Mississippian strata of southeastern New Mexico are Kinderhookian to Chesterian in age. In Eddy, Lea, and southern Chaves Counties, depth to the top of the Mississip- pian ranges from 5,500 ft in the northwest to 17,000 ft in the southeast. Lower Mississip- pian (Kinderhookian and Osagian) strata are 0-800 ft thick and comprise marine limestones and minor shales and chert. Upper Mississip- pian (Meramecian and Chesterian) strata are 0-600 ft thick and comprise shallow marine limestones and shales. Within the Upper Mis- sissippian section there is a sharp transition from shelf deposits dominated by limestones in the north to the basinal Barnett Shale in the south. Stratigraphic analyses suggest a Missis- sippian ancestry for the Tatum Basin and for the Lower Permian shelf-basin boundary. Forty-five gas and oil pools have been productive from Mississippian reservoirs in Eddy, Lea, and southern Chaves Counties. Twenty-seven pools have been productive from Upper Mississippian reservoirs, and 14 have been productive from Lower Missis- sippian reservoirs. Four gas pools have been productive from both Upper and Lower Mis- sissippian reservoirs. The Mississippian play is one of the least developed plays in south- eastern New Mexico and has yielded a cumu- lative 46 billion ft3 (BCF) gas and 1.4 million bbls oil and condensate (MMBO) from the 45 pools in Eddy, Lea, and southern Chaves Counties. Most production has been obtained from Chesterian limestone reservoirs of the northern shelf. Chesterian reservoirs have been developed in the paleostructurally low Tatum Basin where uppermost Chesterian strata were preserved before deposition of Early Pennsylvanian sediments. Four subplays are identified in the Mississip- pian of Eddy, Lea, and southern Chaves Coun- ties of southeastern New Mexico: (1) Chester shallow marine limestones in the Tatum Basin on the northern shelf; (2) Upper Mississip- pian limestones interbedded with Barnett shales just south of the shelf-basin transition; (3) small and widely disseminated reservoirs in lower Mississippian limestones in the north; and (4) the as-yet untested Barnett Shale in the southern basin.
{"title":"Mississippian strata of southeastern New Mexico: distribution, structure, and hydrocarbon plays","authors":"R. Broadhead","doi":"10.58799/nmg-v31n3.65","DOIUrl":"https://doi.org/10.58799/nmg-v31n3.65","url":null,"abstract":"Mississippian strata of southeastern New Mexico are Kinderhookian to Chesterian in age. In Eddy, Lea, and southern Chaves Counties, depth to the top of the Mississip- pian ranges from 5,500 ft in the northwest to 17,000 ft in the southeast. Lower Mississip- pian (Kinderhookian and Osagian) strata are 0-800 ft thick and comprise marine limestones and minor shales and chert. Upper Mississip- pian (Meramecian and Chesterian) strata are 0-600 ft thick and comprise shallow marine limestones and shales. Within the Upper Mis- sissippian section there is a sharp transition from shelf deposits dominated by limestones in the north to the basinal Barnett Shale in the south. Stratigraphic analyses suggest a Missis- sippian ancestry for the Tatum Basin and for the Lower Permian shelf-basin boundary. Forty-five gas and oil pools have been productive from Mississippian reservoirs in Eddy, Lea, and southern Chaves Counties. Twenty-seven pools have been productive from Upper Mississippian reservoirs, and 14 have been productive from Lower Missis- sippian reservoirs. Four gas pools have been productive from both Upper and Lower Mis- sissippian reservoirs. The Mississippian play is one of the least developed plays in south- eastern New Mexico and has yielded a cumu- lative 46 billion ft3 (BCF) gas and 1.4 million bbls oil and condensate (MMBO) from the 45 pools in Eddy, Lea, and southern Chaves Counties. Most production has been obtained from Chesterian limestone reservoirs of the northern shelf. Chesterian reservoirs have been developed in the paleostructurally low Tatum Basin where uppermost Chesterian strata were preserved before deposition of Early Pennsylvanian sediments. Four subplays are identified in the Mississip- pian of Eddy, Lea, and southern Chaves Coun- ties of southeastern New Mexico: (1) Chester shallow marine limestones in the Tatum Basin on the northern shelf; (2) Upper Mississip- pian limestones interbedded with Barnett shales just south of the shelf-basin transition; (3) small and widely disseminated reservoirs in lower Mississippian limestones in the north; and (4) the as-yet untested Barnett Shale in the southern basin.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174213","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}
A small assemblage of invertebrate fossils from the Cretaceous Dakota Sandstone at Arroyo del Yeso near Ghost Ranch, Rio Arriba County, New Mexico, is the first age-diagnostic fossil assemblage documented from the intertongued Dakota–Mancos succession in the Chama Basin. The fossils are assigned to the bivalves Legumen sp., Exogyra sp., Inoceramus arvanus Stephenson, and I. prefragilis Stephenson and the ammonite cf. Acanthoceras amphibolum Morrow. They indicate the Acanthoceras amphibolum Zone of middle Cenomanian age and support lithostratigraphic identification of the fossil-bearing strata as the Paguate Sandstone Tongue of the Dakota Sandstone.
