Sandoval County Research Articles

Fossil fishes from a lag deposit within the Upper Cretaceous Mancos Shale in New Mexico, USA, with comments on correlative Turonian–Coniacian time-transgressive lags in the Western Interior Seaway of North America

A lag deposit between the Tocito Sandstone and Mulatto Tongue of the Upper Cretaceous Mancos Shale in Sandoval County, New Mexico, USA, contains a fossil assemblage of late Turonian–early Coniacian chondrichthyans and osteichthyans. This assemblage consists primarily of isolated teeth that derive from at least 26 taxa including: Meristodonoides sp.; Ptychodus mortoni; P. mammillaris; Scapanorhyncus raphiodon; Protolamna sp.; Cretodus cf. C. semiplicatus; Cretodus sp.; Cretalamna “appendiculata”; cf. Eostriatolamia tenuiplicatus; Archaeolamna cf. A. kopingensis; Squalicorax cf. S. falcatus; S. deckeri; Squalicorax sp.; Paranomotodon(?) sp.; Rhinobatos lobatus; Ptychotrygon triangularis; Texatrygon hooveri; Pseudohypolophus mcnultyi; Ischyrhiza mira; Chondrichthyes indet.; Micropycnodon cf. M. kansasensis; Pycnodontiformes indet.; Aspidorhynchidae indet.; Protosphyraena sp.; and Enchodus cf. E. gladiolus. The lag deposit formed along a series of outer shoreface and discontinuous sandbars in the southeastern corner of the San Juan Basin during eustatic sea-level fluctuation herein referred to as the Turonian–Coniacian Time Transgressive (TCTT) Event. This sea-level event and the concentration of fish remains into a lag deposit is also recorded at several other states within the Western Interior Seaway of North America. These stratigraphic properties have correlative potential across basins and states and provide a framework by which regional and eustatic sea-level events can be interpreted. Differences in coeval faunas found within these TCTT lags are bathymetrically controlled, related to the degree of taphonomic reworking, and proximity of the ancestral shoreline.

Copper-Mineralized Fossil Wood from the Nacimiento Mining District, Sandoval County, New Mexico

ANYONE INTERESTED IN MINERALS OR LAPIDARY PURSUITS is likely familiar with petrified wood. It is formed when minerals replace the structure of formerly living plant material but keep the original p...

Discovery of the Yellow-Bellied Marmot (Marmota flaviventris) in the Jemez Mountains, New Mexico: Examining Competing Hypotheses for Range Extension

The yellow-bellied marmot (Marmota flaviventris) reaches the southern edge of its geographic range in New Mexico, where it is known from the San Juan and Sangre de Cristo Mountains. We provide a synopsis of the geographic range of M. flaviventris in New Mexico and report 5 recent records from the Jemez Mountains, Los Alamos and Sandoval Counties. Of the 5 records from the Jemez Mountains, 3 were obtained at high-elevation sites (>2690 m) during routine fieldwork and while conducting surveys for the American pika (Ochotona princeps), and 2 were from a residential area at relatively low elevation (2204 m) on a finger-mesa in Los Alamos. We evaluate 3 hypotheses for the provenance of the new records and conclude that M. flaviventris has maintained a relictual occurrence in the Jemez Mountains, but that the recent detections were due to (1) increased mammalogy fieldwork at high elevations, digital camera technology, and social media that allowed mammalogists to become aware of observations, and (2) possibly altered behavior by marmots due to impacts of recent widespread wildfire. Because small, isolated populations of marmots are vulnerable to extinction, research is needed to assess the status and trend of marmots in the Jemez Mountains, as well as in adjacent mountain ranges in New Mexico, with emphasis on identifying conservation threats and prospects for long-term persistence in the state.

Lower Jaw of Spathites (Ammonoidea: Acanthoceratoidea) from the Upper Cretaceous (Turonian) of New Mexico

A lower jaw was recently discovered in a limestone concretion in association with the Late Cretaceous (Turonian) ammonite Spathites puercoensis (Herrick and Johnson, 1900) from the Carlile Member of the Mancos Shale in Sandoval County, New Mexico. It is nearly complete and comprises the aptychus with a hinge along the midline. The better-preserved plate, the left (according to its position in life), is roughly triangular in shape with a broadly rounded lateral margin, a narrowly rounded posterior margin, and a weakly concave anterior margin. It is 26.2 mm wide and 33.0 mm long. Together, the left and right plates form an escutcheonlike shape that projects slightly forward at the apex. The ratio of jaw width to length (26.2 mm × 2 / 33.0 mm) equals 1.59. The aptychus consists of yellow-orange calcite and is covered with comarginal ribs that parallel the lateral and posterior margins and become more prominent toward the posterior end. It is likely that this jaw belongs to the associated ammonite and would have comfortably fit inside the body chamber, based on a comparison of the length of the jaw and the whorl height, suggesting that it functioned as a jaw, rather than as an operculum. It is the first report of an ammonite jaw in the genus Spathites and the first reported occurrence of an ammonite jaw from New Mexico.

