Geology of the Chama Basin最新文献

{"title":"The Hayden Quarry, a new Upper Triassic fossil locality at Ghost Ranch, New Mexico","authors":"Alex Downs","doi":"10.56577/ffc-56.355","DOIUrl":"https://doi.org/10.56577/ffc-56.355","url":null,"abstract":"—The Hayden quarry is a recently discovered fossil locality in the Upper Triassic Petrified Forest Formation at the Ghost Ranch Conference Center. The quarry is at a similar stratigraphic level to the nearby NMMNH Snyder quarry and produces a similar but less diverse fauna.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"78 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":"126934646","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":"Contrasts in Late Pleistocene to Holocene fluvial behavior along the Middle Rio Chama","authors":"L. Persico, G. Meyer, J. Frechette, Jennifer New, Chris Hepler","doi":"10.56577/ffc-56.432","DOIUrl":"https://doi.org/10.56577/ffc-56.432","url":null,"abstract":"— A preliminary analysis of terraces along the middle Rio Chama indicates that there was an episode of rapid valley aggradation within the last 700 years. Input of sandy sediment from Mesozoic and Cenozoic sedimentary and volcaniclastic rocks in the drainage basin was apparently sufficient to overwhelm discharges in the study reach and cause substantial aggradation, despite snowmelt runoff from the high-elevation upper basin. 433 CONTRASTS OF LATE PLEISTOCENE TO HOLOCENE FLUVIAL BEHAVIOR lar western rivers (Williams and Wolman, 1984). This reach of the Rio Chama exhibits some striking contrasts in fluvial activity from late Pleistocene to modern time.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"2 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":"128576094","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":"Definition and correlation of the Lamyan: A new biochronological unit for the nonmarine Late Carnian (Late Triassic)","authors":"A. Heckert","doi":"10.56577/ffc-56.357","DOIUrl":"https://doi.org/10.56577/ffc-56.357","url":null,"abstract":"The Sonsela Member of the Petrified Forest Formation at Petrified Forest, Arizona and the Tres Lagunas Member of the Santa Rosa Formation in east-central New Mexico yield vertebrate fossil assemblages (faunas) that are intermediate in composition between the Adamanian and Revueltian lvfs in that they include co-occurrences of the phytosaurs Rutiodon and \u0000Pseudopalatus and the unique taxon Typothorax antiquum. These faunas define an upper subdivision of Adamanian time that we refer to as the Lamyan sub-faunachron. The earlier Adamanian is distinguished as the St. Johnsian sub-faunachron. This refinement demonstrates the utility of defining biochronologic units in that it spurs detailed examination of biostratigraphy and lithostratigraphy. The Lamyan provides evidence that there is no major tetrapod extinction within the Late Triassic, specifically \u0000at the end of the Carnian.","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":"124098554","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":"Jurassic stratigraphy in the Chama Basin, northern New Mexico","authors":"S. Lucas, A. Hunt, J. Spielmann","doi":"10.56577/ffc-56.182","DOIUrl":"https://doi.org/10.56577/ffc-56.182","url":null,"abstract":"—Jurassic strata have an extensive outcrop belt in the Chama Basin of Rio Arriba County, New Mexico, and are assigned to the Entrada, Todilto, Summerville and Morrison formations. Previous workers have identified the Morrison Formation in the Chama Basin as the strata between the Jurassic Todilto Formation and the Cretaceous Burro Canyon Formation, or they have identified a “Wanakah Formation” between the Todilto and Morrison base. However, recent restudy of the Jurassic section in the Chama Basin (especially at Ghost Ranch and at Mesa Alta) indicate the Jurassic section is: (1) Slick Rock Member of the Entrada Sandstone, 60 to 76 m of trough crossbedded and ripple laminated sandstone; (2) Todilto Formation, consisting of a lower limestone-dominated Luciano Mesa Member (2-8 m thick) and an upper, gypsum-dominated Tonque Arroyo Member (0-30 m thick); (3) Summerville Formation, 74 to 111 m of thinly and cyclically-bedded, grayish red and yellowish gray siltstone, sandy siltstone, fine gypsiferous sandstone and mudstone; (4) Bluff Sandstone (Junction Creek Member), 30 to 43 m of light gray, very fine grained, well sorted sandstone with crossbeds in thick sets; (5) Recapture Member of Bluff Sandstone, 6 to 14 m of grayish red gypsiferous