{"title":"Cenomanian invertebrate assemblage from the Dakota Sandstone near Ghost Ranch, Rio Arriba County, New Mexico","authors":"S. Lucas, L. Rinehart, S. Kelley","doi":"10.58799/nmg-v31n3.59","DOIUrl":"https://doi.org/10.58799/nmg-v31n3.59","url":null,"abstract":"A small assemblage of invertebrate fossils from the Cretaceous Dakota Sandstone at Arroyo del Yeso near Ghost Ranch, Rio Arriba County, New Mexico, is the first age-diagnostic fossil assemblage documented from the intertongued Dakota–Mancos succession in the Chama Basin. The fossils are assigned to the bivalves Legumen sp., Exogyra sp., Inoceramus arvanus Stephenson, and I. prefragilis Stephenson and the ammonite cf. Acanthoceras amphibolum Morrow. They indicate the Acanthoceras amphibolum Zone of middle Cenomanian age and support lithostratigraphic identification of the fossil-bearing strata as the Paguate Sandstone Tongue of the Dakota Sandstone.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174005","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}
Stratigraphic studies and geologic mapping on the Abiquiu 7.5-min quadrangle have led to revision of the stratigraphic nomenclature for the Oligocene to Miocene Abiquiu Formation in north-central New Mexico. The Abiquiu Formation had previously been defined to include informal upper, middle (Pedernal chert member), and lower members. The basement-derived conglomeratic lower member in the northern Jemez Mountains and Abiquiu embayment is here redefined. We propose removing the “lower member” from the Abiquiu Formation because provenance of these coarse sediments is dramatically different than the volcaniclastic strata of the “upper member.” Furthermore, we propose that the term “lower member of the Abiquiu Formation” be replaced with an existing unit name, the Ritito Conglomerate of Barker (1958), and that the name Abiquiu Formation be restricted to the volcaniclastic succession. The lower part of the Ritito Conglomerate in Arroyo del Cobre on the Abiquiu quadrangle is 47 m (155 ft) thick and is composed of arkosic conglomeratic beds interbedded with arkosic sands and siltstones. Clasts include, in descending order of abundance, Proterozoic quartzite, granite, metavolcanic rocks, quartz, schist, and gneiss and a trace of Mesozoic sandstone and Paleozoic chert. Clasts are predominantly of pebble and cobble size but range from granule to boulder size. Paleocurrent data collected in the Arroyo del Cobre area indicate that the Ritito Conglomerate was deposited by a south-flowing river system during the Oligocene, eroding Laramide highlands such as the Tusas Mountains to the northeast, which contain predominantly Proterozoic rocks. This depositional setting has also been suggested by previous workers. The middle member or Pedernal chert member is present both at the top of the Ritito Conglomerate and as lenses within the lower part of the Abiquiu Formation. This post-depositional diagenetic chert remains an informal unit called the Pedernal chert.
