{"title":"In Memory of Lee A. Woodward, 1931�2020","authors":"B. Kues","doi":"10.58799/nmg-v42n2.85","DOIUrl":"https://doi.org/10.58799/nmg-v42n2.85","url":null,"abstract":"","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71179084","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}
Upper Cretaceous sedimentary rocks are exposed in central Sierra County, southern New Mexico, in the Fra Cristobal Mountains, Caballo Mountains and in the topographically low Cutter sag between the two ranges. The ~2.5 km thick Cretaceous section is assigned to the (ascending order) Dakota Formation (locally includes the Oak Canyon [?] and Paguate [?] members), lower interval of the Mancos Formation (Graneros, Greenhorn, and Carlile members), Tres Hermanos Formation (Atarque, Campana, and Fite Ranch members), D-Cross Member of the Mancos Formation, Gallup Formation, Flying Eagle Canyon Formation, Ash Canyon Formation, and the McRae Group, consisting of the José Creek, Hall Lake, and Double Canyon formations. The name Tokay Tongue of the Mancos Formation is abandoned as an unnecessary term that reduces lithostratigraphic precision. The new name Campana Member of the Tres Hermanos Formation is proposed to replace the preoccupied (duplicate) name, Carthage Member. The terms Mesaverde Formation (Group) and Crevasse Canyon Formation are no longer applied to part of the Cretaceous section in Sierra County. Instead, these strata are the Flying Eagle Canyon Formation (new name) and redefined Ash Canyon Formation. The very thick McRae Formation is raised in rank to the McRae Group, and its constituent members are raised to formations. The Double Canyon Formation is a new lithostratigraphic unit comprising the upper part of the McRae Group. Ammonite and inoceramid bivalve biostratigraphy indicates that the lower interval of the Mancos Formation is of middle Cenomanian-early Turonian age, the Atarque Member of the Tres Hermanos Formation is early Turonian, the D-Cross Member of the Mancos Formation is middle Turonian, and the Gallup Formation is late Turonian. Vertebrate biostratigraphy indicates that the lower part of the Hall Lake Formation is Lancian (late Maastrichtian) in age. Depositional environments of the Cretaceous strata in Sierra County are both marine and nonmarine. They range from offshore marine (lower interval and D-Cross Member of the Mancos Formation), to shoreline deposition of various types (part of the Dakota Formation, the Atarque and Fite Ranch members of the Tres Hermanos Formation, and the Gallup Formation), to nonmarine fluvial channel and floodplain deposits (part of the Dakota Formation, Campana Member of the Tres Hermanos Formation, Flying Eagle Canyon Formation, Ash Canyon Formation, and the entire McRae Group). A comprehensive understanding of the Cretaceous strata in Sierra County allows a more detailed interpretation of local geologic events in the context of broad, transgressive-regressive (T-R) cycles of deposition in the Western Interior Seaway, and also in terms of Laramide orogenic history: (1) T1 transgression of the seaway during middle-late Cenomanian time resulting in deposition of the Dakota Formation, Graneros Member of the Mancos Formation and Greenhorn Member of the Mancos; (2) Turonian R1 regression with deposi
{"title":"The Cretaceous System in central Sierra County, New Mexico","authors":"S. Lucas, W. Nelson, K. Krainer, Scott D. Elrick","doi":"10.58799/nmg-v41n1.3","DOIUrl":"https://doi.org/10.58799/nmg-v41n1.3","url":null,"abstract":"Upper Cretaceous sedimentary rocks are exposed in central Sierra County, southern New Mexico, in the Fra Cristobal Mountains, Caballo Mountains and in the topographically low Cutter sag between the two ranges. The ~2.5 km thick Cretaceous section is assigned to the (ascending order) Dakota Formation (locally includes the Oak Canyon [?] and Paguate [?] members), lower interval of the Mancos Formation (Graneros, Greenhorn, and Carlile members), Tres Hermanos Formation (Atarque, Campana, and Fite Ranch members), D-Cross Member of the Mancos Formation, Gallup Formation, Flying Eagle Canyon Formation, Ash Canyon Formation, and the McRae