arroyo Ojito Formation, To) and provide suggesting an increase in vapor-phase alter- grain contacts in the groundmass, which are geologic constraints on ground-water-flow ation. In the western portion of the study area, inversely proportional to porosity and directly anisotropy. The To dominates the upper Santa closer to the source of the Bandelier Tuff, the related to degree of welding and postdeposi- Fe Group basin fill. To drainages flowed upper part of Qbt1v-u is welded together with tional crystallization. Low-porosity, welded obliquely toward the basin axis where they unit Qbt2. In the eastern portion of the study units deform by transgranular fracture; high- entered the south-southwest-flowing axial Rio area, non-welded Qbt1v-u is overlain by par- porosity, glassy, non-welded units deform by Grande fluvial system (ARG). Basin-margin tially to moderately welded Qbt2. cataclasis and pore collapse within deformation unconformities generally become gradational bands. Moderately high porosity, non-welded toward depocentral areas. Northwestern basin- STRUCTURE AND TECTONICS units with postdepositional crystallization margin faults may have been active before 19 deform by either cataclasis with associated pore Ma, resulting in local stripping of formerly STRUCTURAL GEOLOGY OF THE NORTH- collapse, or by fracture, depending on local vari- widespread Oligocene strata. The lack of mid- CENTRAL TO NORTHEASTERN POR- ations in clast size and nature of crystallization. dle-member (To) deposits on the footwall of the TION OF LOS ALAMOS NATIONAL LAB- Clast- and pore-size reduction in deformation San Ysidro fault indicates that erosion of the ORATORY, NEW MEXICO, by Alexis Lavine, bands is significant, producing indurated zones northwestern basin margin occurred between [email protected], Claudia J. Lewis, Danielle of clay-sized material. Preferential wetting, late Miocene and Pliocene time. Widespread Katcher, Jamie N. Gardner, and Jennifer Wilson, inferred to promote alteration and cementation, basinal aggradation diachronously ceased Environmental Geology and Risk Analysis is observed in many deformation bands. Many ~2.5–0.8 Ma, probably as a consequence of dif- Group, EES-9, Los Alamos National Laborato- of these bands are also locally rich in smectite ferential tilting and changing sedimentation ry, Los Alamos, NM 87545 and/or cemented by calcite. We therefore inter- rates and patterns within the basin. Conglomer- Geologic mapping in the north-central to north- pret variably altered fault-zone material as evi- atic deposits were largely restricted to basin eastern portion of Los Alamos National Labora- dence of preferential fluid flow through defor- margins before Pliocene time. The coarse- tory revealed small faults and broad zones of mation bands in the vadose zone, which we grained upper member (To) subsequently pro- deformation that have little potential for seismic infer to be the result of enhanced unsaturated permeability due to pore-size reduction in graded across much of the western basin. The surface rupture. The 7.5 km2 area lies ~1 km east deformation bands. This is significant for mod- ARG flowed within 2 km of the Sandia Moun- of the Pajarito fault system, ~2.5 km south of the els of fluid flow and transport, since most tains frontal fault system before Pleistocene Sawyer Canyon fault, and within a zone of assume matrix-dominated flow through non- time. Piedmont deposits derived from rift-flank inferred subsurface, pre-Bandelier Tuff faults. welded ignimbrites, disregarding potential uplifts prograded west and buried much of the Mapped changes in welding and crystallization effects of small-displacement faults. ARG succession by early Pleistocene time. in the Tshirege Member of the Bandelier Tuff Between 1.2 and 0.8 Ma, the ARG had migrated coincide with or parallel stratigraphic contacts, toward the basin center when incision began providing large-scale, planar markers for deter- forming the Rio Grande valley. mining structural offset. Fault and fracture FIRST YEAR’S DATA FROM TILTMETERS zones include: 1) an ~180-m-wide zone of abun- INSTALLED AROUND THE MARGINS OF dant fractures and faults that range in width HISTORIC UPLIFT, CENTERED ABOVE from 1 to 60 cm, and have a mean strike of N12E STRATIGRAPHY OF UNITS Qbt1g–Qbt3 OF THE SOCORRO MAGMA BODY, RIO ± 26° and mean dip of 87 ± 5º; 2) a 60-m-wide THE TSHIREGE MEMBER OF THE BAN- GRANDE RIFT, NEW MEXICO, by David W. fault zone with ~1.2 m of down-to-the-north- DELIER TUFF IN THE NORTH-CENTRAL Love, Bruce Allen, Richard Chamberlin, New west displacement; 3) a 15–20-cm-wide fault TO NORTHEASTERN PORTION OF LOS Mexico Bureau of Geology and Mineral that is oriented N16E, 86E and consists of dense- ALAMOS NATIONAL LABORATORY, Resources, New Mexico Institute of Mining ly spaced deformation bands; and 4) three small NEW MEXICO and Technology, Socorro, NM 87801; and , by Danielle K. Katcher, dkatch- (<1 m of vertical displacement) faults in the William Haneberg, Haneberg Geoscience, 4434 [email protected], Alexis Lavine, Claudia J. Lewis, western portion of the map area. Fault zones 1 SE Land Summit Court, Port Orchard, WA Jamie N. Gardner, and Jennifer E. Wilson, Envi- and 2 coincide with a zone of shallower dip that 98366 ronmental Geology and Risk Analysis Group, trends N10–15E, and could accommodate up to EES-9, Los Alamos National Laboratory, Los 8 m of down-to-the-west displacement across The elliptical pancake-shaped Socorro magma Alamos, NM 87545 ~500 m. No stratigraphic markers are present body is inferred to extend over 3,400 km2 at a We conducted detailed stratigraphic studies as where fault 3 is exposed; however, 3-D structur- depth of ~19 km with an estimated thickness of part of a larger geologic mapping project to al analysis suggests that it may be associated 0.1 km: thus yielding a volume of about 340 km3 assess seismic hazards to the north-central to with distributed down-to-the-east deformation (Balch et al., 1997). Since 1909 the rate of historic northeast portion of Los Alamos National Labo- accommodating 5–6 m of displacement over uplift near the center of the Socorro magma ratory. Units Qbt1g–Qbt3 of the Tshirege Mem- ~300 m. Changes in dip of Tshirege Member body at San Acacia has been between 1.8 mm/yr ber of the Bandelier Tuff are differentiated by units may result from distributed deformation and 4 mm/yr (Larsen et al., 1986; Fialko and the degree of welding, crystallization, weather- or deposition over paleotopography. Simmons, 2001). Using vertical uplift rates from ing characteristics, and distinctive mineralogy. previously published studies, we calculate aver- To better understand lateral variations in stratig- age tilt rates on the flanks of the uplift to be raphy, we measured four stratigraphic sections ~0.12 microradians (µrad) per year (~1° in 145 and collected samples for petrographic and X- DEFORMATION BANDS IN NON-WELDED ka). Above the Socorro magma body, fault ray diffraction analysis. Non-welded Qbt1g is IGNIMBRITES: PETROPHYSICAL CON- blocks of the early Rio Grande rift are numer- vitric (50–70% glass). The top of Qbt1g is TROLS ON THEIR OCCURRENCE AND ous, strongly extended, and variably tilted. marked by a “vapor-phase notch,” above which IMPLICATIONS FOR FLUID FLOW, by Jen- However, the long axis of the Socorro magma glass is altered to cristobalite, tridymite, and nifer E. Wilson, [email protected], Laurel B. Good- body is approximately coincident with the alkali feldspar in units Qbt1v through Qbt3. The win, [email protected], Department of Earth active axis of the rift as defined by Quaternary non-welded unit Qbt1v-c (“colonnade”) lies and Environmental Science, New Mexico grabens that outline the southern end of the directly above the vapor-phase notch and has a Institute of Mining and Technology, Socorro, Belen Basin and the much narrower graben of distinctive columnar appearance, due to cooling NM, 87801; and Claudia J. Lewis, clewis@ the Socorro Basin. joints and/or tectonic fractures where the unit is lanl.gov, Los Alamos National Laboratory, With matching funds from the New Mexico indurated by devitrification and vapor-phase EES-9, MS D462, Los Alamos, NM 87545 Department of Public Safety, we installed tilt- alteration minerals. We hypothesize that the Faults in ignimbrites are of interest for a variety meters on three margins of the historic uplift. main cementing agents in Qbt1v-c are cristo- of reasons, including their potential impact on The solar-powered meters are capable of meas- balite and Fe-oxide. Devitrification is recog- fluid flow and transport through vadose zones uring 0.1 µrad differences in tilt for extended nized by axiolitic and minor spherulitic inter- in places like Los Alamos, New Mexico, and periods. We anticipate that monitoring over sev-