The Upper Jurassic Morrison Formation in north-central New Mexico–Linking Colorado Plateau stratigraphy to the stratigraphy of the High Plains

Most study of the Upper Jurassic Morrison Formation has focused on its spectacular and extensive outcrops on the southern Colorado Plateau. Nevertheless, outcrops of the Morrison Formation extend far off the Colorado Plateau, onto the southern High Plains as far east as western Oklahoma. Outcrops of the Morrison Formation east of and along the eastern flank of the Rio Grande rift in north-central New Mexico (Sandoval, Bernalillo, and San­ta Fe Counties) are geographically intermediate between the Morrison Formation outcrops on the southeastern Colorado Plateau in northwestern New Mexico and on the southern High Plains of eastern New Mexico. Previous lithostratigraphic correlations between the Colorado Plateau and High Plains Morrison Formation outcrops using the north-central New Mexico sections encompassed a geographic gap in outcrop data of about 100 km. New data on previously unstudied Morrison Formation outcrops at Placitas in Sandoval County and south of Lamy in Santa Fe County reduce that gap and significantly add to stratigraphic coverage. At Placitas, the Morrison Formation is about 141 m thick, in the Lamy area it is about 232 m thick, and, at both locations, it consists of the (ascending) sandstone-dominated Salt Wash Member, mudstone-dominated Brushy Basin Member, and sandstone-dominat­ed Jackpile Member. Correlation of Morrison strata across northern New Mexico documents the continuity of the Morrison depositional systems from the Colorado Plateau eastward onto the southern High Plains. Along this transect, there is significant stratigraphic relief on the base of the Salt Wash Member (J-5 unconformity), the base of the Jackpile Member, and the base of the Cretaceous strata that overlie the Morrison Formation (K unconfor­mity). Salt Wash Member deposition was generally by easterly-flowing rivers, and this river system continued well east of the Colorado Plateau. The continuity of the Brushy Basin Member, and its characteristic zeolite-rich clay facies, onto the High Plains suggests that localized depositional models (e.g., “Lake T’oo’dichi’) need to be re-eval­uated. Instead, envisioning Brushy Basin Member deposition on a vast muddy floodplain, with some localized lacustrine and palustrine depocenters, better interprets its distribution and facies.

The Upper Jurassic Morrison Formation in north-central New Mexico–Linking Colorado Plateau stratigraphy to the stratigraphy of the High Plains

Most study of the Upper Jurassic Morrison Formation has focused on its spectacular and extensive outcrops on the southern Colorado Plateau. Nevertheless, outcrops of the Morrison Formation extend far off the Colorado Plateau, onto the southern High Plains as far east as western Oklahoma. Outcrops of the Morrison Formation east of and along the eastern flank of the Rio Grande rift in north-central New Mexico (Sandoval, Bernalillo, and San­ta Fe Counties) are geographically intermediate between the Morrison Formation outcrops on the southeastern Colorado Plateau in northwestern New Mexico and on the southern High Plains of eastern New Mexico. Previous lithostratigraphic correlations between the Colorado Plateau and High Plains Morrison Formation outcrops using the north-central New Mexico sections encompassed a geographic gap in outcrop data of about 100 km. New data on previously unstudied Morrison Formation outcrops at Placitas in Sandoval County and south of Lamy in Santa Fe County reduce that gap and significantly add to stratigraphic coverage. At Placitas, the Morrison Formation is about 141 m thick, in the Lamy area it is about 232 m thick, and, at both locations, it consists of the (ascending) sandstone-dominated Salt Wash Member, mudstone-dominated Brushy Basin Member, and sandstone-dominat­ed Jackpile Member. Correlation of Morrison strata across northern New Mexico documents the continuity of the Morrison depositional systems from the Colorado Plateau eastward onto the southern High Plains. Along this transect, there is significant stratigraphic relief on the base of the Salt Wash Member (J-5 unconformity), the base of the Jackpile Member, and the base of the Cretaceous strata that overlie the Morrison Formation (K unconfor­mity). Salt Wash Member deposition was generally by easterly-flowing rivers, and this river system continued well east of the Colorado Plateau. The continuity of the Brushy Basin Member, and its characteristic zeolite-rich clay facies, onto the High Plains suggests that localized depositional models (e.g., “Lake T’oo’dichi’) need to be re-eval­uated. Instead, envisioning Brushy Basin Member deposition on a vast muddy floodplain, with some localized lacustrine and palustrine depocenters, better interprets its distribution and facies.