对新墨西哥州中北部阿比基乌7.5分钟四边形地层研究和地质填图对渐新世至中新世阿比基乌组地层命名进行了修订。以前，Abiquiu组被定义为非正式的上部、中部(Pedernal燧石岩)和下部。在此重新定义了Jemez山脉北部和Abiquiu盆地的基底源砾岩下段。我们建议将“下段”从阿比奎乌组中移除，因为这些粗粒沉积物的物源与“上段”的火山碎屑地层有很大的不同。此外，我们建议将“阿比基乌组下段”一词替换为现有的单元名称，即Barker的Ritito砾岩(1958)，并将阿比基乌组的名称限制在火山碎屑演替中。位于Arroyo del Cobre的Ritito砾岩下部厚47米(155英尺)，由黑质砾岩层与黑质砂和粉砂岩互层组成。碎屑由多到少依次为元古代石英岩、花岗岩、变质火山岩、石英、片岩和片麻岩，并有少量中生代砂岩和古生代燧石。碎屑主要为卵石和鹅卵石大小，但大小从颗粒到卵石不等。在Arroyo del Cobre地区收集的古流数据表明，Ritito砾岩是在渐新世由一个向南流动的河流体系沉积的，它向东北侵蚀了以元古代岩石为主的Laramide高地，如Tusas山脉。这一沉积环境也被前人提出过。中间岩段或尖岩段既存在于Ritito砾岩顶部，也存在于Abiquiu组下部的透镜体中。这种沉积后成岩燧石仍然是一个非正式的单位，称为板岩。
{"title":"Revisions to the stratigraphic nomenclature of the Abiquiu Formation, Abiquiu and contiguous areas, north-central New Mexico","authors":"F. Maldonado, S. Kelley","doi":"10.58799/nmg-v31n1.3","DOIUrl":"https://doi.org/10.58799/nmg-v31n1.3","url":null,"abstract":"Stratigraphic studies and geologic mapping on the Abiquiu 7.5-min quadrangle have led to revision of the stratigraphic nomenclature for the Oligocene to Miocene Abiquiu Formation in north-central New Mexico. The Abiquiu Formation had previously been defined to include informal upper, middle (Pedernal chert member), and lower members. The basement-derived conglomeratic lower member in the northern Jemez Mountains and Abiquiu embayment is here redefined. We propose removing the “lower member” from the Abiquiu Formation because provenance of these coarse sediments is dramatically different than the volcaniclastic strata of the “upper member.” Furthermore, we propose that the term “lower member of the Abiquiu Formation” be replaced with an existing unit name, the Ritito Conglomerate of Barker (1958), and that the name Abiquiu Formation be restricted to the volcaniclastic succession. The lower part of the Ritito Conglomerate in Arroyo del Cobre on the Abiquiu quadrangle is 47 m (155 ft) thick and is composed of arkosic conglomeratic beds interbedded with arkosic sands and siltstones. Clasts include, in descending order of abundance, Proterozoic quartzite, granite, metavolcanic rocks, quartz, schist, and gneiss and a trace of Mesozoic sandstone and Paleozoic chert. Clasts are predominantly of pebble and cobble size but range from granule to boulder size. Paleocurrent data collected in the Arroyo del Cobre area indicate that the Ritito Conglomerate was deposited by a south-flowing river system during the Oligocene, eroding Laramide highlands such as the Tusas Mountains to the northeast, which contain predominantly Proterozoic rocks. This depositional setting has also been suggested by previous workers. The middle member or Pedernal chert member is present both at the top of the Ritito Conglomerate and as lenses within the lower part of the Abiquiu Formation. This post-depositional diagenetic chert remains an informal unit called the Pedernal chert.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174334","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}
G. Morgan, E. Lander, C. Cikoski, R. Chamberlin, D. Love, L. Peters
A partial fossilized skeleton of an oreodont (Mammalia: Artiodactyla: Oreodontidae) was discovered in 2008 eroding from the wall of an arroyo on the Bosque del Apache National Wildlife Refuge near San Antonio in Socorro County, central New Mexico. The fossil was preserved in a semi-indurated, sandy stream deposit in a distal piedmont facies of the Miocene Popotosa Formation. The specimen includes a nearly intact skull and attached mandible that were associated with a partial articulated postcranial skeleton. The postcranial skeleton consists of a complete set of thoracic, lumbar, and sacral vertebrae, most of the ribs, which are still attached to their respective thoracic vertebrae, both wrists (distal radius and ulna, carpals, proximal metacarpals), left innominate, and an incomplete left hind limb (femur, tibia, fibula, tarsals). A highly unusual feature is the preservation of an ossified larynx and the delicate hyoid bones. The Bosque del Apache oreodont is identified as Merychyus major major, a member of the subfamily Ticholeptinae. It is the only record of an oreodont from the Popotosa Formation. The specimen represents one of the largest individuals of the genus currently known and the most derived and tapir-like in the degree of posterior retraction of its external narial opening. Merychyus major major is restricted to faunas of early late Miocene (latest Clarendonian) age. Geologic age constraints for the Popotosa Formation in the general vicinity of the oreodont site are provided by two 40Ar/39Ar radioisotopic ages. An age of 14.59 ± 0.05 Ma was obtained on pumice clasts in fluvial sandstones near the base of the local section, and an age of 8.57 ± 0.26 Ma was determined for a basalt flow interbedded with conglomerates near the top. The oreodont skeleton was found in strata somewhat below the dated basalt. The radiometric dates for the Popotosa Formation are consistent with those from the Dove Spring Formation of southern California where the stratigraphic range of M. major major is bracketed by smaller-bodied subspecies of M. major and by vitric tuff units that have been deter mined to be 11.19 ± 0.10 Ma in age, below, and 9.36 ± 0.20 Ma, above.