50 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 eral years might provide insight into the uplift to southwest away from recharge areas in the es to ground water leakage need to be account- process and interaction of magmatic stresses Sacramento Mountains. ed for as the municipality considers the benefits with long-term tectonic stresses as defined by of an acequia-lining plan. upper crustal fault blocks. We selected tiltmeter locations to the north (Sevilleta 1) and south SOILS AND CO2 (Tech 1) that were away from Quaternary scarps GROUND WATER GEOLOGY OF TAOS and within graben blocks in order to minimize VALLEY, by Tony Benson, AnthonyBenson SOIL GAS CO2 EMISSIONS OVER THE rift-related block rotation. The western station @msn.com, and Elsbeth Atencio, University of BRAVO DOME FIELD IN THE AMISTAD (Silver Creek 1), however, is on a large active New Mexico, Taos, NM 87571 AREA OF NEW MEXICO, by Kristie McLin, west-tilting half graben (La Jencia Basin) where Water well drillers’ logs (after accurately locat- Department of Earth and Environmental Sci- tectonic tilt and magmatic tilt should be addi- ing the wells with GPS equipment) were used to ence, New Mexico Institute of Mining and tive. Available equipment limited the installa- map the ground water table and subsurface Technology, Socorro, NM 87801 tion to depths of 3–4 m in alluvium. structure. Basalt and clastic interbeds allow The Bravo Dome field, located in Union and Dataloggers record tilts, temperatures, and drillers’ ample descriptions to be correlated Harding Counties, New Mexico, is a large precipitation (only at Silver Creek) every 30 sec- from the Rio Grande gorge to the town of Taos. underground carbon dioxide reserve that is one onds and store averaged data every 20 minutes. The main feature herein, called the Airport of the largest CO accumulations in North The tilt data show diurnal fluctuations in the 2 arch, is a northeast-trending uplift with surface America. This field provides jobs for about 100 range of tenths of µrad that apparently are relat- expression. Numerous normal faults have been people, as well as $1.8 million in tax revenues ed to Earth tides. Longer-term trends of tens of mapped, especially on the east flank of the arch. and royalties for the state annually. The carbon µrad are contrary to expectations and may be Four north-trending faults seen at the surface in dioxide is primarily used to enhance recovery in due to several factors, including settling after Los Cordovas can be traced northward and the oil fields of southeast New Mexico and west- installation. Surface waves from distant earth- southward in the subsurface. Other faults have ern Texas. Although the region’s economy relies quakes as small as magnitude 5.1 temporarily been mapped on the Hondo Mesa and Blueber- heavily upon the production of carbon dioxide, affect the 20-minute averages and show that ry Hill. Faults appear to interfere with the later- residents living on the eastern boundary of the some tiltmeter rotation matches Rayleigh-wave al flow of ground water westerly toward the Rio field have expressed concern about the health motions. Temporary reversals in tilt direction Grande gorge. effects associated with possibly elevated levels follow precipitation events at Silver Creek. Ground water recharge from streams near the of carbon dioxide. In July and August of 2002, a Sevilleta 1 continued to tilt southeast through- mountain front shows seasonal drops in water field survey was conducted to investigate the out the year. Tech 1 tilted northwest until the level and an overall drop during the last 8 yrs of possible natural leakage of carbon dioxide from end of October, when it began to tilt northeast. drought. Communities near the mountain front the Bravo Dome field on ranches near the town Silver Creek 1 tilted southeast from March until have seen water levels drop in response to the of Amistad where health related complaints August, then tilted briefly to the southwest and drought, whereas wells farther out in the valley were reported to the states environmental and northeast, and tilted west and northwest in have seen little effect. health departments. Atmospheric carbon diox- November and December. ide concentrations were continuously moni- tored using a Drager CO2 analyzer. Soil carbon HYDROGEOLOGY dioxide concentrations were measured in sever- INFLUENCE OF INFILTRATION AND EVAP- al locations as well. Ambient atmosphere con- SIMULATION OF PRE-DEVELOPMENT ORATION ON THE HYDROLOGIC BUD- tains approximately 0.036% (by volume) CO2, GROUND-WATER FLOW IN THE BASIN- GET AT THE LAS VEGAS NATIONAL and measured atmospheric CO2 concentrations FILL AQUIFER OF THE TULAROSA WILDLIFE REFUGE, NEW MEXICO, by in the study area remained consistently at BASIN, SOUTH-CENTRAL NEW MEXICO, Thomas Evans and Jennifer Lindline, Environ- 0.03%. Soil carbon dioxide concentrations by G. F. Huff, [email protected], U.S. Geological mental Geology Program, New Mexico High- ranged from 0.47% in sparsely vegetated areas Survey, New Mexico State University, Dept. lands University, Las Vegas, NM 87701 to 1.0% in densely vegetated lawns. These meas- 3ARP, Las Cruces, NM 88003 An integrated hydrogeological study was con- urements did not significantly differ from back- The U.S. Geological Survey in cooperation with ducted to characterize the soil types and to ground measurements taken approximately 20 the city of Alamogordo, New Mexico, and Hol- assess the influence of infiltration and evapora- mi north of the CO2 field. No elevated CO2 con- loman Air Force Base investigated the hydrolo- tion on the hydrologic budget for a small pond centrations were found in houses, near pipelines gy of the basin-fill aquifer in the Tularosa Basin at the Las Vegas National Wildlife Refuge in or the compressor plant. At Mammoth Moun- through construction and calibration of a northeastern New Mexico. Fieldwork was con- tain, California, soil CO2 concentrations are sig- steady-state three-dimensional ground-water- ducted in September 2002 at Melton Pond, a rep- nificantly larger (>30% by volume), yet CO2 flow model using the U.S. Geological Survey resentative pond (0.029 mi2) within the refuge related illnesses are rarely reported. We found finite-difference modular ground-water-flow surface water system. Soil sampling and infiltra- no evidence for the presence of elevated CO2 computer software MODFLOW-96. The model tion testing was completed during a time when levels, and alternative explanations must be was calibrated by matching simulated water the pond had been dry for several months. Ten found to account for the illnesses experienced in levels to available pre-development ground- soil samples were collected and separated into the Amistad area. water-level measurements. The distribution of clay, sand, and silt fractions for classification. pre-development water-level data restricts the The soils underlying Melton Pond consist pre- POSTER SESSIONS, AFTERNOON well-calibrated area of the model to the eastern dominantly of clay with minor sandy clay and PALEONTOLOGY side of the Tularosa Basin. The root mean square clay loam. A double ringed infiltration system error of the model in the well-calibrated area was used to measure infiltration rates. Infiltra- EDOPOID POSTCRANIA FROM THE RED was 6.3 m. tion rates varied from 20.0 to 144.0 mm/hr aver- TANKS MEMBER OF THE BURSUM FOR- Estimates made through model calibration aging 55.2 mm/hr. Air temperature, wind MATION, LUCERO UPLIFT, CENTRAL indicate that an amount equal to approximately speed, and relative humidity data over a 15-yr NEW MEXICO, by Susan K. Harris and 143,000 m3 per day (42,300 acre-ft per yr) of period were obtained from the Las Vegas Spencer G. Lucas, New Mexico Museum of recharge enters the basin-fill aquifer from sub- Municipal Airport and used to calculate evapo- Natural History, 1801 Mountain Rd., NW, basins that rim the Tularosa Basin. An amount ration rates. Results indicate that evaporation Albuquerque, NM 87104 equal to approximately 4–5% of annual precipi- varies from 0.45 (November) to 2.26 (June) acre- Partially articulated material that represents the tation in most sub-basins is simulated to enter ft per month totaling 15.36 acre-ft per year. Since anterior dorsal vertebral column and most of the the basin-fill aquifer as recharge. Approximately Melton Pond holds 58 acre-ft of water, the pectoral girdle of a large, primitive tem- 88% of recharge left the basin-fill aquifer as sim- results suggest that a significant amount of nospondyl was collected at NMMNH locality ulated evapotranspiration under pre-develop- water is lost to infiltration throughout the year. 4509 in the Upper Pennsylvanian (upper Vir- ment conditions. The remaining 12% was simu- This result is supported by the observed ground gilian) Red Tanks Member of the Bursum For- lated to discharge either at land surface through water seeps in the Gallinas River Canyon that mation. This locality is in the uppermost part of springs or across the southern model boundary are recharged by pond leakage. Since the hydro- the Red Tanks Member in a bed of grayish-green as ground water flow into the Hueco Bolson. geologic characteristics of Melton Pond are rep- shale and reduced mudstone, probably of palu- Generalized directions of simulated pre-devel- resentative of conditions throughout the Las dal or lacustrine origin, approximately 1.6 m opment ground water flow are dominantly west Vegas region, the significant surface water loss-