Group, consisting of the José Creek, Hall Lake, and Double Canyon formations. The name Tokay Tongue of the Mancos Formation is abandoned as an unnecessary term that reduces lithostratigraphic precision. The new name Campana Member of the Tres Hermanos Formation is proposed to replace the preoccupied (duplicate) name, Carthage Member. The terms Mesaverde Formation (Group) and Crevasse Canyon Formation are no longer applied to part of the Cretaceous section in Sierra County. Instead, these strata are the Flying Eagle Canyon Formation (new name) and redefined Ash Canyon Formation. The very thick McRae Formation is raised in rank to the McRae Group, and its constituent members are raised to formations. The Double Canyon Formation is a new lithostratigraphic unit comprising the upper part of the McRae Group. Ammonite and inoceramid bivalve biostratigraphy indicates that the lower interval of the Mancos Formation is of middle Cenomanian-early Turonian age, the Atarque Member of the Tres Hermanos Formation is early Turonian, the D-Cross Member of the Mancos Formation is middle Turonian, and the Gallup Formation is late Turonian. Vertebrate biostratigraphy indicates that the lower part of the Hall Lake Formation is Lancian (late Maastrichtian) in age. Depositional environments of the Cretaceous strata in Sierra County are both marine and nonmarine. They range from offshore marine (lower interval and D-Cross Member of the Mancos Formation), to shoreline deposition of various types (part of the Dakota Formation, the Atarque and Fite Ranch members of the Tres Hermanos Formation, and the Gallup Formation), to nonmarine fluvial channel and floodplain deposits (part of the Dakota Formation, Campana Member of the Tres Hermanos Formation, Flying Eagle Canyon Formation, Ash Canyon Formation, and the entire McRae Group). A comprehensive understanding of the Cretaceous strata in Sierra County allows a more detailed interpretation of local geologic events in the context of broad, transgressive-regressive (T-R) cycles of deposition in the Western Interior Seaway, and also in terms of Laramide orogenic history: (1) T1 transgression of the seaway during middle-late Cenomanian time resulting in deposition of the Dakota Formation, Graneros Member of the Mancos Formation and Greenhorn Member of the Mancos; (2) Turonian R1 regression with deposi","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178940","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}
Spring 2019, Volume 41, Number 1 New Mexico Geology Many trace makers are also specific to a particular type of habitat, and this specificity provides an important tool in identifying and interpreting ancient environments. One environmentally diagnostic trace fossil is the burrow Ophiomorpha, which indicates littoral to shallow-marine paleoenvironments (Buatois and Mángano, 2011). Thus, Ophiomorpha are found in virtually all of the shallow-marine or shoreline Upper Cretaceous Trace fossils are structures in sedimentary rocks that record the interaction of organisms with sediment. Often thought of as “fossilized behavior,” trace fossils are important archives of the activities of extinct plants and animals. Many trace fossils are also strong indicators of paleoenvironments, an observation that underlies the concept of ichnofacies. This is in part because specific organismal behaviors are often correlated with particular substrates. Gallery of Geology
许多痕迹制造者也专门针对特定类型的栖息地，这种特殊性为识别和解释古代环境提供了重要工具。一个环境诊断的痕迹化石是洞穴蛇形虫，它表明了沿海到浅海的古环境(Buatois and Mángano, 2011)。因此，在上白垩纪几乎所有的浅海或海岸线上都发现了蛇形生物。痕迹化石是沉积岩中的结构，记录了生物与沉积物的相互作用。痕迹化石通常被认为是“行为化石”，是已灭绝动植物活动的重要档案。许多痕迹化石也是古环境的有力指标，这一观察结果奠定了岩相概念的基础。这部分是因为特定的生物行为通常与特定的基质相关。地质展览馆