siltstone, fine sandstone and minor mudstone; and (6) Brushy Basin Member of Morrison Formation, 41 to 68 m of variegated pale greenish gray and reddish brown, bentonitic mudstone and a few beds of trough-crossbedded, pebbly sandstone. This revised lithostratigraphy is consistent with regional lithostratigraphy that recognizes the Summerville Formation across northern New Mexico, and the Bluff Sandstone in the eastern San Juan Basin, adjacent to the Chama Basin. Only the Slick Rock Member of the Entrada Sandstone is present, and this suggests a depositional high in the Chama Basin area during the time of the Carmel transgression. The absence of a basal Salt Wash Member of the Morrison Formation in the Chama Basin is a striking departure from the regional stratigraphy. We interpret this absence as direct evidence of the J-5 unconformity, which separates the base of the Morrison (usually the Salt Wash Member, but in the Chama Basin the Brushy Basin Member) from underlying San Rafael Group strata. FIGURE 1. Distribution of Jurassic strata in the Chama Basin showing location of measured sections at Mesa Alta and Ghost Ranch and of Echo Amphitheater. 183 JURASSIC STRATIGRAPHY IN THE CHAMA BASIN lower member (limestone) and an upper member (gypsum). They also divided the Morrison Formation into a lower member (up to 400 ft thick), “an alternating sequence of pale brown, chocolate, or deep purple mudstones and white to pale gray siltstones” (p. 13), overlain by the Brushy Basin Member. Dane and Bachman (1965) similarly assigned Jurassic strata in the Chama Basin to the San Rafael Group (Entrada and Todilto formations) and Morrison Formation. Ridgley (1977, 1986, 1989) revised the Jurassic stratigraphic nomenclature in the C","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"33 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":"115799662","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 vertebrate fauna of the Upper Triassic (Revueltian: Early-Mid Norian) Painted Desert Member (Petrified Forest Formation: Chinle Group) in the Chama Basin, northern New Mexico","authors":"A. Heckert","doi":"10.56577/ffc-56.302","DOIUrl":"https://doi.org/10.56577/ffc-56.302","url":null,"abstract":"The Upper Triassic Painted Desert Member of the Petrified Forest Formation in north-central New Mexico yields one of the most extensive and significant Revueltian (early-mid Norian) tetrapod faunas known. Particularly significant aspects of this fauna are: (1) its long history of collection and study, including designation of important type specimens; and (2) the richness \u0000of the unit, including no fewer than three major vertebrate quarries (the Canjilon, Snyder, and Hayden quarries). Beginning with the work of Cope and extending to the present day, the bulk of the Triassic vertebrates recovered from the Chama Basin have been derived from the Painted Desert Member. This includes tetrapod faunas collected at Gallina, Orphan Mesa, and the Canjilon, Snyder, and Hayden quarries. Although any one of these localities can be exceptionally rich, the Painted Desert Member fauna in the Chama Basin is a relatively low-diversity assemblage dominated by the phytosaur Pseudopalatus and the \u0000aetosaur Typothorax. The vast majority of the known diversity of the unit in the Chama Basin was derived from a single locality, the Snyder quarry. We also review the stratigraphic and biostratigraphic evidence that suggest that this fauna may be slightly younger (Lucianoan) than the type Revueltian (Barrancan) assemblage, although this argument is weakened by the fact that it is based at least in part on the absence of characteristic Revueltian (Barrancan) taxa such as Revueltosaurus callenderi.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"2 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":"131998447","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":"Taphonomy of the Lower Permian Cardillo Quarry, Chama Basin, north-central New Mexico","authors":"A. Heckert","doi":"10.56577/ffc-56.297","DOIUrl":"https://doi.org/10.56577/ffc-56.297","url":null,"abstract":"The Lower Permian Cardillo quarry is located near Arroyo del Agua, in the Chama Basin in north-central New \u0000Mexico. The quarry is stratigraphically high in the El Cobre Canyon Formation of the Cutler Group, which is Wolfcampian in \u0000age. During excavations in 1979, 1980 and 2002-2004, the remains of the labyrinthodont amphibian Eryops, the diadectamorph \u0000Diadectes, a captorhinid reptile, a varanopseid