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 51 below the base of the overlying Abo Formation. conglomerate 8 m below the base of the Abo in NONMARINE BIVALVES (UNIONOIDA: Closely associated material includes a segment the Red Tanks section, in close association with ANTHRACOSIIDAE) FROM THE LOWER of articulated caudal central elements, the com- a bed containing large numbers of the bivalve PERMIAN CUTLER FORMATION OF plete left radius, and the proximal left ulna, as Permophorus. The slender, elongate neural spines NORTH-CENTRAL NEW MEXICO, by L. F. well as numerous rib fragments. are characterized by a circular cross section and Rinehart, S. G. Lucas, A. B. Heckert, K. E. Zeigler, Whereas the morphology of the intercentra an absence of anterior and posterior grooves, New Mexico Museum of Natural History, and pleuracentra is typically rhachitomous, the features diagnostic of the primitive species 1801 Mountain Rd. NW, Albuquerque, NM widely expanded ventral plate of the clavicle Dimetrodon milleri, otherwise known only from 87104; D. S. Berman, and A. Henrici, Carnegie and its narrow, rodlike dorsal process distin- the Lower Permian (middle Wolfcampian) Museum of Natural History, 4400 Forbes Ave., guish this specimen from all euskelians (higher Archer City Formation (ex Putnam Formation) Pittsburgh, PA 15213 temnospondyls), such as Eryops. Other notable in Archer County, Texas. The Welles Quarry (NMMNH locality 4825) is features of the pectoral girdle include the Pelycosaurian abundance and diversity are one of several pond/crevasse splay deposits in remarkably deep, dorsoventrally oriented gle- typically low in Desmoinesian and Missourian the Cutler Formation exposures near Loma noid fossa and the narrow, triangular coracoid strata of the Pennsylvanian. Although faunal Salazar in the Arroyo del Agua collecting area, plate, which bears a central longitudinal ridge proportions of ophiacodontids and varanopsids Rio Arriba County, New Mexico. The quarry with a large supracoracoid foramen positioned increase significantly during the Virgilian, the yields fish, amphibian, reptile, invertebrate, and midway along its length. Red Tanks material represents the only pre- plant fossils of Wolfcampian age. We describe a Temnospondyl taxonomy is dependent, to a Wolfcampian record of the progressive sphen- rich deposit of thin-shelled, freshwater bivalves large extent, on cranial and mandibular charac- acodontine genera Sphenacodon and Dimetrodon. from the quarry. The clams are preserved as ters. Thus, a generic or family level diagnosis of external and (rarely) internal casts with a few the Red Tanks material cannot be confirmed. shell fragments in laminar, gray and dark-red, However, the apparently primitive condition of micaceous muddy shale. Typical presentation is the clavicular ventral plate and dorsal process A TIME-AVERAGED TETRAPOD BONEBED: with the paired valves wide open (~180°), the suggests assignment of this specimen to the TAPHONOMY OF THE EARLY PERMIAN hinge intact, and exterior surfaces facing up. basal temnospondyl superfamily Edopoidea. CARDILLO QUARRY, CHAMA BASIN, Fish scales, coprolites, and disarticulated bones NORTH-CENTRAL NEW MEXICO, by K. E. are common in the clam-bearing facies. Zeigler, S. G. Lucas, A. B. Heckert, New Mexico The clams are equivalved, inequilateral, and Museum of Natural History, 1801 Mountain elongate oval in shape. Ligaments are external SPHENACODONTINE PELYCOSAURS Rd. NW, Albuquerque, NM 87104; A. C. Henri- and opistodetic, hinges are straight and edentate, FROM THE UPPER PENNSYLVANIAN ci and D. S. Berman, Carnegie Museum of Nat- and adductor muscle scars are absent or not pre- (UPPER VIRGILIAN) RED TANKS MEM- ural History, 4400 Forbes Ave., Pittsburgh, PA served. Length ranges from ~1 to ~23 mm. BER OF THE BURSUM FORMATION, by 15213 Umbones are slightly inflated and located at Susan K. Harris, Spencer G. Lucas, New Mexico The Early Permian Cardillo Quarry is located ~0.25 of length from the anterior end. Ornamen- Museum of Natural History, 1801 Mountain near Arroyo del Agua, in the Chama Basin in tation consists only of concentric growth ridges. Rd., NW, Albuquerque, NM 87104; Michael J. north-central New Mexico. The quarry is strati- Two variants, one with a rounded posterior end, Orchard, Geological Survey of Canada, Van- graphically low in the Cutler Formation and is and the other more blunt, may represent sexual couver, B. C. V6B 5J3 Canada; and Karl Krain- Wolfcampian in age. During excavations in dimorphs. Allometric height-to-length ratio er, Institute for Geology and Paleontology, 1979, 1980, and 2002, the remains of the (= 0.45) and overall morphology are identical to University of Innsbruck, Innrain 52, A-6020 labyrinthodont amphibian Eryops, the diadecta- the Guadalupian–Lopingian age anthracosiid, Innsbruck, Austria morph Diadectes, a captorhinid, a varanopseid Palaeanodonta parallela, known from the Lower In 1980, Fracasso (Journal of Paleontology 54: pelycosaur, and the pelycosaurs Sphenacodon Beaufort Series of the Karroo Basin in South 1237–1244) assigned localities yielding Sphena- and Ophiacodon were recovered from this locali- Africa, and the Tatarian of Russia. However, codon material from megasequence one at El ty. Numerically, the pelycosaurs dominate the because of the large temporal and geographic Cobre Canyon in the Cutler Formation of north- bonebed. Taphonomic data collected during the range differences between P. parallela and the central New Mexico a Missourian age, thereby 2002 excavations reveal that the Cardillo Quarry Welles Quarry specimens, we provisionally extending the stratigraphic range of Sphenacodon fossil assemblage is an attritional accumulation. assign the clams to Palaeanodonta cf. P. parallela. well below the Wolfcampian. However, later The bones lie within a series of three distinct, This is the first report of Palaeanodonta from the authors determined these localities to be within pedogenically modified conglomerates that also Permian of North America, and a substantial Wolfcampian age sediments of megasequence include calcrete nodules, chert, quartzite, and extension of its stratigraphic range from the mid- two. Diagnostic neural spines from the upper other siliceous pebbles. The skeletal material is dle Permian to nearly the base of the Permian. part of the Red Tanks Member of the Bursum mostly disarticulated, though a partially articu- Formation in the Lucero uplift of central New lated pelycosaur skeleton has been recovered Mexico represent the oldest definitive record of from the overbank sediments above the upper- the subfamily Sphenacodontinae. Their age is most conglomerate. Isolated skeletal elements REVISED FAUNAL LIST AND SIGNIFI- late Virgilian based on streptognathid con- and bone fragments are in various stages of CANCE OF THE UPPER TRIASSIC odonts collected from the middle third of the weathering and show differing degrees of abra- (REVUELTIAN: EARLY-MID NORIAN) member that display primitive characters of the sion. The assemblage does not appear to have SNYDER QUARRY, NORTH-CENTRAL species complex that includes the index of the been hydraulically sorted because all three NEW MEXICO, by A. B. Heckert, K. E. Zeigler, Virgilian–Wolfcampian boundary, Streptognatho- Voorhies groups are well represented. The S. G. Lucas, A. P. Hunt, and L. F. Rinehart, New dus isolatus. No stratigraphic breaks occur in the Cardillo Quarry assemblage was formed by a Mexico Museum of Natural History, 1801 upper third of the Red Tanks, strongly suggest- series of crevasse splays, and the formation of Mountain Rd. NW, Albuquerque, NM 87104 ing that the entire member, at least up to the each splay deposit followed the same sequence The Snyder Quarry, in the Painted Desert Mem- base of the overlying Abo Formation, is of Car- of events. First, basement material (siliceous ber of the Petrified Forest Formation in north- boniferous age. pebbles) was incorporated into lag deposits in a central New Mexico, is one of the richest and As many as seven localities in the Red Tanks stream, together with individual bones and most diverse Upper Triassic bonebeds discov- Member yielded elongate, anteroposteriorly bone fragments from upstream. This lag of peb- ered in the past 50 yrs. This bonebed formed, at expanded, laterally compressed neural spines bles and bones was then reworked onto the least in part, as a result of a catastrophic paleo- diagnostic of the genus Sphenacodon. Three of floodplain by crevasse splays during flooding of wildfire that we also implicate in the formation these sites, in the Carrizo Arroyo South section, the stream, and probably incorporated addition- of the well-known Canjilon Quarry and the are approximately 34 m below the base of the al bone material that was lying on the flood- recently discovered Hayden Quarry. Abo in beds of limestone conglomerate, where- plain. The mixture of bones and pebbles was The Snyder Quarry yields a diverse array of as four additional sites in the Major Ranch area subsequently buried under fine silts during vertebrates and a more depauperate inverte- are within the uppermost 13 m of the member, overbank deposition and pedogenically modi- brate assemblage. Invertebrates include a new and occur in beds of grayish-green shale and fied. Thus, the Cardillo Quarry is a classic exam- decapod crustacean, a conchostracan, and an reduced mudstone. ple of a time-averaged vertebrate fossil assem- allochthonous assemblage of the unionid Four partially articulated vertebrae were blage. bivalve “Antediplodon.” Phytosaurs that we found preserved in a matrix of limestone-pebble assign to Pseudopalatus buceros dominate the ver-