2008年，在新墨西哥州中部索科罗县圣安东尼奥附近的博斯克德尔阿帕奇国家野生动物保护区，人们在一座被侵蚀的阿罗约墙上发现了一具oreodon(哺乳类:偶蹄目:Oreodontidae)的部分骨骼化石。该化石保存在中新世Popotosa组远山前相的半硬化砂流沉积中。该标本包括一个几乎完整的头骨和附着的下颌骨，与部分铰接的颅后骨骼相关。颅后骨骼包括一套完整的胸椎、腰椎和骶骨，大部分肋骨仍与各自的胸椎相连，两个手腕(桡骨远端、尺骨远端、腕骨、掌骨近端)、左无名骨和一个不完整的左后肢(股骨、胫骨、腓骨、跗骨)。一个非常不寻常的特征是保留了骨化的喉部和精致的舌骨。boque del Apache oreodo被鉴定为Merychyus major major，是Ticholeptinae亚科的一员。这是Popotosa组唯一的oreodon记录。该标本代表了目前已知的该属中最大的个体之一，并且在其外部鼻窦开口的后缩回程度上最衍生和像貘。major major Merychyus仅限于晚中新世早期(克拉伦东晚期)的动物群。两个40Ar/39Ar的放射性同位素年龄为该oreodon遗址附近的Popotosa组提供了地质年龄限制。局部剖面底部附近河流砂岩浮石碎屑的年龄为14.59±0.05 Ma，顶部附近与砾岩互层的玄武岩流的年龄为8.57±0.26 Ma。在年代久远的玄武岩之下的地层中发现了oreodon骨架。Popotosa组的放射性测年结果与南加州Dove Spring组的一致，该组的地层范围被较小的M. major亚种和玻璃凝灰岩单元所包围，年龄在11.19±0.10 Ma以下，在9.36±0.20 Ma以上。
{"title":"The oreodont Merychyus major major (Mammalia: Artiodactyla: Oreodontidae) from the Miocene Popotosa Formation, Bosque del Apache National Wildlife Refuge, Socorro County, New Mexico","authors":"G. Morgan, E. Lander, C. Cikoski, R. Chamberlin, D. Love, L. Peters","doi":"10.58799/nmg-v31n4.91","DOIUrl":"https://doi.org/10.58799/nmg-v31n4.91","url":null,"abstract":"A partial fossilized skeleton of an oreodont (Mammalia: Artiodactyla: Oreodontidae) was discovered in 2008 eroding from the wall of an arroyo on the Bosque del Apache National Wildlife Refuge near San Antonio in Socorro County, central New Mexico. The fossil was preserved in a semi-indurated, sandy stream deposit in a distal piedmont facies of the Miocene Popotosa Formation. The specimen includes a nearly intact skull and attached mandible that were associated with a partial articulated postcranial skeleton. The postcranial skeleton consists of a complete set of thoracic, lumbar, and sacral vertebrae, most of the ribs, which are still attached to their respective thoracic vertebrae, both wrists (distal radius and ulna, carpals, proximal metacarpals), left innominate, and an incomplete left hind limb (femur, tibia, fibula, tarsals). A highly unusual feature is the preservation of an ossified larynx and the delicate hyoid bones. The Bosque del Apache oreodont is identified as Merychyus major major, a member of the subfamily Ticholeptinae. It is the only record of an oreodont from the Popotosa Formation. The specimen represents one of the largest individuals of the genus currently known and the most derived and tapir-like in the degree of posterior retraction of its external narial opening. Merychyus major major is restricted to faunas of early late Miocene (latest Clarendonian) age. Geologic age constraints for the Popotosa Formation in the general vicinity of the oreodont site are provided by two 40Ar/39Ar radioisotopic ages. An age of 14.59 ± 0.05 Ma was obtained on pumice clasts in fluvial sandstones near the base of the local section, and an age of 8.57 ± 0.26 Ma was determined for a basalt flow interbedded with conglomerates near the top. The oreodont skeleton was found in strata somewhat below the dated basalt. The radiometric dates for the Popotosa Formation are consistent with those from the Dove Spring Formation of southern California where the stratigraphic range of M. major major is bracketed by smaller-bodied subspecies of M. major and by vitric tuff units that have been deter mined to be 11.19 ± 0.10 Ma in age, below, and 9.36 ± 0.20 Ma, above.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174942","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}