pelycosaur, and the pelycosaurs Sphenacodon and Ophiacodon were recovered \u0000from the Cardillo quarry. Taphonomic analysis reveals that this locality is an attritional fossil assemblage. The bones lie within \u0000a series of three distinct, pedogenically modified conglomerates that also include calcrete nodules, chert, quartzite and other \u0000siliceous pebbles. The skeletal material is mostly disarticulated, though two partially articulated pelycosaur skeletons were \u0000recovered from overbank sediments above the uppermost conglomerate. Isolated skeletal elements and bone fragments are in \u0000various stages of weathering and abrasion. The assemblage was not hydraulically sorted because all three Voorhies groups are \u0000well represented. The Cardillo quarry assemblage was formed by a series of crevasse splays that incorporated bones, bone fragments \u0000and basement clasts (siliceous pebbles). Thus, it is a classic example of a time-averaged vertebrate fossil assemblage.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"3 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":"115823224","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":"Vertebrate fauna of the Upper Triassic Mesa Montosa Member (Petrified Forest Formation, Chinle Group), Chama Basin, northern New Mexicio","authors":"K. Zeigler, S. Lucas, V. L. Morgan, G. Spencer","doi":"10.56577/ffc-56.335","DOIUrl":"https://doi.org/10.56577/ffc-56.335","url":null,"abstract":"—The vertebrate fauna of the Mesa Montosa Member of the Petrified Forest Formation of the Chinle Group in the Chama Basin of northern New Mexico is generally not well known. However, recent work has greatly expanded the known vertebrate fauna from this unit. Taxa include the metoposaurid amphibian cf. Buettneria sp., the phytosaur Pseudopalatus buceros (Cope) as well as indeterminate phytosaurs (Parasuchidae), the aetosaurs Typothorax coccinarum and Paratypothorax sp., the enigmatic archosaur Vancleavea sp. and theropod dinosaurs. An unusual vertebra and a distinctive shell(?) fragment may pertain to a pterosaur and a turtle, respectively, both of which are rare in the Chinle Group. Other fossil material recovered from the Mesa Montosa Member includes numerous vertebrate coprolites, charcoal and unionid bivalve shells. The assemblage of fossil vertebrates indicates that the Mesa Montosa Member is Revueltian in age. Most of the fossils were collected from a coarse brown sandstone that contains some pebbles and calcrete nodules and is less than a meter below the contact between the Mesa Montosa Member and the overlying Painted Desert Member. These fossils are disarticulated and fragmentary, very few of the fossils are unweathered and many are abraded to the point where identification is impossible. Thus, these fossils represent a time-averaged attritional assemblage that is most likely derived from the floodplain near the channel system that deposited the sandstone. More complete skeletal elements have been recovered from a green shaley siltstone underlying the sandstone, but fossils from this layer are much less abundant.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"44 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":"114498997","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":"Dinosaurs, pollen, and the Cretaceous-Tertiary boundary in the San Juan Basin","authors":"R. M. Sullivan, S. Lucas, D. R. Braman, G. Spencer","doi":"10.56577/ffc-56.395","DOIUrl":"https://doi.org/10.56577/ffc-56.395","url":null,"abstract":"A BSTRACT .— In the San Juan Basin, New Mexico, the Ojo Alamo Formation includes two members, the upper Kimbeto Member and the lower Naashoibito Member (previously assigned to the underlying Kirtland Formation). The Naashoibito Member produces dinosaur fossils, as does the De-na-zin Member of the Kirtland Formation, which lies unconformably beneath it. A lignite bed in the upper part of the De-na-zin Member has been identified as the horizon of a major unconformity and the source of some Paleocene palynomorphs. The overlying dinosaur remains in the Naashoibito Member thus have been assigned a Paleocene age, but new pollen data refute this interpretation. The dinosaurs from the Naashoibito Member are not well-known, but late Maastrichtian (Lancian) dinosaur taxa ( Torosaurus latus and Tyrannosaurus rex ), as well as the early Maastrichtian Torosaurus utahensis , are not demonstrably present in this unit, despite previous claims. Vertebrate biostratigraphy suggests an early Maastrichtian age for the Naashoibito Member of the Ojo Alamo Formation, and palynological analyses of this unit does not support a Paleocene age; thus there are no Paleocene (non-avian) dinosaurs in the San Juan Basin.","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"10 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":"114927378","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":"Proposed members of the Chamita Formation, north-central New Mexico","authors":"D. Koning, S. Aby","doi":"10.56577/ffc-56.258","DOIUrl":"https://doi.org/10.56577/ffc-56.258","url":null,"abstract":"A BSTRACT .