52 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 tebrate assemblage (minimum number of indi- logical variable, often used for scaling of organs, lator (theropod dinosaur), and Tetrasauropus viduals [MNI] = 11). Aetosaurs present in the biomass determination, biomechanics, and loco- (sauropod dinosaur?). The Sloan Creek site dif- quarry include Typothorax coccinarum and Des- motion. We take advantage of phytosaurs’ gen- fers from Sloan Canyon in lacking large tridactyl matosuchus chamaensis, both represented by eral similarity to extant crocodilians to attempt theropod tracks and from Peacock Canyon in diverse osteoderms (scutes) and some other to reconstruct body mass and length based on lacking Rhynchosauroides, Kouphichnium, and postcrania representing as many as five differ- measurements of the skulls and limbs of phy- putative therapsid tracks. ent individuals. A striking feature of the Snyder tosaurs from the Upper Triassic Snyder and Quarry is the relative abundance of theropod Canjilon Quarries in north-central New Mexico. dinosaurs (MNI = 4), most of which appear to be These quarries, in the Painted Desert Member of coelophysoids congeneric with Eucoelophysis, the Petrified Forest Formation (Revueltian: A NEW LOCALITY FOR MIDDLE JURASSIC previously known only from the type locality early-mid Norian) preserve catastrophic death FISH FROM THE TODILTO FORMATION, near Orphan Mesa to the east. Other vertebrates assemblages that appear to represent well dis- NORTH-CENTRAL NEW MEXICO, by A. P. are considerably rarer, and include semionotid crete populations of phytosaur populations. We Hunt, New Mexico Museum of Natural Histo- and redfieldiid fish, metoposaurid amphibians, also utilize a snout-vent measurement based on ry, 1801 Mountain Rd. NW, Albuquerque, NM a procolophonid reptile, a probable lepidosauro- an articulated skeleton from the Canjilon Quar- 87104; and A. Downs, Ruth Hall Museum of morph reptile, and possibly a xenacanth shark. ry to compare the accuracy of different equa- Paleontology, Ghost Ranch Conference Cen- Recently we determined that rauisuchian tions based on discrete limb elements. Body ter, HC 77, Box 1, Abiquiu, NM 87510 archosaurs (Postosuchus-grade) are also a rare mass estimates for Snyder Quarry phytosaurs The Middle Jurassic (Callovian) Todilto Forma- component of the fauna. range between 25 and 500 kg, with most speci- tion crops out throughout much of northwest- The tetrapod fauna of the Snyder Quarry is a mens yielding estimates of approximately ern and east-central New Mexico and south- “typical” Revueltian assemblage, including the 200–350 kg. The Canjilon Quarry sample western Colorado. The Todilto represents a vast, index taxa P. buceros and T. coccinarum. The includes fewer juveniles and more robust paralic salina. In the central part of the basin of assemblage is particularly important for many adults, including one individual that may have deposition the Todilto is composed of a lower reasons, including: (1) its exceptionally good weighed as much as 535 kg. From equations Luciano Mesa Member that is dominated by preservation of many of the vertebrates, (2) it is based on nine extant crocodilian genera, these laminated limestone and an upper Tonque the type locality of D. chamaensis, (3) it has the Revueltian phytosaurs appear to have Arroyo Member that is composed of gypsum. highest concentration of pre-Apachean (latest approached 4.5 m total body length for an ~400 The Luciano Mesa Member locally contains a Triassic) ceratosaurian dinosaurs known, and kg phytosaur. The prevalence of subadult to depauperate fauna. Holostean fish are known (4) the extraordinarily rich concentration of phy- adult phytosaurs in both quarries based on from several localities in New Mexico including: tosaur skulls and postcrania. D. chamaensis body mass estimates corroborates qualitative (1) Bull Canyon, west of Santa Rosa; (2) Warm appears to be an anagenetic descendant of the estimates of the population structure based on Springs, north of San Ysidro; (3) Lamy; (4) Mon- more common D. haplocerus, known from older skull sizes alone, thereby reinforcing the tezuma; (5) Suwanee near Grants; (6) La Liendre Chinle strata across the southwestern United hypothesis that both quarries are catastrophic near Las Vegas; (7) Echo Amphitheater, south of States. Dinosaurs are exceedingly rare in the assemblages. Chama; and (8) probably near Acoma. Despite Chinle Group (except at the Ghost Ranch Coelo- the number of localities only the Bull Canyon physis Quarry), and the presence of multiple area has produced significant numbers of speci- individuals of a single species at the Snyder mens. Quarry is a significant discovery. Indeed, NEW TETRAPOD TRACKSITE, UPPER TRI- We have located a new locality for holostean Eucoelophysis is one of the oldest known coelo- ASSIC SLOAN CANYON FORMATION, fish from the Luciano Mesa Member adjacent to physids, and its presence marks the first appear- UNION COUNTY, NEW MEXICO, by A. P. Ghost Ranch in Rio Arriba County. Fish fossils ance of a body form that would be successful Hunt, S. G. Lucas, New Mexico Museum of occur 2.1 m above the lower contact with the until the end of the Early Jurassic (with the Natural History, 1801 Mountain Rd. NW, Entrada Formation. The fish occur in a 10-cm- extinction of Syntarsus). The abundance of phy- Albuquerque, NM 87104; and M. G. Lockley, thick bed of limestone that forms a slope break. tosaurs at the Snyder Quarry, although some- Geology Department, University of Colorado The matrix is a varved, organic-rich limestone. what “typical” of Chinle localities, is still signif- at Denver, Denver, CO 80217 Beds above and below the fish level exhibit icant because the catastrophic nature of the The vast majority of tetrapod tracks in the microfolding (“crinkly” bedding), which is char- assemblage has helped us document sexual Upper Triassic Chinle Group of the western acteristic of parts of the Luciano Mesa Member. dimorphism in the phytosaur Pseudopalatus United States occur in the Rock Point sequence, The Luciano Mesa Member is 4.55 m thick at this (best shown at the nearby Canjilon Quarry) and which is of Apachean (late Norian–Rhaetian) location. will facilitate studies of the ontogeny and varia- age. These tracks are important for several rea- This locality has not been excavated. Surface tion of this genus. sons, including: (1) they represent the most collection has yielded two specimens that are diverse Late Triassic tetrapod track assemblages reposited at the Ruth Hall Museum of Paleon- in western North America; (2) they provide evi- tology at Ghost Ranch. Both specimens are lat- dence of faunas that are poorly represented by erally compressed, and the cranial and other HOW BIG WAS A PHYTOSAUR? MASS body fossils; and (3) they provide a basis for cor- areas are covered by matrix. However, based on ESTIMATES OF AN EXTINCT CLADE OF relation with the tetrapod faunas of the Late Tri- the morphology of the tail and dorsal fin and the LATE TRIASSIC ARCHOSAURS BASED assic of eastern North America, which are pre- fact that only three species of holostean fish are ON NEW MEXICAN FOSSILS AND MOD- dominantly represented by ichnofaunas. known from the Todilto, we are confident in ERN CROCODILES, by A. B. Heckert, New The Apachean Sloan Canyon Formation of assigning these specimens to Todiltia schoewei. Mexico Museum of Natural History, 1801 northeastern New Mexico contains a number of This locality has great potential to be a signifi- Mountain Rd. NW, Albuquerque, NM 87104; significant tetrapod ichnofaunas, including Pea- cant source of Jurassic fossil fish specimens. G. Hurlburt, Biology Department, California cock Canyon and Sloan Canyon. A newly dis- State University, Bakersfield, 9001 Stockdale covered tetrapod tracksite is present in the floor Highway, Bakersfield, CA 93309; J. O. Farlow, of Sloan Creek in Union County, New Mexico A LARGE HADROSAUR TRACK FROM THE Department of Geosciences, Indiana-Purdue (sec. 15 T5N R35E). The tracksite is in the middle FRUITLAND FORMATION (LATE CRETA- University, 2101 Coliseum Boulevard East, part of the Sloan Canyon Formation and covers CEOUS: CAMPANIAN), NORTHWESTERN Fort Wayne, IN 46805; and K. E. Zeigler, New a minimum area of 2,000 m2. Sediments at the NEW MEXICO, by A. P. Hunt, S. G. Lucas, Mexico Museum of Natural History, 1801 tracksite represent playa sandflat and playa New Mexico Museum of Natural History, Mountain Rd. NW, Albuquerque, NM 87104 margin deposits. 1801 Mountain Rd. NW, Albuquerque, NM Phytosaurs were the largest and most common At Sloan Creek, tracks occur at eight distinct 87104; and M. G. Lockley, Geology Depart- semi-aquatic predators of the Late Triassic. stratigraphic levels in a 1.5-m-thick interval of ment, University of Colorado at Denver, Den- Although their skulls are relatively common in red and green mottled, fine-grained sandstone ver, CO 80217 the fossil record, articulated, or even associated and siltstone. The most common tracks are iden- The Late Cretaceous (Campanian) Fruitland skeletons are extremely rare, so it has always tified as Pseudotetrasauropus (prosauropod Formation is widely exposed within the San been difficult to gauge just how large (mass or dinosaur) and occur at five levels. Less common, Juan Basin of northwestern New Mexico and length) an individual phytosaur may have been. each only occurring at a single level, are tracks represents deltaic and paludal environments. Body mass in particular is an important physio- assigned to Brachychirotherium (aetosaur?), Gral- The Fruitland contains an extensive vertebrate

