Geology of the Chama Basin最新文献

{"title":"Lithofacies of the Pennsylvanian Osha Canyon Formation at the type section, Jemez Mountains, New Mexico","authors":"K. Krainer, S. Lucas","doi":"10.56577/ffc-56.139","DOIUrl":"https://doi.org/10.56577/ffc-56.139","url":null,"abstract":"A BSTRACT .— The Pennsylvanian Osha Canyon Formation at the type section in the Jemez Mountains (northern New Mexico) is a 27.3-m thick succession composed of fossiliferous marly shale with intercalated limestone beds and a mixed siliciclastic-carbonate sandstone bed on top. Limestone is represented by bioclastic grainstone, locally grading into packstone. The mixed siliciclastic-carbonate sandstone forming the uppermost part of the section contains up to 20% skeletal grains. Sediments of the Osha Canyon Formation were deposited in a shallow-marine shelf environment with","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121700163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mesozoic stratigraphy at Durango, Colorado","authors":"A. Heckert","doi":"10.56577/ffc-56.160","DOIUrl":"https://doi.org/10.56577/ffc-56.160","url":null,"abstract":"A nearly 3-km-thick section of Mesozoic sedimentary rocks is exposed at Durango, Colorado. This section consists of Upper Triassic, Middle-Upper Jurassic and Cretaceous strata that well record the geological history of southwestern Colorado during much of the Mesozoic. At Durango, Upper Triassic strata of the Chinle Group are ~ 300 m of red beds \u0000deposited in mostly fluvial paleoenvironments. Overlying Middle-Upper Jurassic strata of the San Rafael Group are ~ 300 m thick and consist of eolian sandstone, salina limestone and siltstone/sandstone deposited on an arid coastal plain. The Upper Jurassic Morrison Formation is ~ 187 m thick and consists of sandstone and mudstone deposited in fluvial environments. The \u0000only Lower Cretaceous strata at Durango are fluvial sandstone and conglomerate of the Burro Canyon Formation. Most of the overlying Upper Cretaceous section (Dakota, Mancos, Mesaverde, Lewis, Fruitland and Kirtland units) represents deposition in and along the western margin of the Western Interior seaway during Cenomanian-Campanian time. Volcaniclastic strata of the overlying McDermott Formation are the youngest Mesozoic strata at Durango.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116018874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonmarine bivalves from the Lower Permian (Wolfcampian) of the Chama Basin, New Mexico","authors":"S. Lucas, L. Rinehart, G. Spencer","doi":"10.56577/ffc-56.283","DOIUrl":"https://doi.org/10.56577/ffc-56.283","url":null,"abstract":"—The Welles quarry is an Early Permian (Wolfcampian) vertebrate fossil locality developed in a pond deposit in the El Cobre Canyon Formation of the Cutler Group near Arroyo del Agua, Rio Arriba County, New Mexico. We describe an extensive assemblage of thin-shelled, freshwater bivalves from the quarry preserved as external and (rarely) internal casts. Typical preservation is with the paired valves wide open (~180o), the hinge intact, and exterior surfaces facing upward. The clams are equivalved, inequilateral, and elongate oval in shape. Ligaments are external and opistodetic, hinges are straight and edentate, and adductor muscle scars are absent or not preserved. Length ranges from ~ 1 to ~ 23 mm. Umbones are slightly inflated and located at ~ 0.25 of length from the anterior end. Ornamentation consists only of concentric growth ridges. Two variants, one with a rounded posterior end, and the other more blunt, may represent sexual dimorphs. Allometric height-tolength ratio (≈ 0.45) and overall morphology are essentially identical to the Late Permian anthracosiid Palaeanodonta parallela (Amalitzky), known from South Africa and Russia. However, due to the large temporal and geographic range differences between P. parallela and the Welles quarry specimens, we provisionally assign them to P. cf. P. parallela. This is the first report of Palaeanodonta from the Permian of North America, a substantial extension of its stratigraphic range from the Middle Permian to nearly the base of the Permian and suggests that too little is known of late Paleozoic nonmarine bivalves for them to be of great biostratigraphic utility.