{"title":"Gallery of Geology: The trace fossil Ophiomorpha from the Upper Cretaceous Trinidad Sandstone, northeastern New Mexico","authors":"S. Lucas","doi":"10.58799/nmg-v41n1.40","DOIUrl":"https://doi.org/10.58799/nmg-v41n1.40","url":null,"abstract":"Spring 2019, Volume 41, Number 1 New Mexico Geology Many trace makers are also specific to a particular type of habitat, and this specificity provides an important tool in identifying and interpreting ancient environments. One environmentally diagnostic trace fossil is the burrow Ophiomorpha, which indicates littoral to shallow-marine paleoenvironments (Buatois and Mángano, 2011). Thus, Ophiomorpha are found in virtually all of the shallow-marine or shoreline Upper Cretaceous Trace fossils are structures in sedimentary rocks that record the interaction of organisms with sediment. Often thought of as “fossilized behavior,” trace fossils are important archives of the activities of extinct plants and animals. Many trace fossils are also strong indicators of paleoenvironments, an observation that underlies the concept of ichnofacies. This is in part because specific organismal behaviors are often correlated with particular substrates. Gallery of Geology","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71179288","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}
The Pierre Shale is a marine deposit that accumulated in the Cretaceous Western Interior Seaway during the onset of Laramide tectonism in the southern Rocky Mountains region. In the eastern part of the Raton Basin near Trinidad, Colorado, ammonite biostratigraphy suggests that the base of the Pierre Shale lies within or slightly above the Lower Campanian Scaphites hippocrepis III ammonite range zone (81.8–80.5 Ma), and the top of the Pierre Shale corresponds with the Lower Maastrichtian Baculites clinolobatus Zone (69.59 + 0.36 Ma). These data are consistent with previous estimates for the age of the base of the Pierre Shale in the Raton Basin, and indicate that the top of the Pierre Shale (base of the overlying Trinidad Sandstone) in the eastern part of the basin lies near the Lower-Upper Maastrichtian substage boundary. A Late Maastrichtian age for the Trinidad Sandstone near Trinidad has a bearing on the timing of geological events associated with the eastward retreat of the Western Interior Seaway from the region during the Late Cretaceous. Introduction The Pierre Shale was deposited within the Western Interior Seaway during an early phase of Laramide tectonism, which resulted in areas of regional subsidence and uplift associated with subduction of the Farallon tectonic plate beneath western North America (Baltz, 1965; Cather, 2004; Slattery et al., 2015; Heller and Liu, 2016). In the Raton Basin of northeastern New Mexico and south-central Colorado (Fig.1), the Pierre Shale is underlain by the Niobrara Formation and overlain by the Trinidad Sandstone (Lee, 1917). The age of the base of the Pierre Shale is constrained by ammonite biostratigraphy of the uppermost part of the Niobrara Formation in the Raton Basin and surrounding regions (Scott et al., 1986; Molenaar et al., 2002; Merewether et al., 2011). The age of the top of the Pierre Shale is similarly constrained by ammonite biostratigraphy of the upper part of the formation.
皮埃尔页岩是南落基山脉地区Laramide构造运动开始时沉积于白垩系西部内陆海道的海相沉积。在科罗拉多州特立尼达附近的Raton盆地东部，皮埃尔页岩的底部位于下坎帕尼亚scapites hippocrepis III型鹦鹉螺岩范围带(81.8 ~ 80.5 Ma)内或略高于该范围带，皮埃尔页岩的顶部对应于下马斯垂Baculites clinolobatus带(69.59 + 0.36 Ma)。这些数据与以往对Raton盆地Pierre页岩基底年龄的估计一致，表明盆地东部Pierre页岩的顶部(上覆特立尼达砂岩的基底)位于上马斯特里赫特下部亚阶段边界附近。特立尼达附近特立尼达砂岩的晚马斯特里赫特时代与晚白垩纪西部内陆海道向东撤退有关的地质事件的时间有关。Pierre页岩沉积于Laramide构造运动早期的西部内陆海道内，该构造运动导致了与Farallon构造板块俯冲相关的区域沉陷和隆起(Baltz, 1965;凯瑟,2004;Slattery等，2015;Heller and Liu, 2016)。在新墨西哥州东北部和科罗拉多州中南部的Raton盆地(图1)，Pierre页岩下部为Niobrara组，上覆为Trinidad砂岩(Lee, 1917)。Pierre页岩基底的年龄受Raton盆地及周边地区Niobrara组最上部的鹦鹉螺生物地层的限制(Scott et al.， 1986;Molenaar et al.， 2002;Merewether et al.， 2011)。皮埃尔页岩顶部的年龄同样受到地层上部菊石生物地层学的限制。
{"title":"Baculites (Ammonoidea) and the age of the Pierre Shale in the eastern Raton Basin, south-central Colorado","authors":"K. Berry","doi":"10.58799/nmg-v40n1.1","DOIUrl":"https://doi.org/10.58799/nmg-v40n1.1","url":null,"abstract":"The Pierre Shale is a marine deposit that accumulated in the Cretaceous Western Interior Seaway during the onset of Laramide tectonism in the southern Rocky Mountains region. In the eastern part of the Raton Basin near Trinidad, Colorado, ammonite biostratigraphy suggests that the base of the Pierre Shale lies within or slightly above the Lower Campanian Scaphites hippocrepis III ammonite range zone (81.8–80.5 Ma), and the top of the Pierre Shale corresponds with the Lower Maastrichtian Baculites clinolobatus Zone (69.59 + 0.36 Ma). These data are consistent with previous estimates for the age of the base of the Pierre Shale in the Raton Basin, and indicate that the top of the Pierre Shale (base of the overlying Trinidad Sandstone) in the eastern part of the basin lies near the Lower-Upper Maastrichtian substage boundary. A Late Maastrichtian age for the Trinidad Sandstone near Trinidad has a bearing on the timing of geological events associated with the eastward retreat of the Western Interior Seaway from the region during the Late Cretaceous. Introduction The Pierre Shale was deposited within the Western Interior Seaway during an early phase of Laramide tectonism, which resulted in areas of regional subsidence and uplift associated with subduction of the Farallon tectonic plate beneath western North America (Baltz, 1965; Cather, 2004; Slattery et al., 2015; Heller and Liu, 2016). In the Raton Basin of northeastern New Mexico and south-central Colorado (Fig.1), the Pierre Shale is underlain by the Niobrara Formation and overlain by the Trinidad Sandstone (Lee, 1917). The age of the base of the Pierre Shale is constrained by ammonite biostratigraphy of the uppermost part of the Niobrara Formation in the Raton Basin and surrounding regions (Scott et al., 1986; Molenaar et al., 2002; Merewether et al., 2011). The age of the top of the Pierre Shale is similarly constrained by ammonite biostratigraphy of the upper part of the formation.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178837","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 Late Pennsylvanian (Missourian) index fusulinid Eowaeringella in the Manzanita Mountains of central New Mexico","authors":"B. Allen, S. Lucas","doi":"10.58799/nmg-v40n2.35","DOIUrl":"https://doi.org/10.58799/nmg-v40n2.35","url":null,"abstract":"","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178702","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}
New Mexico Geology (NMG) publishes peer-reviewed geoscience papers focusing on New Mexico and the surrounding region. We aslo welcome submissions to the Gallery of Geology
{"title":"Sorting clasts across laminated maar dunes, Kilbourne and Hunts Holes, New Mexico: comparisons to sorting across aeolian and fluvial bedforms","authors":"D. Love, A. Gutjahr, Andreas G. Lazari","doi":"10.58799/nmg-v40n2.45","DOIUrl":"https://doi.org/10.58799/nmg-v40n2.45","url":null,"abstract":"New Mexico Geology (NMG) publishes peer-reviewed geoscience papers focusing on New Mexico and the surrounding region. We aslo welcome submissions to the Gallery of Geology","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178763","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}
The Bursum Formation of latest Pennsylvanian age was deposited during the final episode of the Ancestral Rocky Mountains deformation in central New Mexico. Over 600 paleocurrent measurements were collected from fluvial strata of the Bursum Formation in the Quebradas region east of Socorro. These measurements, in concert with data from the Bursum Formation for thickness (from outcrops and wells), lithofacies distribution, and maximum clast size provide new constraints on the paleotectonic framework during the Late Pennsylvanian. The long-known Joyita Uplift supplied detritus, mostly recycled from older Pennsylvanian strata, to the northern part of the study area. A major source region exposing dominantly Proterozoic rocks, herein termed the San Antonio Uplift, existed in what is now the southern part of the Socorro Basin of the Rio Grande rift. The San Antonio Uplift contributed arkosic detritus to the central and southern parts of the study area. These two uplifts dominated sediment supply to the western part of a broad region in which the Bursum Formation gradually thickens to the southeast, toward the Pedernal Uplift near Carrizozo. This region formed a weakly subsided saddle-shaped platform between the deep Estancia and Pedernal basins to the north and south. It was not a narrow, symmetrical basin as depicted in previous studies.