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 53 fauna, but there is only one previous report of unionids is problematic. A. terraerubrae is a com- NEW MEXICO’S MOST COMPLETE SKULL tetrapod tracks. mon Revueltian unionid from Chinle Group OF THE CRETACEOUS DINOSAUR PEN- The new track is in the collections of New strata in New Mexico, Arizona, and Utah. TACERATOPS (ORNITHISCHIA: CER- Mexico Museum of Natural History and Science ATOPSIDAE)—INSIGHTS INTO THE (NMMNH P-7145). This track is preserved in a CRANIAL ANATOMY OF THE GENUS, by carbonaceous siltstone from the upper part of P. K. Reser, A. B. Heckert, and S. G. Lucas, New the formation. It is a tridactyl pedal track with a DINOSAUR FOOTPRINTS FROM THE Mexico Museum of Natural History, 1801 maximum length (through the central digit LOWER CRETACEOUS ANAPRA SAND- Mountain Rd. NW, Albuquerque, NM 87104 impression) of 800 mm and a maximum width STONE AT CERRO DE CRISTO REY, In 1978 the Museum of Northern Arizona of 870 mm. There is a small, rounded heel DOÑA ANA COUNTY, NEW MEXICO, by (MNA) excavated a remarkably complete skull impression. The track consists of three, broad E. Kappus, Department of Geological Sciences, and jaws of the ceratopsian dinosaur Pentacer- digit impressions with blunt tips. The side digit University of Texas at El Paso, El Paso, TX atops sternbergii from the Fruitland Formation in impressions are 750 and 630 mm long. 79968; S. G. Lucas, A. B. Heckert, and A. P. Hunt, northwestern New Mexico. This specimen, The majority of North American ichnofaunas New Mexico Museum of Natural History, MNA Pl. 1747, was on display in the NMMNH’s from the Late Cretaceous are dominated by 1801 Mountain Rd. NW, Albuquerque, NM Cretaceous Seacoast hall for a decade, exhibited ornithopod tracks. NMMNH P-7145 is similar to 87104 much as it was found—crushed and slightly dis- an ornithopod track in (1) being wider than Dinosaur tracks and swimming traces have articulated. Before the specimen was returned to long, (2) having wide divarification of the digit been discovered at three localities in the latest MNA, we made a mold and cast the disarticu- impressions, (3) the length of the middle digit Albian “Anapra Sandstone” (= Sarten Member lated elements and assembled them in a new, impression not being substantially greater than of the Mojado Formation, Bisbee Group) at three-dimensional resin cast mount now on dis- the side digit impressions, (4) possessing broad Cerro de Cristo Rey in Sunland Park, New Mex- play in the NMMNH’s remodeled Cretaceous digit impressions, and (5) the tips of the digit ico, southernmost Doña Ana County. At one hall. This mount preserves the specimen as it impressions being blunt. Hadrosaurs are the locality, NMMNH locality #5293, many under- was found but, unlike the previous exhibit, is only large Campanian ornithopods known from prints (over 400) of the ichnogenus Caririchnium now free-standing so that the skull can be exam- New Mexico, and so NMMNH P-7145 presum- (an ornithopod dinosaur) are preserved in con- ined from all angles. By doing this we avoided ably represents a hadrosaur. The Fruitland For- cave relief on top of a hematized, bioturbated the pitfalls associated with reconstruction or mation contains the lambeosaurine Parasaurolo- sandstone bed in the lower part of the Anapra, “correcting” deformation. The restoration phus cyrtocristatus and indeterminate hadro- ~9 m above its basal contact with the underlying allows us to re-evaluate much of the cranial saurines. However, the conservative postcrania Mesilla Valley Shale. The exposure is approxi- anatomy of Pentaceratops. The skull was almost of hadrosaurs does not allow the identification mately 400 m2, although ~150 m2 is partially entirely complete, lacking only the nasal horn. of tracks below the family level. covered by erosional debris. These tracks are tri- One significant result of this project revealed dactyl, relatively large (up to 65 cm footprint that the marginal epoccipitals cannot be placed length), have wide, blunt toes, and a square bilo- on the frill with confidence, even though this is bate heel, all of which are characteristic of the one of the best-preserved frills of Pentaceratops NONMARINE INVERTEBRATES FROM THE ichnogenus Caririchnium. known. The XI epoccipitals, however, between LATE TRIASSIC SNYDER QUARRY, CHIN- The second and third localities are two quar- the parietals at the posterior edge of the frill, are LE GROUP, CHAMA BASIN, NEW MEXI- ries adjacent to each other and are designated well preserved and confirm previous diagnoses CO, by S. G. Lucas, K. E. Zeigler, A. B. Heckert, NMMNH localities #5291 and #5292. These are of the genus. Another significant finding is that and L. F. Rinehart, New Mexico Museum of linear quarries exposing two track-bearing beds frill length is approximately 200% of “face” Natural History, 1801 Mountain Rd. NW, 9 m apart stratigraphically in the upper third of length. That is, a preorbital length of 740 mm on Albuquerque, NM 87104 the Anapra Sandstone. The lower bed of this the NMMNH cast compares with a “frill length” Near Ghost Ranch in Rio Arriba County, New second locality also preserves large Caririchnium (measured from the anterior margin of the orbit Mexico, NMMNH locality 3845 (the Snyder tracks in concave relief with small manus to the posterior edge of the parietal) of 1,480 quarry) is stratigraphically high in the Petrified impressions. Also preserved are large (40–60 cm mm, for a total skull length approaching 2.2 m. Forest Formation of the Chinle Group and of footprint length) tracks of the ichnogenus Mag- This suggests that the specimen of Pentaceratops Revueltian (Norian) age. Besides an extensive noavipes (a theropod dinosaur), characterized by from the San Juan Basin on display at the Sam fossil bone assemblage, which apparently extremely thin, pointed toes. These theropod Noble Museum of Natural History in Norman, formed in response to a catastrophic wildfire, tracks are preserved in convex epirelief in a Oklahoma (OMNH 10165), although incom- the quarry yields a small array of nonmarine hematized, bioturbated sandstone as well. The plete, is reconstructed correctly with a total skull invertebrates from mudstones and conglomer- upper bed of these two localities preserves length of approximately 3 m. Other useful com- ates a few meters above the principal bone bed. Caririchnium tracks in convex hyporelief as well parative measurements made on the cast of the A single, incomplete conchostracan from the as numerous swimming traces—possibly from MNA specimen include occipital condyle diam- mudstone has fine growth lines, a carapace reptilians. These are scratch marks and other eter (78 mm), squamosal length (1,140 mm), and length of ~5 mm and can be tentatively assigned parallel, linear grooves. These two upper dimensions of the sheared supratemporal fenes- to the polymorphic genus Lioestheria. It indicates Anapra track beds can be traced over a total tra on both the right (660 mm long, 600 mm the presence of a shallow, ephemeral pond of strike of ~750 m and as many as 350 distinct wide) and better-preserved left (370 mm long, probable high alkalinity soon after Snyder bone- footprints are exposed, including at least 12 26 mm wide) side. This is a relatively rare fossil bed accumulation. Mudstone above the main pairs of swimming traces. of Pentaceratops that includes lower jaws, and bone bed also yielded a 48-mm-long by 19-mm- The Anapra Sandstone is of latest Albian age the left lower jaw is approximately 790 mm long wide decapod specimen that is wide bodied and (Plesioturrillites brazoensis ammonite zone), so as preserved. short tailed, unlike other known Triassic crus- the Cerro de Cristo Rey tracks are slightly taceans. This animal represents the first decapod younger than the well-known late Albian track- body fossil from the Triassic of New Mexico and sites of northeastern New Mexico, which are in is the oldest eubrachyuran crab. strata equivalent to the Mortoniceras equidistans TURONIAN AMMONITES FROM THE The most abundant invertebrates from the ammonite zone, or slightly younger. At Cerro de UPPER CRETACEOUS D-CROSS MEMBER Snyder Quarry are unionid bivalves that form Cristo Rey, the dominance of ornithopod tracks OF THE MANCOS SHALE, D-CROSS an allochthonous assemblage in conglomerate and absence of sauropod tracks fits regional pat- MOUNTAIN, CATRON AND SOCORRO above the main bone bed. These unionids are terns of late Albian–Cenomanian track distribu- COUNTIES, NEW MEXICO, by P. L. Sealey elongate to ovate in outline, thin shelled, and tion consistent with North American extirpation and S. G. Lucas, New Mexico Museum of Nat- have abrupt anterior ends, about 19 radiating of sauropods before late Albian time. The delta- ural History, 1801 Mountain Rd. NW, Albu- umbonal ridges and radiating riblets on the ic/coastal plain depositional setting of the querque, NM 87104 beak. Metrics (in mm, N = 16) are length = 25– Anapra Sandstone is also remarkably similar to The zones of Prionocyclus wyomingensis, Scaphites 58, height = 10–29 (length/height ~2), and beak the track-bearing late Albian–Cenomanian ferronensis, and Prionocyclus novimexicanus are length = 7–16. They are best assigned to Ante- sandstones of northeast New Mexico, Okla- present in the D-Cross Member of the Mancos diplodon terraerubrae (Meek, 1875) sensu Good, homa, and southeast Colorado, which also have Shale at D-Cross Mountain. The ammonite 1998, though we recognize that application of a tetrapod footprint ichnofacies dominated by fauna includes Coilopoceras inflatum Cobban and the name Antediplodon Marshall, 1929 to Triassic ornithopod (Caririchnium) tracks. Hook, Prionocyclus wyomingensis Meek, Scaphites