Stratigraphic relations, lithofacies, and radiocarbon chronology of deposits that accumulated in and around the margins of late Pleistocene Lake Otero in south-central New Mexico provide evidence for the timing and relative magnitude of episodes of lake expansion that occurred in the basin during the last ice age. The lower few meters of stratified sediment in exposures along the margins of the winddeflated floor of Tularosa Basin contain gypsiferous lithofacies, sedimentary structures, and fossils indicating deposition along the margins of a shallow saline lake. Radiocarbon dates indicate that these basal nearshore lake deposits accumulated from about 45,000–28,000 14C yrs b.p. A widespread erosional episode removed at least 2 m of lake-margin deposits between 28,000 and 25,000 14C yrs b.p. Lakebeds overlying the erosional unconformity contain a relative abundance of siliciclastic sediment and aquatic fossil organisms suggesting repeated episodes of increased precipitation, surface runoff, and freshening of the lake system. These inferred episodes of increased precipitation and enhanced fluvial activity in the basin began ca. 24,500 14C yrs b.p. and lasted for at least 9 millennia. Highstands of the lake during this period appear to have reached an elevation of ~1,204 m. Details of the history of Lake Otero after 15,500 14C yrs b.p. remain sketchy due to wind deflation of the basin floor and wholesale removal of lacustrine deposits during the Holocene. The evidence from Lake Otero for the onset of maximum pluvial conditions during the late Pleistocene appears to be in good temporal agreement with lacustrine reconstructions from neighboring lake basins to the north and south. Additional study of the deposits associated with Lake Otero, including their abundant and diverse assemblages of aquatic fossil organisms, is clearly warranted.
{"title":"Evidence for late Pleistocene hydrologic and climatic change from Lake Otero, Tularosa Basin, south-central New Mexico","authors":"B. Allen, D. Love, R. Myers","doi":"10.58799/nmg-v31n1.9","DOIUrl":"https://doi.org/10.58799/nmg-v31n1.9","url":null,"abstract":"Stratigraphic relations, lithofacies, and radiocarbon chronology of deposits that accumulated in and around the margins of late Pleistocene Lake Otero in south-central New Mexico provide evidence for the timing and relative magnitude of episodes of lake expansion that occurred in the basin during the last ice age. The lower few meters of stratified sediment in exposures along the margins of the winddeflated floor of Tularosa Basin contain gypsiferous lithofacies, sedimentary structures, and fossils indicating deposition along the margins of a shallow saline lake. Radiocarbon dates indicate that these basal nearshore lake deposits accumulated from about 45,000–28,000 14C yrs b.p. A widespread erosional episode removed at least 2 m of lake-margin deposits between 28,000 and 25,000 14C yrs b.p. Lakebeds overlying the erosional unconformity contain a relative abundance of siliciclastic sediment and aquatic fossil organisms suggesting repeated episodes of increased precipitation, surface runoff, and freshening of the lake system. These inferred episodes of increased precipitation and enhanced fluvial activity in the basin began ca. 24,500 14C yrs b.p. and lasted for at least 9 millennia. Highstands of the lake during this period appear to have reached an elevation of ~1,204 m. Details of the history of Lake Otero after 15,500 14C yrs b.p. remain sketchy due to wind deflation of the basin floor and wholesale removal of lacustrine deposits during the Holocene. The evidence from Lake Otero for the onset of maximum pluvial conditions during the late Pleistocene appears to be in good temporal agreement with lacustrine reconstructions from neighboring lake basins to the north and south. Additional study of the deposits associated with Lake Otero, including their abundant and diverse assemblages of aquatic fossil organisms, is clearly warranted.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174398","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":"Gallery of Geology - Sierra de Cristo Rey","authors":"S. Hook","doi":"10.58799/nmg-v30n3.93","DOIUrl":"https://doi.org/10.58799/nmg-v30n3.93","url":null,"abstract":"","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174239","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}