{"title":"Revised basin geometry for the Bursum Formation (upper Virgilian-lower Wolfcampian), central New Mexico","authors":"S. Cather","doi":"10.58799/nmg-v40n1.6","DOIUrl":"https://doi.org/10.58799/nmg-v40n1.6","url":null,"abstract":"The Bursum Formation of latest Pennsylvanian age was deposited during the final episode of the Ancestral Rocky Mountains deformation in central New Mexico. Over 600 paleocurrent measurements were collected from fluvial strata of the Bursum Formation in the Quebradas region east of Socorro. These measurements, in concert with data from the Bursum Formation for thickness (from outcrops and wells), lithofacies distribution, and maximum clast size provide new constraints on the paleotectonic framework during the Late Pennsylvanian. The long-known Joyita Uplift supplied detritus, mostly recycled from older Pennsylvanian strata, to the northern part of the study area. A major source region exposing dominantly Proterozoic rocks, herein termed the San Antonio Uplift, existed in what is now the southern part of the Socorro Basin of the Rio Grande rift. The San Antonio Uplift contributed arkosic detritus to the central and southern parts of the study area. These two uplifts dominated sediment supply to the western part of a broad region in which the Bursum Formation gradually thickens to the southeast, toward the Pedernal Uplift near Carrizozo. This region formed a weakly subsided saddle-shaped platform between the deep Estancia and Pedernal basins to the north and south. It was not a narrow, symmetrical basin as depicted in previous studies.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178496","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":"Reassessment of features in the Aden Crater lava flows, Do�a Ana County, New Mexico","authors":"R. A. De Hon, R. Earl","doi":"10.58799/nmg-v40n1.17","DOIUrl":"https://doi.org/10.58799/nmg-v40n1.17","url":null,"abstract":"","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178889","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, R. Hulbert, E. S. Gottlieb, J. Amato, G. Mack, T. Jonell
A mandible of a tapir (Tapirus sp.) from the late Pliocene (early Blancan North American land mammal age-NALMA), Tonuco Mountain Local Fauna (LF), Dona Ana County, southern New Mexico, is a significant addition to the small sample of fossil tapirs known from the late Cenozoic of New Mexico. The Tonuco Mountain tapir mandible is not identified to the species level because the diagnostic characters in the genus Tapirus are primarily found in the skull. It is most similar in size and morphological features to the mandible of the late Blancan species Tapirus lundeliusi from Florida. The Tonuco Mountain LF consists of 17 species of vertebrates, including a mud turtle, two tortoises, a duck, and 13 species of mammals. Among mammals in this fauna, the camel Camelops, the peccary Platygonus, and the horse Equus scotti first appeared in North American early Blancan faunas at about 3.6 Ma, whereas the horses Nannippus peninsulatus and Equus simplicidens became extinct in New Mexico in the late Blancan at about 2.6 Ma. The association of these mammals, together with the absence of mammals of South American origin that first appeared in the American Southwest at about 2.7 Ma, restricts the age of the Tonuco Mountain LF to the late early Blancan, between 2.7 and 3.6 Ma. The fossils from the Tonuco Mountain LF are derived from sediments of the axial-fluvial lithofacies of the ancestral Rio Grande, referred to the Camp Rice Formation. The sediments in the lower 30 m of the Camp Rice Formation section containing the Tonuco Mountain LF, including the Tapirus mandible, are normally magnetized and correspond to the lowermost portion of the Gauss Chron (C2An.3n), above the Gilbert/Gauss boundary (younger than 3.58 Ma) and below the base of the Mammoth Subchron (C2An.2r; older than 3.33 Ma). The mammalian biochronology and magnetostratigraphy restrict the age of the Tonuco Mountain LF to between 3.3 and 3.6 Ma (early late Pliocene, late early Blancan). The tapir mandible from the Tonuco Mountain LF is the first record of Tapirus from the early Blancan (2.7-4.9 Ma) of North America. Tapirus had a restricted geographic distribution in the late Pliocene and earliest Pleistocene (late early and late Blancan; ~1.6-3.6 Ma) of temperate North America, occurring primarily in the southern United States from Florida to California, including New Mexico.