54 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 ferronensis Cobban, and Prionocyclus novimexi- size. The Santa Fe black-on-white pottery sherds anticipate a science coordinator and an adminis- canus (Marcou). C. inflatum is abundant and is have a smaller temper size (averaging 0.15 mm trator this year), designing a permanent build- found at or near the base of the D-Cross Mem- in diameter) than the corrugated sherds (rang- ing, and developing a grant process. The insti- ber at D-Cross Mountain. All specimens collect- ing between 0.50 and 0.25 mm in diameter). tute operates under a mandate to raise one-half ed are the robust form of C. inflatum. P. wyomin- Both pottery groups are constructed of material of its funds from non-federal sources, thus gensis, although not common, is found in associ- similar in composition to local geological fundraising and marketing constitute major ation with C. inflatum. Thus far, only one sources, suggesting that they both were locally demands. We currently operate under a funding specimen of S. ferronensis has been found at D- produced. The data are still undergoing analy- match from the state of New Mexico, which sup- Cross Mountain. This is the first report of ses for statistical significance. Completion of the ports collaborative efforts by New Mexico Scaphites occurring at D-Cross Mountain. P. study is anticipated by May 2003. Bureau of Geology and Mineral Resources, novimexicanus is common and is found in the Carlsbad Office, hydrogeologist Lewis Land lower part of the section at D-Cross Mountain, and New Mexico Institute of Mining and Tech- in contrast to Cebollita Mesa and Puertecito, nology (NMT) geomicrobiologist Penny Boston. New Mexico, where it is found throughout most CLAYS THAT WORK: COMPOSITIONAL Land is currently preparing a manuscript on of the section of the D-Cross. ANALYSIS OF TRADITIONAL PUEBLO variations in ground water discharge from gyp- The collignoniceratid zone of P. wyomingensis CERAMIC SLIPS, by C. Porreca, Department sum sinkholes at Bottomless Lakes State Park, also occurs in the D-Cross Member at Cebollita of Earth and Planetary Sciences and Depart- New Mexico. An Oklahoma Geological Survey Mesa, in the Juana Lopez Member of the Man- ment of Anthropology University of New circular titled “Evaporite Karst: Engineering cos Shale northeast of Thoreau, New Mexico, Mexico, Albuquerque, New Mexico; Mailing and Environmental Problems in the United and in the type section of the Juana Lopez Mem- Address: 611 Lead Ave SW #517, Albu- States” will be published this fall. ber northwest of Cerrillos, New Mexico. The querque, NM 87102, 505-243-5965 (H) New Mexico Institute of Mining and Technol- occurrence of the standard zone of S. ferronensis This research explores what mineralogical dif- ogy created a Cave and Karst Studies Program at D-Cross Mountain indicates correlation of the ferences in clays account for their performances to provide strong intellectual and educational lower part of the D-Cross there with the lower as slip clays in the production of Native Ameri- foundations for the institute and wider speleo- part of the D-Cross at Cebollita Mesa, the lowest can traditional ceramics. Slips are thin suspen- logical community, including vigorous fundrais- part of the D-Cross at Puertecito, and the upper sions of clay in water applied to the entire sur- ing activities designed to enhance the NMT pro- part of the Juana Lopez Member of the Mancos face of a clay vessel before firing and serve as an gram and support the institute’s needs. Five Shale at the type section. The collignoniceratid adhesive base for painted designs. Organic new cave and karst graduate students will be zone of P. novimexicanus also occurs in New paints adhere to some of these clay slips during admitted in fall 2003 under Boston’s direction. Mexico in the D-Cross Member at Carthage, firing, but not to others. The clays for this study Riley, Puertecito, Cebollita Mesa and in the are derived from fluvial mudstones in the Juana Lopez Member at the type and reference Eocene Diamond Tail Formation in the Galisteo sections. The P. wyomingensis and S. ferronensis Basin, north-central New Mexico. Random sam- CAVE AND KARST STUDIES AT THE zones are of late middle Turonian age, and the P. ples were collected within massive, bioturbated, BEGINNING OF THE 21ST CENTURY: THE novimexicanus zone is of late Turonian age. floodplain mudstone facies where the clay min- NEW MEXICO CONNECTION, by Louise D. eralogy can vary significantly over short dis- Hose, [email protected], National Cave and ARCHAEOLOGY tances. Although there are multiple variables to Karst Research Institute, 1400 University Dr., be considered, this research focuses on evaluat- Carlsbad, NM 88220 A COMPARISON OF TEMPER MATERIAL ing what mineralogical differences in the clays Once mostly dismissed as the homes of unpleas- IN SANTA FE BLACK-ON-WHITE AND could account for their function as slips and ant guano deposits, curious but economically CORRUGATED POTTERY SHERDS WITH how the mineralogical differences relate to their worthless mineral displays, and eccentric LOCAL GEOLOGY FORMATIONS AT geological origin. Mineralogical variability can adventurers, caves and the karst landscapes TECOLOTE PUEBLO (LA 296), by T. Hard- result from primary depositional variations containing them have come into the scientific esty, R. Mishler, Southwest Studies Program, and/or effects of Eocene floodplain weathering. research mainstream during the last decade. New Mexico Highlands University, P.O. Box X-ray diffraction was used to assess the chemi- First-tier journals recently published both refer- 9000, Las Vegas, NM 87701; and J. Lindline, cal composition of the clay samples and to inter- eed papers and summary articles about speleo- Environmental Geology Program, New Mexi- pret the possible causes of the performance dif- logical research. Numerous television documen- co Highlands University, P.O. Box 9000, Las ferences. Preliminary results suggest that slip taries have focused the American public on cave Vegas, NM 87701 clays containing a larger smectite to illite ratio resources, touting cancer-fighting microbes and A petrographic analysis of Santa Fe black-on- retain an organic paint better than those clays Martian ecosystem analogues. State surveys white pottery sherds, corrugated pottery sherds, with relatively less smectite. increasingly look to speleologists and cavers for and local geologic materials at Tecolote Pueblo help solving water contamination and geoengi- (LA 296) in northeastern New Mexico was con- CAVES AND KARST neering problems. ducted to determine provenience of manufac- Work in New Mexico has frequently led the ture of the pottery. This study focused on the AMERICA’S NATIONAL CAVE AND KARST changing respectability toward speleology and temper portions of the sherds and the non-clay RESEARCH INSTITUTE 2003—THE GEAR- karst research. The discovery of Lechuguilla portions of the geologic formations, those frac- ING UP PHASE, by L. D. Hose, LHose@cemrc Cave (Carlsbad Caverns National Park), the tions measuring > 0.10 mm in diameter. Temper .org, Z. C. Bailey, National Cave and Karst world’s most spectacular cave-find in the sec- minerals included quartz, plagioclase feldspar, Research Institute, 1400 University Dr., Carls- ond half of the 20th century, ignited the public potassium feldspar, biotite, muscovite, calcite, bad, NM 88220; L. Land, New Mexico Bureau and scientific interest in caves. Recognition of hornblende, epidote, and pyroxene. Temper of Geology and Mineral Resources, CEMRC, enormous biomass below the surface of the material also included a variety of lithic frag- 1400 University Dr., Carlsbad, NM 88220; and earth and the accompanying explosive interest ments including granite, siltstone, aphyric P. Boston Department of Earth and Environ- in geomicrobiology has led geologists to look to basalt, and hornblende- and augite-porphyritic mental Science, New Mexico Institute of Min- caves as windows to this fascinating, potentially basalt. Distinguishing optical and crystallo- ing and Technology, Socorro, NM 87801 valuable world. Lechuguilla Cave has served as graphic properties of minerals and lithic frag- America’s National Cave and Karst Research the most significant, natural geomicrobiology ments were noted, such as grain size, grain Institute, established by the U.S. Congress as a laboratory. shape, and twinning. Point count analysis was National Park Service entity, began its “gearing Changing demographics have forced atten- also conducted on each sample to calculate up phase” in December 2002 following a 2.5 yr tion toward karst. Karst and pseudokarst lands, modal percentages of the geologic constituents development stage. Permanent director Louise such as the Appalachia, Ozarks, and New Mex- within each sample group. Qualitative and Hose has established an institute office in Carls- ico, constitute some of the most impoverished quantitative analyses have revealed similar geo- bad, New Mexico. Interim director, Zelda Bailey, and sparsely populated regions of the country. logic materials within all three groups and simi- continues to work on development issues from This relationship is a natural consequence of lar ranges of amounts of each temper material the Denver National Park Service office during two common characteristics of karst.....poor soil within the pottery samples. The data indicate this transition time. and few surface streams. Today, industry and that the Santa Fe black-on-white and corrugated The director’s current efforts include initial suburbia invade karstlands, and humans pottery sherds are distinguished only by temper operational setup, recruiting staff positions (we increasingly impact formerly rural karst regions.