— New geologic mapping and stratigraphic considerations lead us to favor retaining the term Chamita Formation, albeit with a geographic limitation for two of its five proposed members. West of the Rio Grande in the north-central Española","PeriodicalId":345302,"journal":{"name":"Geology of the Chama Basin","volume":"28 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":"121891223","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":"Paleomagnetism and mangetostratigraphy of the Upper Triassic Petrified Forest and Poleo formations, north-central New Mexico, and the Bluewater Creek and Lower Petrified Forest Formations, central New Mexico","authors":"K. Zeigler, J. Geissman, S. Lucas","doi":"10.56577/ffc-56.115","DOIUrl":"https://doi.org/10.56577/ffc-56.115","url":null,"abstract":"—As demonstrated by vertebrate biostratigraphy and palynostratigraphy, the Upper Triassic Chinle Group spans most of the Late Triassic. The Chinle Group was deposited by a fluvial system and consists predominantly of red to purple mudstones with some red to orange siltstones and red to buff sandstones. In the Chama basin, north-central New Mexico, both lower and upper Chinle Group strata are well-exposed and are being used to develop a more complete magnetic reversal chronology for the Late Triassic for the American Southwest. Our sampling methods concentrate on hematitic mudrocks, using an intricate block sampling technique. These materials typically carry a well-defined, well-grouped magnetization dominated by pigmentary hematite that is unblocked below about 660oC. For example, a single horizon (level 39) in the Painted Desert Member of the Petrified Forest Formation yields an estimated site mean of D=172.9o, I=7.0o, α95=5.5o and k=102.5 (N = 8 independent samples). Indurated, coarser-grained deposits are sampled by more conventional methods. Sandstones and siltstones of the Poleo Formation contain both detrital and authigenic hematite and some detrital magnetite as the magnetization carriers and typically yield a well-defined magnetization at the site (single bed) level (e.g., site 11, eight independent samples, yields an estimated site mean of D=187.4o, I=0.8o, α95=3.4o and k=268.1). A very preliminary polarity reversal stratigraphy has been developed for the Poleo and Petrified Forest formations in the Chama basin. The Petrified Forest Formation includes multiple polarity intervals. All accepted sites in the Poleo Formation are of reverse polarity. The upper part of the Bluewater Creek Formation and lower Blue Mesa Member (Petrified Forest Formation) in the Zuni Mountains, central New Mexico, appear to be entirely of reverse polarity. FIGURE 1. Distribution of Triassic outcrop area (approximates outline of Chinle basin) (from Molina-Garza et al., 1993), with expanded view of Chama basin Chinle Group outcrops. 1 = Abiquiu Dam, 2 = Coyote Amphitheater, star = Zuni Mountains. 116 ZEIGLER, GEISSMAN, AND LUCAS as well as tie the magnetostratigraphy of these rocks to a tuffaceous, zircon-bearing sandstone within the section for which we are obtaining a high-precision U-Pb zircon age. Here we present preliminary magnetostratigraphic data from the mudstone-dominated Petrified Forest Formation and the Poleo Sandstone, as well as the Bluewater Creek Formation and Blue Mesa Member (Petrified Forest Formation), of the Chinle Group. GEOLOGIC SETTING AND STRATIGRAPHY The Chinle Group was deposited in a back-arc basin in western Pangea by a large and widespread fluvial system (Stewart et al., 1972; Blakey and Gubitosa, 1983; Dubiel, 1987) and consists predominantly of red mudstones, with lesser orange siltstones and buff sandstones. Upper Triassic strata in the Chama basin of north-central New Mexico have been assigned to six formations (in ascending orde","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":"130500394","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}