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116637019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gravity and flexure models of the San Luis, Albuquerque, and Tularosa basins in the Rio Grande rift, New Mexico, and southern Colorado","authors":"C. Peterson, M. Roy","doi":"10.56577/ffc-56.105","DOIUrl":"https://doi.org/10.56577/ffc-56.105","url":null,"abstract":"—The Rio Grande rift is a Cenozoic continental rift zone that trends south from central Colorado through New Mexico and merges with a broader extensional zone in west Texas and Chihuahua, Mexico. The net upper crustal extension increases southward along the rift, accompanied by a southward-widening of the rift from a narrow zone encompassing a single basin in the north to a wide zone of multiple, laterally adjacent basins to the south. In this study we model the isostatic responses of the lithosphere to extension along the Rio Grande rift, and compare and contrast this response in the San Luis and Albuquerque basins in the narrow part of rift and the Tularosa basin in the wider region of the rift. Our flexural isostatic models are based on a joint-inversion of gravity and deflection data along the footwalls of major basin-bounding faults. The main difficulty in constraining isostatic response to extension in the Rio Grande rift is a lack of constraints on footwall deflection. Our approach is to use topography as a proxy for flexural deflection, and then to compare the estimated end-loads required for plate flexure in the footwall with the end-loads estimated from hanging wall and basin geometry. Using this approach we determine the extent to which flexural isostasy could have generated elevated rift-flanks, and how this process might change along strike. Our results indicate that flexural responses to extension are consistent with rock and surface uplift in the footwalls of the Albuquerque and the Tularosa basins in the central and southern Rio Grande rift. In the San Luis basin, however, although a flexural curve may adequately fit footwall topography, the plate-end loads required for flexure are inconsistent with those inferred from the hanging wall and basin geometries. Additionally, flexure-based estimates of crustal extension agree with geologic estimates in the Albuquerque and Tularosa basins, but not in the San Luis basin. We infer therefore, that rift-flank uplift due to flexure is likely only in the central and southern parts of the Rio Grande rift; to the north, we infer an additional (perhaps pre-rift) contribution to rift-flank topography.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124758052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface and subsurface stratigraphy of the Burro Canyon Formation, Dakota Sandstone, and intertongued Mancos Shale of the Chama Basin, New Mexico","authors":"Donald E. Owen, Angelique M. Forgas, Shawn A. Miller, Ryan J. Stelly, J. Owen","doi":"10.56577/ffc-56.218","DOIUrl":"https://doi.org/10.56577/ffc-56.218","url":null,"abstract":"—The Burro Canyon Formation (Lower Cretaceous) and the Dakota Sandstone (Upper Cretaceous: Cenomanian), including two tongues of the Mancos Shale, are present throughout the Chama Basin. The Dakota-Mancos section is divided into 7 marine members in the Chama Basin. The entire stratigraphic section thins southward across the Chama Basin, most notably the Clay Mesa Shale Tongue of the Mancos and the Paguate Sandstone of the Dakota. Prominent sequence-bounding unconformities, K1 and K2, bound the Burro Canyon Formation. A correlative conformity equivalent to the K3 sequencebounding unconformity occurs at the base of the Cubero Sandstone Tongue of the Dakota. A possible sequence boundary occurs at the base of the marine La Jollas bed, a local sandstone lens at the stratigraphic position of the upper Twowells Sandstone Tongue of the Dakota in the southern Chama Basin. FIGURE 1. Index map of the Chama Basin with location of cross-sections (Figs. 3, 4, and 5). The Tierra Amarilla Grant is not surveyed into townships and ranges. 