May 2003, Volume 25, Number 2 NEW MEXICO GEOLOGY 55 Americans can no longer ignore the 20% of our the primary component of a rare speleothem rial contains silicon. It is known that magnesium country and New Mexico underlain by karst. type referred to as a cave balloon. Hydromagne- silicates such as trioctahedral smectite form in site cave balloons form from moonmilk and magnesium-rich cave environments. In addi- have an interior filled with gas, likely carbon tion, in laboratories hydromagnesite has been dioxide, air, or oxygen. A carbon dioxide interi- used as a template for the synthesis of smectite. ORIGIN OF HYDROMAGNESITE CAVE or would be counter-productive to carbonate We believe that the amorphous-like material BALLOONS: CLUES FROM HIGH-RESO- mineral growth. Hydromagnesite moonmilk between the hydromagnesite platelets may be a LUTION TRANSMISSION ELECTRON may be closely associated with microbial activi- hydrated magnesium silicate-like trioctahedral MICROSCOPY, by P. P. Provencio, Sandia ty, helping to explain the source for a gas-filled smectite. Such a material could contribute to the National Laboratories, Albuquerque, New balloon interior. To further understand the ori- formation of hydromagnesite balloons in two Mexico 87185; and V. J. Polyak, Department of gin of this rare and fascinating speleothem, we ways: (1) the material could act as a lubricating Earth and Planetary Sciences, University of conducted a cross-section examination of a medium allowing the platelets to move with New Mexico, Albuquerque, NM 87131 hydromagnesite balloon wall using high-resolu- expansion and contraction of the balloon, and Hydromagnesite, a platy hydrated magnesium tion transmission electron microscopy (2) the material could provide a shield for the carbonate mineral commonly forming sticky (HRTEM). HRTEM reveals fibrous amorphous- hydromagnesite from the possibly corrosive pastes (moonmilk) in dolostone-hosted caves, is like material between the hydromagnesite nature of the balloon’s interior environment. plates. Elemental analysis reveals that this mate-

NMGS abstracts author index

Allen, B., p. 50 Ghrefat, H. A., p. 47 Land, L. A., pp. 41, 55 Phillips, E. H., p. 46 Amato, J. M., p. 49 Goble, R. J., p. 46 Lavine, A., p. 50 Polyak, V. J., pp. 41, 56 Asmerom, Y., p. 41 Goff, F., p. 46 Lerner, A. J., p. 44 Porreca, C., p. 55 Aster, R., p. 47 Goodell, P. C., p. 47 Lewis, C. J., p. 50 Provencio, P. P., p. 56 Atencio, E., p. 51 Goodwin, L. B., p. 50 Libed, S. A., p. 44 Rasmussen, J. B. T., p. 41 Bailey, Z. C., p. 55 Guan, H., p. 46 Lindline, J., pp. 51, 55 Reiter, M., p. 47 Bensing, J. P., p. 48 Hall, S. A., p. 46 Love, D. W., p. 50 Reser, P. K., p. 54 Benson, T., p. 51 Haneberg, W., p. 50 Lucas, S. G., pp. 43, 44, 45, 48, 51, Rinehart, L. F., pp. 52, 54 Berman, D. S., p. 52 Hardesty, T., p. 55 52, 53, 54 Rye, R. O., p. 42 Boles, J. R., p. 42 Harris, S. K., pp. 51, 52 Lockley, M. G., p. 53 Sanders, A., p. 49 Boston, P. J., pp. 42, 55 Heckert, A. B., pp. 44, 52, 53, 54 Lueth, V. W., p. 42 Sanders, R. E., p. 49 Bowman, R. S., p. 46 Heizler, M. T., p. 49 Mahoney, C., p. 48 Schulze-Makuch, D., p. 46 Braman, D. R., p. 48 Henrici, A. C., p. 52 McIntosh, W. C., p. 46 Scott, L. A., p. 45 Carr, T. D., p. 44 Hill, C. A., p. 42 McLemore, V. T., p. 42 Sealey, P. L., p. 54 Chaney, D. S., p. 43 Hose, L. D., p. 55 McLin, K., pp., 47, 51 Shafike, N., p. 46 Chamberlin, R., p. 50 Huff, G. F., p. 51 Mishler, R., p. 55 Spielmann, J. A., pp. 45, 48 Connell, S. D., p. 49 Hunt, A. P., pp. 44, 52, 53, 54 Morgan, G. S., p. 43 Spilde, M. N., p. 42 Cox, D. M., p. 41 Hurlburt, G., p. 53 Morgan, V., p., 45 Voigt, S., p. 44 DiMichele, W. A., p. 43 Jeter, H. W., p. 46 Mozley, P. S., p. 48 Wilcox, L. J., p. 46 Downs, A., p. 53 Johnson, S. C., p. 44 Nagihara, S., p. 41 Wilde, G. L., p. 48 Elrick, M. B., p. 45 Kappus, E., p. 54 Nelson, J., p. 43 Williamson, T. E., p. 44 Evans, T., p. 51 Katcher, D. K., p. 50 Newton, B. T., p. 46 Wilson, D., p. 47 Farlow, J. O., p. 53 Koning, D. J., p. 49 Norman, D., p. 47 Wilson, J. E., p. 50 Gardner, J. N., pp. 47, 50 Krainer, K., pp. 45, 48, 52 Northup, D. E., p. 43 Wilson, J. L., p. 46 Gehrels, G., p. 49 Kyle, P. R., pp. 46, 47 Orchard, M. J., p. 52 Zeigler, K. E., pp. 44, 45, 52, 53, 54

NMGS abstracts subject index

Abo Formation, Bensing and Mozley, p. 48; Boston, and Northup, p. 42 Diamond Tail Formation, Porreca, p. 55 Krainer, Lucas, and Wilde, p. 48; Lerner, carbon dioxide, McLin, p. 51; McLin, Kyle, and Española Basin, Koning, p. 49 Lucas, and Voigt, p. 44 Norman, p. 47 Fruitland Formation, Hunt, Lucas, and archaeology Cerro de Cristo Rey, Kappus, Lucas, Heckert, Lockley, b, p. 53; Reser, Heckert, and Lucas, slip clays, Porreca, p. 55 and Hunt, p. 54 p. 54 temper material, Hardesty and Lindline, p. Chinle Group geochronology 55 Petrified Forest Formation, Heckert, Ar-Ar Bandelier Tuff Hurlburt, Farlow, and Zeigler, p. 53; southern Sangre de Cristo Mountains, fluid flow and transport, Wilson, Goodwin, Heckert, Zeigler, Lucas, Hunt, and Sanders and Heizler, p. 49 and Lewis, p. 50 Rinehart, p. 52; Lucas, Zeigler, Heckert, Valles caldera, Phillips, Goff, Kyle, Tshirege Member, Katcher, Lavine, Lewis, and Rinehart, p. 54 McIntosh, and Gardner, p. 46 Gardner, and Wilson, p. 50; Lavine, Lewis, Poleo Formation, Zeigler, Lucas, Spielmann, cesium-137 Katcher, Gardner, and Wilson, p. 50 and Morgan, p. 45 Mescalero Sands, Hall, Goble, and Jeter, p. Valles caldera, Phillips, Goff, Kyle, McIntosh, Salitral Formation, Zeigler, Lucas, Spielmann, 46 and Gardner, p. 46 and Morgan, p. 45 luminescence Bottomless Lakes State Park, Land, p. 41 Sloan Canyon Formation, Hunt, Lucas, and Mescalero Sands, Hall, Goble, and Jeter, p. Bull Canyon Formation, Hunt, Heckert, Lucas, Lockley, a, p. 53 46 and Zeigler, p. 44 Chuska Mountains, Spielmann, Lucas, and zircon U/Pb Burro Mountains, Amato, Sanders, and Braman, p. 48 Burro Mountains, Amato, Sanders, and Gehrels, p. 49 clay, Porreca, p. 55 Gehrels, p. 49 Bursum Formation, Harris and Lucas, p. 51; Cooke’s Range, Krainer, Lucas, and Wilde, p. geophysics Harris, Lucas, Orchard, and Krainer, p. 52; 48 heat flow Krainer, Lucas, and Wilde, p. 48; Lucas and Cutler Formation, Rinehart, Lucas, Heckert, Socorro seismogenic zone, Reiter, p. 47 Krainer, p. 45 Zeigler, Berman, and Henrici, p. 52; Zeigler, seismology Carlsbad Caverns National Park, Morgan, p. Lucas, Heckert, Henrici, and Berman, p. 52 LA RISTRA experiment, Wilson and Aster, 43; Nagihara, p. 41; Northup, p. 43; Spilde, Delaware Basin, Hill, p. 42 p. 47