Order SauriSchia Seeley 1888 Family TyrannoSauridae Osborn 1905 Genus Tyrannosaurus Osborn 1905 cf. T. rex Osborn 1905 Referred specimens—TSJC 2008.1.1; TSJC 2008.1.2; TSJC 2008.1.3. Description—Tooth: A tyrannosaurid tooth (TSJC 2008.1.1) most closely resembles the teeth of “Nanotyrannus lancensis” (or adolescent T. rex, Carr and Williamson 2004) based on crown shape and serration density (N. Larson, pers. comm. 2007). In straight-line measurement, the tooth is approximately 3.5 cm from tip to base. The serration density along the anterior carina is 12/cm, justifying the diagnosis as T. rex (Farlow et al. 1991). The tooth is slightly recurved, blunt, bears denticles along its anterior carina, and is broken at its base. Femur: A limb bone fragment (TSJC 2008.1.2) is also tentatively identified as cf. T. rex. Theropod bones commonly exhibit onion-skin layering in cross section (K. Carpenter, pers. comm. 2007), and this bone seems to lack this feature, although the bone has distinct, differentiable layers. Whereas the bone itself may not be exclusively attributed to a theropod based on its gross histological properties alone, there are quantitative reasons supporting this diagnosis. First, the bone fragment is circular in cross section, and intersecting perpendicular bisectors of lines secant to its intact, periosteal surface suggest a radius of 90 ± 0.1 mm. As long bone circumference is used to estimate a live animal’s weight (Anderson et al. 1985; Alexander 1989), a 90 mm radius corresponds to a biped weighing approximately 5.23 metric tons. In Maastrichtian time in western North America, this value is exclusive to T. rex as far as mass estimates based on long bone circumferences for bipeds are concerned (Alexander 1989; Horner et al. 2004). Second, as T. rex femora have circular cross sections at their midpoint (Farlow et al. 1995; Holtz 2004) and the published growth curve for T. rex is based on midshaft femoral measurements (Erickson et al. 2004), it is possible to quantitatively compare the published growth curve for T. rex with the growth pattern observed in this specimen. Measuring the midpoint of each growth line to an accuracy of ± 0.5 mm along a radial transect, T. rex annual growth markers are exceptionally good predictors for the growth lines observed in this bone (cχ2 = 1.44, df = 6, p-value > 0.95). As T. rex is the only animal known to exhibit this characteristic pattern of growth (Erickson et al. 2004; ChinsamyTuran 2005), this is believed to be a fairly powerful diagnostic test. Significance—Estimated to be about 71 m.y. old based on the age of the Baculites eliasi ammonite zone, these fossils may be among the oldest known T. rex fossils (D. Wolberg, pers. comm. 2007). Institutional abbreviation—TSJC, Trinidad State Junior College Louden-Henritze Archeology Museum.
暴龙目奥斯本霸王龙科奥斯本1905属奥斯本暴龙1905 cf. T. rex Osborn 1905参考标本- tsjc 2008.1.1;TSJC 2008.1.2;TSJC 2008.1.3。描述-牙齿:根据牙冠形状和锯齿密度(N. Larson, pers.)，一颗暴龙的牙齿(TSJC 2008.1.1)与“矮暴龙lancensis”(或幼年霸王龙，Carr and Williamson 2004)的牙齿最相似。通讯,2007)。在直线测量中，牙齿从尖端到基部约为3.5厘米。沿前隆突的锯齿密度为12个/厘米，证明诊断为霸王龙(Farlow et al. 1991)。牙齿稍弯曲，钝，沿其前隆突有小齿，在其基部断裂。股骨:一块肢骨碎片(TSJC 2008.1.2)也被初步鉴定为cf. T. rex。兽脚亚目恐龙的骨头在横截面上通常表现出洋葱皮的分层(K. Carpenter, pers。Comm . 2007)，而这块骨头似乎缺乏这种特征，尽管骨头有明显的、可分化的层。然而，仅根据其大体组织学特征，骨骼本身可能不完全属于兽脚亚目恐龙，但有定量的原因支持这种诊断。首先，骨碎片的横截面呈圆形，与完整骨膜表面割线相交的垂直平分线显示其半径为90±0.1 mm。由于长骨周长被用来估计活体动物的体重(Anderson et al. 1985;Alexander 1989)，一个90毫米的半径对应于一个重约5.23公吨的两足动物。在北美西部的马斯特里赫特时期，根据两足动物的长骨周长来估计质量，这个值是霸王龙所独有的(Alexander 1989;Horner et al. 2004)。其次，由于霸王龙股骨的中点截面呈圆形(Farlow et al. 1995;Holtz 2004)和已发表的暴龙生长曲线是基于股骨中轴测量(Erickson et al. 2004)，因此可以将已发表的暴龙生长曲线与本标本中观察到的生长模式进行定量比较。测量每条生长线的中点沿径向样带的精度为±0.5 mm，霸王龙的年生长标记是该骨骼中观察到的生长线的非常好的预测因子(cχ2 = 1.44, df = 6, p值> 0.95)。由于霸王龙是已知唯一具有这种生长特征的动物(Erickson et al. 2004;ChinsamyTuran 2005)，这被认为是一个相当强大的诊断测试。意义:根据埃利亚斯螺石带的年代估计，这些化石大约有71万年的历史，可能是已知最古老的霸王龙化石之一(D. Wolberg, pers。通讯,2007)。机构缩写- tsjc，特立尼达州立初级学院劳登-亨里茨考古博物馆。