Delivering Environmental Justice through Environmental Impact Assessment in the United States: The Challenge of Public Participation

The United States (US) occupies the frontline of events in modern history of environmental reform. The federal government through the National Environmental Policy Act (NEPA) of 1970 has not only established an environmental policy template for other nations to emulate, but has also produced a viable tool for regulating environmental quality (EQ) and delivering environmental justice (EJ)—Environmental Impact Assessment (EIA). However, environmental history provides evidence that political process and special interests govern the attainment of the EJ goal by way of inadequate adherence to the NEPA provisions. Public participation (PP) is a principal requirement for achieving EJ and constitutes a pivotal determinant of EIA outcome. Effective delivery of EJ through EIA does require complete compliance with NEPA stipulations. Furthermore, the responsible agency’s resources in terms of both funding and commitment in allowing for the full representation of the opinions of residents within communities of concern (CoC) for environmental decision-making process are critically important. Public health research approach offers valuable tools towards achieving EJ goals. To approach this topic, first I provide a historical background on EIA and EJ from the standpoint of the NEPA. Second, I discuss the meaning and impediments of PP. Third, I examine two scenarios viz the Triassic Park Hazardous Waste Dump in Roswell, and the public hearing of the recent “controversial” oil and gas ordinance in Sandoval County, both in New Mexico. Finally, in the discussion part, I attempt to evaluate PP in both cases and suggest that none of the criteria seem to have been met in either case. I conclude that the Home State Rule designation of New Mexico State in terms of control over oil and gas activities places it at an advantage in benefitting from a fair PP.

An Innovative Longitudinal Educational Approach to Maternal‐Child Community Health

Poster Presentation Purpose for the Program The health care environment is rapidly changing. Nurse educators must develop innovative curricula to prepare future nurses to respond to the community maternal/child health needs of an evolving health care system. Proposed Change Starting in 2012, University of New Mexico (UNM) graduate and undergraduate faculty partnered to provide bachelor of science in nursing (BSN) students with a longitudinal community clinical experience through the Family Health Partnership (FHP). The FHP, a faculty practice located in rural Sandoval County, NM, is a federally funded, nurse‐managed practice center. Using the FHP as a clinical site, a three‐term sequence of community‐based maternal/child electives were developed to engage students in activities aimed at promoting maternal/child health, preventing disease, decreasing health care disparities, and increasing access to care. Implementation, Outcomes, and Evaluation BSN students worked with certified nurse–midwives, nurse practitioners, community health workers, and a mental health nurse practitioner to provide group prenatal care, well‐child group care, and labor support; perform extended family assessments; and research community resources. Student reported benefits included building connection to a community, increased understanding of the benefits of the provision of preventative services in the community, and an increased interest in working in maternal/child community settings and/or graduate nurse midwifery programs after graduation. Implications for Nursing Practice Partnerships between graduate and undergraduate nursing faculty and utilization of faculty practice sites can provide opportunities to provide longitudinal, innovative, clinical experiences for BSN students that increase interest in maternal–child health and community health.

Suburban Growth in the Atomic West

One company—Sandia Laboratories—transformed the economic geography, demographics, and future of postwar Albuquerque. Sandia’s construction and expansion during and after World War II drew thousands of educated newcomers to town while creating an instant housing shortage. After 1950, the growing presence of Sandia, nearby Kirtland Air Force Base, and the huge technological complex that emerged on the desolate foothills of the Sandia Mountains thrust Albuquerque northeastward in a new direction. Over time, this wave of suburbanization set the precedent for a northward building trend that, by the 1970s, would spill northwestward from Bernalillo into neighboring Sandoval County. It all began with Sandia. The so-called “science suburbs” of the 1950s and 1960s gradually filled the Northeast Heights with a new population of white-collar, upper-middle-class families and individuals that made Albuquerque a dynamic, modern city characterized by scientific research, higher education, and a strong federal presence. Local boosters used the introduction of the Lab to portray Duke City as a diverse metropolis, welcoming industry and growth. “Duke City” is a nickname for Albuquerque that hearkens to the Spanish Duke of Alburquerque for whom the town was named. The first “r” in Alburquerque was eventually dropped from the city’s name.