219 STRATIGRAPHY OF THE BURRO CANYON FORMATION miscorrelation was corrected in Owen (2001, p. 32). Ridgley (1987) correlated the Burro Canyon Formation and units within the Dakota Sandstone in a series of uranium drill-hole logs to two measured sections near Heron Dam. She recognized the unconformities at the base and top of the Burro Canyon and divided the Dakota into informal units A (=Encinal Canyon Member), B (=Oak Canyon Member and Cubero Sandstone Tongue), and C (=Clay Mesa Shale Tongue of Mancos and Paguate Sandstone Tongue of Dakota). Varney (2001) proposed three sequences in the Dakota Sandstone at the Heron Dam section. Details are included in Varney (2005, this guidebook).","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"124 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116696533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The geological and geoarchaeological significance of Cerro Pedernal, Rio Arriba County, New Mexico","authors":"Gary A. Smith, B. Huckell","doi":"10.56577/ffc-56.425","DOIUrl":"https://doi.org/10.56577/ffc-56.425","url":null,"abstract":"—Cerro Pedernal is an isolated basalt-capped peak of substantial geologic and geoarchaeological significance. The peak is located on the Colorado Plateau near the boundary of the Rio Grande rift. Oligocene-Miocene stratigraphic units on Cerro Pedernal correlate to thicker sections within the rift and document initiation of rift-basin subsidence before 25 Ma. Cessation or near cessation of sedimentation on the nascent rift margin led to hypothesized extensive weathering and formation of pedogenic calcrete horizons that were later buried by volcaniclastic deposits that overlapped the rift margin. Diagenesis of vitric volcaniclastic detritus likely led to silica replacement of the calcareous soils to form the Pedernal chert, which was commonly used for lithic-tool manufacture for more than 13 millennia of human occupation in northern New Mexico. Heavily utilized chert quarries in the Cerro Pedernal-San Pedro Parks region were important lithic-material sources, but so were redeposited cobbles of chert that are ubiquitous in alluvial deposits on the Colorado Plateau and in the Rio Grande rift. The combination of primary and secondary chert sources has confounded efforts to determine the exact source locations of artifact raw materials. Fire, along with simple prying tools and hammerstones were likely used to dislodge large chert pieces for tool manufacture. Preliminary working of cores and bifaces produced large volumes of irregular flakes and rejected pieces that were mistaken by some early workers as finished products of more ancient tool-making cultures. FIGURE 1. View of Cerro Pedernal from the north. Miocene basalt caps a pinnacle of poorly exposed lower and middle Tertiary strata that rise above a base of Mesozoic rocks. Photo courtesy of Lisa W.Huckell. 426 SMITH AND HUCKELL Basalt flows and the intrusion of contemporary dikes along faults; they proposed that principal rift-basin subsidence in the Abiquiu embayment initiated at about 10 Ma. Smith et al. (2002) point out, however, that the basalt flows preserve a northward paleoslope from the Jemez Mountains that was eroded on southwest-dipping rift-basin fill (Fig. 2). The angular unconformity between the basalt and underlying strata implies that most basin subsidence occurred before basalt extrusion. Figure 3 illustrates the correlation of Cerro Pedernal stratigraphy to the stratigraphic section in the Cañones area in the western Rio Grande rift and only 5 km east of the peak. The correlation of rift-basin stratigraphy mapped by Manley (1982) and Moore (2000) to the undeformed section at Cerro Pedernal highlights evidence for the pre-basalt rifting history. Middle Miocene strata of the Tesuque Formation thicken dramatically from about 65 m at Cerro Pedernal to 330 m southeast of Cañones, indicating substantial movement on the Gonzales and Cañones faults (Figs. 2 and 3) before eruption of the Lobato Basalt. The underlying Abiquiu Formation consists of two thick members, a lower member of Precam","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126570720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taphonomic analysis of a fire-related Upper Triassic vertebrate fossil assemblage from north-central New Mexico","authors":"K. Zeigler, A. Heckert, S. Lucas, G. Spencer","doi":"10.56577/ffc-56.341","DOIUrl":"https://doi.org/10.56577/ffc-56.341","url":null,"abstract":"—The Snyder quarry is an Upper Triassic bonebed located in north-central New