{"title":"Evidence for a Tyrannosaurus rex from southeastern Colorado","authors":"G. Osborn, K. Berry","doi":"10.58799/nmg-v30n1.12","DOIUrl":"https://doi.org/10.58799/nmg-v30n1.12","url":null,"abstract":"Order SauriSchia Seeley 1888 Family TyrannoSauridae Osborn 1905 Genus Tyrannosaurus Osborn 1905 cf. T. rex Osborn 1905 Referred specimens—TSJC 2008.1.1; TSJC 2008.1.2; TSJC 2008.1.3. Description—Tooth: A tyrannosaurid tooth (TSJC 2008.1.1) most closely resembles the teeth of “Nanotyrannus lancensis” (or adolescent T. rex, Carr and Williamson 2004) based on crown shape and serration density (N. Larson, pers. comm. 2007). In straight-line measurement, the tooth is approximately 3.5 cm from tip to base. The serration density along the anterior carina is 12/cm, justifying the diagnosis as T. rex (Farlow et al. 1991). The tooth is slightly recurved, blunt, bears denticles along its anterior carina, and is broken at its base. Femur: A limb bone fragment (TSJC 2008.1.2) is also tentatively identified as cf. T. rex. Theropod bones commonly exhibit onion-skin layering in cross section (K. Carpenter, pers. comm. 2007), and this bone seems to lack this feature, although the bone has distinct, differentiable layers. Whereas the bone itself may not be exclusively attributed to a theropod based on its gross histological properties alone, there are quantitative reasons supporting this diagnosis. First, the bone fragment is circular in cross section, and intersecting perpendicular bisectors of lines secant to its intact, periosteal surface suggest a radius of 90 ± 0.1 mm. As long bone circumference is used to estimate a live animal’s weight (Anderson et al. 1985; Alexander 1989), a 90 mm radius corresponds to a biped weighing approximately 5.23 metric tons. In Maastrichtian time in western North America, this value is exclusive to T. rex as far as mass estimates based on long bone circumferences for bipeds are concerned (Alexander 1989; Horner et al. 2004). Second, as T. rex femora have circular cross sections at their midpoint (Farlow et al. 1995; Holtz 2004) and the published growth curve for T. rex is based on midshaft femoral measurements (Erickson et al. 2004), it is possible to quantitatively compare the published growth curve for T. rex with the growth pattern observed in this specimen. Measuring the midpoint of each growth line to an accuracy of ± 0.5 mm along a radial transect, T. rex annual growth markers are exceptionally good predictors for the growth lines observed in this bone (cχ2 = 1.44, df = 6, p-value > 0.95). As T. rex is the only animal known to exhibit this characteristic pattern of growth (Erickson et al. 2004; ChinsamyTuran 2005), this is believed to be a fairly powerful diagnostic test. Significance—Estimated to be about 71 m.y. old based on the age of the Baculites eliasi ammonite zone, these fossils may be among the oldest known T. rex fossils (D. Wolberg, pers. comm. 2007). Institutional abbreviation—TSJC, Trinidad State Junior College Louden-Henritze Archeology Museum.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71173870","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}
Updated age assignments and new collections of molluscan fossils from lower Cenomanian through upper Campanian strata in Texas permit a much refined biostratigraphic correlation with the rocks of New Mexico and the Western Interior. Generic names of many Late Cretaceous ammonites and inoceramid bivalves from Texas are updated to permit this correlation. Strata correlated in the west-to-east transect include the lower Cenomanian Beartooth Quartzite and Sarten Sandstone of southwest New Mexico, and the Eagle Mountains Formation, Del Rio Clay, Buda Limestone, and basal beds of the Chispa Summit, Ojinaga, and Boquillas Formations of the Texas–Mexico border area. Middle Cenomanian strata are lacking in southwestern New Mexico but are present in the lower parts of the Chispa Summit and Boquillas Formations in southwest Texas. Upper Cenomanian and lower Turonian rocks are present at many localities in New Mexico and Texas in the Mancos Shale and Chispa Summit, Ojinaga, and Boquillas Formations. Middle Turonian