Lithostratigraphy, Paleontology, Biostratigraphy, and Age of the Upper Paleozoic Abo Formation Near Jemez Springs, Northern New Mexico, USA

In the Jemez Springs area of Sandoval County, northern New Mexico, siliciclastic red beds of the upper Paleozoic Abo Formation are well exposed and yield fossil plants and vertebrates. The local Abo Formation section is more than 190 m thick and rests disconformably on the Upper Pennsylvanian Guadalupe Box Formation and is conformably overlain by the Lower Permian DeChelly Sandstone (Yeso Group). Abo sandstone sheets are low sinuosity river deposits, and intercalated sandstone beds and lenses represent sheet splays and minor channel fills that formed during overbank flooding. The dominant Abo lithofacies is mudstone, which represents floodplain deposits, many with calcareous paleosols. Fossils are present in three stratigraphie intervals of the lower to middle Abo Formation. All three intervals yield eupelycosaur-dominated vertebrate fossil assemblages of Coyotean age (Coyotean = late Virgilian-Wolfcampian on the North American provincial marine timescale: Lucas 2006). The lowest interval also yields the Spanish Queen Mine paleoflora of pteridosperms and conifers. Strata of the Guadalupe Box Formation disconformably below the Abo Formation contain late Virgilian fusulinids. We correlate the Abo Formation fossil assemblages in the Jemez Springs area to the Coyotean-age fossil assemblages in the upper part of the El Cobre Canyon Formation in the Arroyo del Agua area and in the Canon del Cobre in the Chama basin of northern New Mexico. This suggests a middle Wolfcampian age for the Jemez Springs area fossil assemblages, an age very close to the Pennsylvanian-Permian boundary.

Shrew Flea,Corrodopsylla curvata1, in Nest and Range Extension in New Mexico with Review of Relevant Records in Six Western States

The shrew flea, Corrodopsylla curvata curvata (Rothschild, 1915) (Siphonaptera: Ctenophthalmidae), is not common in collections of fleas from the Southwest or Rocky Mountains. Fewer records are from nests than trapped hosts. In 1993, a live female specimen was found in a nest that belonged to an unknown small mammal in the southern Sangre de Cristo Mountains of New Mexico. A 67km extension of range was measured from the nearest of four trap sites in the Jemez Mountains, Sandoval County. The nest site was east-southeast across the Rio Grande in Dalton Canyon, Pecos River watershed, San Miguel County. The nest, its contents, and habitat were described. In addition, we reviewed nonpublished ecological data from each of the three collections from trapped hosts in the Jemez Mountains, 1970–1971, and provided a distribution map. A review of records of C. c. curvata and C. c. obtusata (Wagner, 1929) in western mountains with emphasis on small samples from a canyon in Montana suggested that larger samples would confirm the absence of a zone of intergradation between two allopatric species.

The Aquatic Insects of the Valles Caldera National Preserve, Sandoval County, New Mexico, Excluding Diptera, with Notes on New State Records

Aquatic insects were collected on the Valles Caldera National Preserve (VCNP), in Sandoval County, New Mexico in 2003 and 2004. We surveyed running water and standing water habitats for Ephemeroptera, Odonata, Plecoptera, Hemiptera, Trichoptera, and Coleoptera. In general, species were typical southern Rocky Mountain and southwestern fauna. A total of 130 species was collected, representing 46 families and 90 genera; 14 of these species were new state records. Trichoptera was the most diverse order and seven species represented new state records, including Agraylea multipuctata Curtis, Hydroptila xera Ross, Ochrotrichia logana (Ross), Psychoglypha subborealis (Banks), Polycentropus gertschi Denning, and new species of Neotrichia Morton and Helicopsyche von Siebold. Collections of the mayfly species Cinygmula ramaleyi (Dodds) and Paraleptophlebia temporalis (McDunnough) represented new state records. The aquatic beetles Haliplus immaculicollis Harris, H. leechi Wallis, and Ametor scabrosus Horn and the hemipterans Callicorixa audeni Hungerford and Gerris gillettei Lethierry and Severin, also represented new state records. Small creeks fed by spring runs were the most diverse aquatic systems on the VCNP.