Mexico. The locality is stratigraphically high in the Petrified Forest Formation of the Chinle Group, and tetrapod biostratigraphy places it in the Revueltian land-vertebrate faunachron (mid-Norian in age: 210-215 Ma). This site has yielded the remains of a wide variety of organisms, ranging from terrestrial and aquatic vertebrates to aquatic invertebrates, as well as a substantial volume of charcoalified wood. A taphonomic analysis of both the biological material and the associated sediments indicates that the bonebed is the result of a catastrophic mass mortality event. The sediments of the bonebed contain rip-up clasts from the surrounding floodplain, a significant portion of the bone and wood is aligned, there is a high density of bones over a large area, and a moderate degree of hydraulic sorting of the skeletal material, indicating brief transport and rapid deposition of the bonebed. There is no evidence of abrasion on the bones, indicating that transport was minimal. The skeletal material is associated, with no evidence of substantial weathering or vertebrate scavenging, reflecting a rapid burial of partially dissociated carcasses. A survivorship curve constructed for the phytosaurs, the dominant taxonomic group, shows a thanatocoenosis that matches the biocoenosis for a reptile population. Scanning electron microscopy of the charcoalified wood reveals that the internal structure of the cell walls has been homogenized, and the reflectance of the charcoal is significantly higher than that of other forms of plant fossil preservation. These two pieces of data are evidence that the wood was burned in a moderate temperature (300-450°C) ground fire. Thus, both the sedimentological and biological data from the Snyder quarry best fit the scenario of a catastrophic, Late Triassic wildfire.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131823381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tierra Amarilla to El Vado Dam: Third-day supplemental road log","authors":"S. Lucas, Donald E. Owen, K. Zeigler, A. Hunt, A. Heckert","doi":"10.56577/ffc-56.69","DOIUrl":"https://doi.org/10.56577/ffc-56.69","url":null,"abstract":"","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124245317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution and biochronology of Camarasaurus (Dinosaria, Sauropoda) from the Jurassic Morrison Formation of the Rocky Mountain Region","authors":"T. Ikejiri","doi":"10.56577/ffc-56.367","DOIUrl":"https://doi.org/10.56577/ffc-56.367","url":null,"abstract":"––The stratigraphic distribution of fossil remains of Camarasaurus (Dinosauria, Sauropoda) allows recognition of five biozones in the upper Jurassic Morrison Formation: (1) no Camarasaurus Zone (early-mid Kimmeridgian), (2) Camarasaurus grandis Zone (mid Kimmeridgian), (3) C. lentus Zone (late Kimmeridgian), (4) transition Zone (early Tithonian), and (5) C. supremus Zone (Tithonian). Paleobiogeographically, C. grandis is known from south and central Wyoming, central Colorado, and New Mexico; C. lentus occurs in Wyoming and Utah and C. supremus in south-central Colorado to western Oklahoma. However, the geographic occurrences may only reflect stratigraphic distribution as locally appropriate beds may not be exposed or were eroded. Camarasaurus might have a much wider distribution in the Rocky Mountain area than indicated by its distribution of the fossil remains. Additionally, the data provide new insights into the taxonomy of Camarasaurus. FIGURE 1. Geological features in the Rocky Mountain region and major dinosaur quarries in the Morrison Formation. The map is modified from King (1977, fig. 74). Areal definition of the Morrison Formation is based on Turner and Peterson (1999).","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128055915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rio Grande rift to the Colorado Plateau. First-day road log from Espanola to Abiquiu, Youngsville, Coyote, Gallina and Ghost Ranch","authors":"S. Lucas, D. Koning, A. Heckert, K. Zeigler, A. Hunt, Donald E. Owen, F. Maldonado, William R. Berglof","doi":"10.56577/ffc-56.1","DOIUrl":"https://doi.org/10.56577/ffc-56.1","url":null,"abstract":"","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115000671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}