and younger rocks seem to be entirely nonmarine in southwestern New Mexico, but they are marine in the Rio Grande area in the Chispa Summit, Ojinaga, and Boquillas Formations. The upper part of the Chispa Summit and Boquillas contain late Turonian fossils. Rocks of Coniacian and Santonian age are present high in the Chispa Summit, Ojinaga, and Boquillas Formations, and in the lower part of the Austin. The San Carlos, Aguja, Pen, and Austin Formations contain fossils of Campanian age. Fossils representing at least 38 Upper Cretaceous ammonite zones are present along the transect. Collections made in recent years in southwestern New Mexico and at Sierra de Cristo Rey just west of downtown El Paso, Texas, have been well treated and do not need revision. Taxonomic names and zonations published in the pre-1970 literature on the Rio Grande area of Texas have been updated. New fossil collections from the Big Bend National Park, Texas, allow for a much refined correlation in the central part of the transect in Texas. Middle Turonian–Campanian zonation in southwest Texas is based mainly on ammonites of the Family Collignoniceratidae, as opposed to the scaphitid and baculitid ammonites that are especially abundant farther north in the Western Interior.
{"title":"Upper Cretaceous molluscan record along a transect from Virden, New Mexico, to Del Rio, Texas","authors":"W. A. Cobban, S. Hook, K. C. McKinney","doi":"10.58799/nmg-v30n3.75","DOIUrl":"https://doi.org/10.58799/nmg-v30n3.75","url":null,"abstract":"Updated age assignments and new collections of molluscan fossils from lower Cenomanian through upper Campanian strata in Texas permit a much refined biostratigraphic correlation with the rocks of New Mexico and the Western Interior. Generic names of many Late Cretaceous ammonites and inoceramid bivalves from Texas are updated to permit this correlation. Strata correlated in the west-to-east transect include the lower Cenomanian Beartooth Quartzite and Sarten Sandstone of southwest New Mexico, and the Eagle Mountains Formation, Del Rio Clay, Buda Limestone, and basal beds of the Chispa Summit, Ojinaga, and Boquillas Formations of the Texas–Mexico border area. Middle Cenomanian strata are lacking in southwestern New Mexico but are present in the lower parts of the Chispa Summit and Boquillas Formations in southwest Texas. Upper Cenomanian and lower Turonian rocks are present at many localities in New Mexico and Texas in the Mancos Shale and Chispa Summit, Ojinaga, and Boquillas Formations. Middle Turonian and younger rocks seem to be entirely nonmarine in southwestern New Mexico, but they are marine in the Rio Grande area in the Chispa Summit, Ojinaga, and Boquillas Formations. The upper part of the Chispa Summit and Boquillas contain late Turonian fossils. Rocks of Coniacian and Santonian age are present high in the Chispa Summit, Ojinaga, and Boquillas Formations, and in the lower part of the Austin. The San Carlos, Aguja, Pen, and Austin Formations contain fossils of Campanian age. Fossils representing at least 38 Upper Cretaceous ammonite zones are present along the transect. Collections made in recent years in southwestern New Mexico and at Sierra de Cristo Rey just west of downtown El Paso, Texas, have been well treated and do not need revision. Taxonomic names and zonations published in the pre-1970 literature on the Rio Grande area of Texas have been updated. New fossil collections from the Big Bend National Park, Texas, allow for a much refined correlation in the central part of the transect in Texas. Middle Turonian–Campanian zonation in southwest Texas is based mainly on ammonites of the Family Collignoniceratidae, as opposed to the scaphitid and baculitid ammonites that are especially abundant farther north in the Western Interior.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71174130","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}
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