THERE IS NO VALID RECORD OF CLIFF CHIPMUNK (TAMIAS DORSALIS) IN THE SANDIA MOUNTAINS, NEW MEXICO

A report of the cliff chipmunk (Tamias dorsalis) from the Sandia Mountains, New Mexico, was erroneous. The capture location of the specimen was actually the Rio Puerco drainage in Sandoval County. There are no records of the cliff chipmunk from the Sandia Mountains or elsewhere east of the Rio Grande.

America's Struggle for Same-Sex Marriage. By Daniel R. Pinello. New York: Cambridge University Press, 2006. Pp. xiii+213. $55.00 cloth; $19.99 paper.

America's Struggle for Same-Sex Marriage. By Daniel R. Pinello. New York: Cambridge University Press, 2006. Pp. xiii+213. $55.00 cloth; $19.99 paper. Reviewed by Kathleen E. Hull, University of Minnesota The Massachusetts Supreme Judicial Court's ruling in Goodridge v. Department of Public Health in November 2003, finding right to marriage for same-sex couples, triggered chain of highly visible and dramatic developments in marriage law and politics. In early 2004, after hearing President George W. Bush vow to protect the sanctity of marriage in his State of the Union address, newly elected San Francisco mayor Gavin Newsom took the bold step of having his city hall issue marriage licenses to same-sex couples. Local authorities in several jurisdictions around the country-including Sandoval County in New Mexico, Multnomah County in Oregon, and tiny New Paltz, New York-quickly followed suit. These marriages were eventually voided by courts, but they further dramatized the rights claims of same-sex couples. In May 2004, Massachusetts began issuing marriage licenses to same-sex couples residing in the state, and it remains the only state with legal samesex marriage. In reaction, 13 states passed constitutional amendments banning same-sex marriage in late 2004, and some political analysts concluded that these amendments helped galvanize social conservative voters and secure President Bush's re-election. Since the 2004 elections, three more state supreme courts have ruled on same-sex marriage rights, with two rejecting such claims (New York and Washington) and one finding right to the legal equivalent of marriage (New Jersey). With court cases and amendment battles pending in several other states, the end of the story of legal same-sex marriage in the United States remains unwritten. Daniel Pinello's book America's Struggle for Same-Sex Marriage provides carefully researched and clearly written account of the legal and political events catalyzed by the Goodridge ruling. Using information from 85 in-depth interviews with activists, government officials, and ordinary same-sex couples, Pinello paints detailed portraits of how the marriage battles unfolded in various locales. The book begins with the somewhat quirky case of Sandoval County, New Mexico, where renegade Republican county clerk issued 64 marriage licenses in one day, and later chapters document more extensively the conflicts in Massachusetts, California, Oregon, and New York. Pinello asserts that his case studies represent a microcosm of the American legal and political universe (p. 30), raising broader questions about the role and impact of courts in democratic society, the influence of interest groups, and the interplay of policy initiative and political process. Pinello argues that Goodridge and the ensuing events will prove highly significant in historical terms, and he expresses confidence (as same-sex marriage supporter) that the long-term progress set in motion by Goodridge will ultimately outweigh the short-term backlash it so obviously provoked. This book has considerable strengths, including access to key players in same-sex marriage contests at the local and national levels, writing style that is relatively free of social science jargon, and willingness to let informants speak for themselves at some length, which sometimes produces fascinating nuggets of information and insight. Some of the more striking observations come from people involved in the month-long Winter of Love in February-March 2004, when San Francisco City Hall issued marriage licenses to more than 4,000 same-sex couples. …

Late Pleistocene (Rancholabrean) mammals from fissure deposits in the Jurassic Todilto Formation, White Mesa mine, Sandoval County, north-central New Mexico

Late Pleistocene (Rancholabrean) mammals from fissure deposits in the Jurassic Todilto Formation, White Mesa mine, Sandoval County, north-central New Mexico

Potential environmental impact of the abandoned La Bajada uranium mine near Cochiti Lake, Santa Fe and Sandoval Counties, New Mexico

Potential environmental impact of the abandoned La Bajada uranium mine near Cochiti Lake, Santa Fe and Sandoval Counties, New Mexico

A NEW COCCIDIAN (APICOMPLEXA: EIMERIIDAE) IN THE NORTHERN POCKET GOPHER (THOMOMYS TALPOIDES) AND A COMPARISON OF OOCYST SURVIVAL IN HOSTS FROM RADON-RICH AND RADON-POOR SOILS