56 NEW MEXICO GEOLOGY May 2003, Volume 25, Number 2 Socorro magma body, Love, Allen, Asmerom, p. 41 Mescalero Sands, Hall, Goble, and Jeter, p. 46 Chamberlin, and Haneberg, p. 50 Pleistocene-Holocene transition, Polyak, Socorro County Socorro seismogenic zone, Reiter, p. 47 Rasmussen, and Asmerom, p. 41 Arroyo de la Presilla, Lucas, DiMichele, geothermal energy paleontology Chaney, and Nelson, p. 43 Lightning Dock Known Geothermal ammonites, Sealey and Lucas, p. 54 Cerros de Amado, Lerner, Lucas, and Voigt, Resource Area, McLin, Kyle, and Norman, Canjilon Quarry, Heckert, Hurlburt, Farlow, p. 44 p. 47 and Zeigler, p. 53 soil, Evans and Lindline, p. 51; McLin, p. 51; ground water Cardillo Quarry, Zeigler, Lucas, Heckert, Spilde, Boston, and Northup, p. 42 chemical and microbial content, Schulze- Henrici, and Berman, p. 52 speleogenesis Makuch, p. 46 dinosaurs, Hunt, Heckert, Lucas, and Zeigler, Carlsbad Cavern, Nagihara, p. 41 ground water-Rio Grande interaction, p. 44; Reser, Heckert, and Lucas, p. 54; Faja de Oro atoll (El Abra reef), Cox, p. 41 Newton, Wilcox, and Bowman, p. 46; Williamson and Carr, p. 44 Hansonburg mining district, Lueth and Rye, Wilcox, Shafike, and Bowman, p. 46 Elephant Butte Reservoir, Williamson and p. 42 soil-bedrock interface, Guan and Wilson, p. Carr, p. 44 hydrofluoric acid speleogenesis, Lueth and 46 lycopsid flora, Lucas, DiMichele, Chaney, Rye, p. 42 Taos Valley, Benson and Atencio, p. 51 and Nelson, p. 43 hydromagnesite balloons, Provencio and Tularosa Basin, Huff, p. 51 mammals, Libed and Lucas, p. 44; Morgan, Polyak, p. 56 Harding County p. 43 iron- and manganese-oxidizing bacteria, Bravo Dome field, McLin, p. 51 nonmarine invertebrates, Lucas, Zeigler, Northup, p. 43 Hidalgo County Heckert, and Rinehart, p. 54; Rinehart, late Holocene, Rasmussen, Polyak, and Lightning Dock Known Geothermal Lucas, Heckert, Zeigler, Berman, and Asmerom, p. 41 Resource Area, McLin, Kyle, and Norman, Henrici, p. 52 Lechuguilla Cave, Northup, p. 43; Spilde, p. 47 palynomorphs, Spielmann, Lucas, and Boston, and Northup, p. 42 karst Braman, p. 48 Mission Tunnel, Santa Barbara, CA, Boles, p. mineral deposition, Hill, p. 42; Lueth and sharks, Johnson and Lucas, p. 44 42 Rye, p. 42; McLemore, p. 42 Slaughter Canyon Cave, Morgan, p. 43 North Franklin Mountains mining district, National Cave and Karst Research Institute, Snyder Quarry, Heckert, Hurlburt, Farlow, Lueth and Rye, p. 42 Hose, p. 55; Hose, Bailey, Land, and and Zeigler, p. 53; Heckert, Zeigler, Lucas, Pleistocene-Holocene transition, Polyak, Boston, p. 55 Hunt, and Rinehart, p. 52; Lucas, Zeigler, Rasmussen, and Asmerom, p. 41 Pecos River floodplain, Land, p. 41 Heckert, and Rinehart, p. 54 Spider Cave, Northup, p. 43; Spilde, Boston, sulfuric acid karst, Hill, p. 42 tracksites, Hunt, Lucas, and Lockley, a, p. 53; and Northup, p. 42 Los Alamos National Laboratory, Katcher, Hunt, Lucas, and Lockley, b, p. 53; Kappus, sulfuric acid speleogenesis, Lueth and Rye, p. Lavine, Lewis, Gardner, and Wilson, p. 50; Lucas, Heckert, and Hunt, p. 54; Lerner, 42 Lavine, Lewis, Katcher, Gardner, and Wilson, Lucas, and Voigt, p. 44 stratigraphy p. 50; Wilson, Goodwin, and Lewis, p. 50 vertebrates, Harris and Lucas, p. 51; Harris, Gray Mesa Member, Scott and Elrick, p. 45 Lucero uplift, Harris and Lucas, p. 51; Harris, Lucas, Orchard, and Krainer, p. 52; Upper Cretaceous, Spielmann, Lucas, and Lucas, Orchard, and Krainer, p. 52; Scott and Heckert, Hurlburt, Farlow, and Zeigler, p. Braman, p. 48 Elrick, p. 45 53; Hunt and Downs, p. 53; Zeigler, Lucas, structural geology Madera Group, Krainer, Lucas, and Wilde, p. Spielmann, and Morgan, p. 45 Colorado Plateau–Rio Grande rift–Great 48; Scott and Elrick, p. 45 Welles Quarry, Rinehart, Lucas, Heckert, Plains seismic transect, Wilson and Aster, Mancos Shale, Sealey and Lucas, p. 54 Zeigler, Berman, and Henrici, p. 52 p. 47 maps Pennsylvanian–Permian transition, Krainer, surface water geology of Albuquerque–Rio Rancho, Lucas, and Wilde, p. 48; Lucas and Krainer, p. chemical and microbial content, Schulze- Connell, p. 49 45 Makuch, p. 46 Landsat mapping of evaporite minerals, petroleum and natural gas Las Vegas National Wildlife Refuge (Melton Ghrefat and Goodell, p. 47 Bravo Dome field, McLin, p. 51 Pond), Evans and Lindline, p. 51 3-D topographic map of Carlsbad Cavern, Pictured Cliffs Sandstone, Johnson and Lucas, seepage losses, Evans and Lindline, p. 51; Nagihara, p. 41 p. 44 Newton, Wilcox, and Bowman, p. 46; McRae Formation, Williamson and Carr, p. 44 Rio Grande Wilcox, Shafike, and Bowman, p. 46 metasomatism, Sanders and Heizler, p. 49 seepage losses, Newton, Wilcox, and tectonics mining districts Bowman, p. 46; Wilcox, Shafike, and Socorro magma body, Love, Allen, Carlsbad potash district, McLemore, p. 42 Bowman, p. 46 Chamberlin, and Haneberg, p. 50 Grants uranium district, McLemore, p. 42 Sacramento Mountains, Schulze-Makuch, p. 46 Todilto Formation, Hunt and Downs, p. 53 Hansonburg district, Lueth and Rye, p. 42 San Juan Basin, Hunt, Lucas, and Lockley, b, p. Tohatchi Formation, Spielmann, Lucas, and Lake Lucero–Alkali Flat evaporite minerals, 53; Johnson and Lucas, p. 44; Libed and Braman, p. 48 Ghrefat and Goodell, p. 47 Lucas, p. 44; Reser, Heckert, and Lucas, p. 54 Tularosa Basin, Huff, p. 51 North Franklin Mountains district, Lueth Sandia Formation, Lucas, DiMichele, Chaney, Union County and Rye, p. 42 and Nelson, p. 43 Bravo Dome field, McLin, p. 51 Mojado Formation, Kappus, Lucas, Heckert, Sangre de Cristo Mountains, Sanders and Valles caldera, Phillips, Goff, Kyle, McIntosh, and Hunt, p. 54 Heizler, p. 49 and Gardner, p. 46 Orogrande Basin, Krainer, Lucas, and Wilde, p. Santa Fe Group, Koning, p. 49 Valles Rhyolite, Phillips, Goff, Kyle, McIntosh, 48 sedimentology and Gardner, p. 46 paleoenvironments Los Medaños dune field, Mahoney, p. 48 late Holocene, Rasmussen, Polyak, and

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