Forty (93%) of 43 northern pocket gophers (Thomomys talpoides) from the Jemez Mountains, Sandoval County, New Mexico (USA), had coccidian oocysts in their feces when examined. We describe this parasite, Eimeria jemezi, n. sp. Sporulated oocysts were subspheroidal, 13.3 by 12.2 (10 to 17 by 9 to 15) microns, with sporocysts ellipsoidal, 7.1 by 4.4 (5 to 9 by 4 to 5) microns; micropyle and oocyst residuum were absent, but polar bodies, Stieda bodies and sporocyst residua were present. All gophers were collected from two sites of similar habitat 7 km apart. One site (R+) had a high soil radon content (> or = 50 to 70 picocuries (pCi) per liter of air) whereas the other site (R-) had soils that were near average natural levels (1.2 to 1.6 pCi/g uranium nucleotides per gram of soil; < 1.9 pCi/g thorium nucleotides). Twenty-one (88%) of 24 gophers from the R+ site had coccidian oocysts in their intestines when examined, but none of these oocysts ever sporulated, whereas all 19 (100%) gophers from the R- site had coccidian oocysts in their intestines and 16 (84%) of these samples sporulated normally under laboratory conditions. The elevated radon content of the soil may have had an adverse effect on the sporulation of this coccidian while it still was intracellular within its host.

Geology and stratigraphy of the Seismosaurus locality, Sandoval County, New Mexico

Geology and stratigraphy of the Seismosaurus locality, Sandoval County, New Mexico

Stratigraphy and Vertebrate Biostratigraphy of Lower Eocene Regina Member, San Jose Formation, Sandoval County, San Juan Basin, New Mexico: ABSTRACT

The Regina Member of the San Jose Formation is a nonmarine fluvial deposit well known as a source of early Eocene (Wasatchian) fossil vertebrates. It is particularly well exposed along the Continental Divide south of Canada Largo on the Jicarilla Apache Indian Reservation in Sandoval County. Seventeen sections were measured in an area encompassed by Secs. 2 and 3 of T21N, R3W; Secs. 3, 10, 15, 16, 17, 21, and 28 of T22N, R2W; and Secs. 27, 34, 35, and 36 of T23N, R2W. In this area, the Regina Member is approximately 80 m thick, overlies the Cuba Mesa Member of the San Jose Formation, and is overlain by the Llaves Member of the San Jose Formation. It consists of about 40% sandstone, 30% siltstone, and 30% mudstone. Typical lithologies are yellowish gray (5 Y 8/1) subarkosic sandstone that is poorly sorted, trough-cross-bedded, well indurated, and calcareous; greenish gray (5 GY 5/2), grayish red (5 R 4/2), and yellowish gray (5 Y 8/1) variegated siltstone; and light olive (10 Y 4/2), pale yellowish brown (10 YR 5/4) and very dusky red-purpose (5 RP 2/2) variegated mudstone. Through extensive surface prospecting in this area, 1,192 specimens of fossil vertebrates from 211more » localities have been recovered. Fossils tend to occur in variegated mudstones and siltstones and are often associated with carbonate concretions. Fossils are confined to three relatively narrow zones: (1) about 70 to 75 m below the base of the Llaves Member; (2) about 40 to 50 m below the base of the Llaves Member; and (3) about 18 to 25 m below the base of the Llaves Member. The mammalian fauna from all three of these zones suggest a middle Wasatchian (Lysitean) age.« less

Potential for Economic Coal Development in Upper Coal Member of Menefee Formation, Torreon Wash Area, Sandoval County, New Mexico: ABSTRACT

In the southeastern part of the San Juan basin, the transgressive La Ventana member of the Cliff House Sandstone represents a near-vertical buildup of barrier-beach sands during a period when sediment supply was in approximate balance with subsidence and shore-marginal environments migrated landward/seaward over a limited horizontal distance. Recognition of these conditions leads to speculation regarding a corresponding back-barrier accumulation of coal-bearing strata. Using logs from both the project-sponsored drill holes and commercial oil and gas tests, the workers have compiled an 8.5-mi stratigraphic cross section oriented normal to the depositional strike. This cross section illustrates the laterally changing relationships between the La Ventana and the upper Menefee. At the north (seaward) end, the interval is principally sandstone with thin tongues of coal-bearing shale and siltstone. Southward the barrier beach sand units split, thin, and give way to increasing numbers of coal-bearing intervals. Five major La Ventana sandstone tongues and a corresponding number of upper Menefee tongues alternate through an interval of about 650 ft. The number of individual coal beds ranges from 3 to 18, and thicknesses range from about 1 to 8 ft.