{"title":"The tapir Tapirus (Mammalia: Perissodactyla) from the late Pliocene (early Blancan) Tonuco Mountain Local Fauna, Camp Rice Formation, Do�a Ana County, southern New Mexico","authors":"G. Morgan, R. Hulbert, E. S. Gottlieb, J. Amato, G. Mack, T. Jonell","doi":"10.58799/nmg-v39n2.28","DOIUrl":"https://doi.org/10.58799/nmg-v39n2.28","url":null,"abstract":"A mandible of a tapir (Tapirus sp.) from the late Pliocene (early Blancan North American land mammal age-NALMA), Tonuco Mountain Local Fauna (LF), Dona Ana County, southern New Mexico, is a significant addition to the small sample of fossil tapirs known from the late Cenozoic of New Mexico. The Tonuco Mountain tapir mandible is not identified to the species level because the diagnostic characters in the genus Tapirus are primarily found in the skull. It is most similar in size and morphological features to the mandible of the late Blancan species Tapirus lundeliusi from Florida. The Tonuco Mountain LF consists of 17 species of vertebrates, including a mud turtle, two tortoises, a duck, and 13 species of mammals. Among mammals in this fauna, the camel Camelops, the peccary Platygonus, and the horse Equus scotti first appeared in North American early Blancan faunas at about 3.6 Ma, whereas the horses Nannippus peninsulatus and Equus simplicidens became extinct in New Mexico in the late Blancan at about 2.6 Ma. The association of these mammals, together with the absence of mammals of South American origin that first appeared in the American Southwest at about 2.7 Ma, restricts the age of the Tonuco Mountain LF to the late early Blancan, between 2.7 and 3.6 Ma. The fossils from the Tonuco Mountain LF are derived from sediments of the axial-fluvial lithofacies of the ancestral Rio Grande, referred to the Camp Rice Formation. The sediments in the lower 30 m of the Camp Rice Formation section containing the Tonuco Mountain LF, including the Tapirus mandible, are normally magnetized and correspond to the lowermost portion of the Gauss Chron (C2An.3n), above the Gilbert/Gauss boundary (younger than 3.58 Ma) and below the base of the Mammoth Subchron (C2An.2r; older than 3.33 Ma). The mammalian biochronology and magnetostratigraphy restrict the age of the Tonuco Mountain LF to between 3.3 and 3.6 Ma (early late Pliocene, late early Blancan). The tapir mandible from the Tonuco Mountain LF is the first record of Tapirus from the early Blancan (2.7-4.9 Ma) of North America. Tapirus had a restricted geographic distribution in the late Pliocene and earliest Pleistocene (late early and late Blancan; ~1.6-3.6 Ma) of temperate North America, occurring primarily in the southern United States from Florida to California, including New Mexico.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42130686","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}
Katie Zemlick, B. Thomson, Janie M. Chermak, V. Tidwell
New Mexico was at the forefront of the nuclear age, producing more uranium (U) than any other state in the U.S. for more than three decades until the early 1980s. The state is also unique because these historic activities have been studied and quantified over during this time, providing a unique opportunity to identify how historic uranium mining operations were influenced by economics and policy. In order to quantify these relationships, this study used a system dynamics approach to determine how these factors affected mining industry decisions and how those impacts varied based on mine size. The results of this work found that as the industry evolved over time, the influence of these factors changed and that they did not impact all mining operations equally. Results indicate that price guarantees for U concentrate and subsidies for mining and milling in the early years (1948–1964) of U mining encouraged mines of all size, although smaller mines opened and closed more quickly in response to changes in price. The economic environment created by these policies encouraged exploration and production. However, the latter led to an excess in supplies and declining prices when these incentives lapsed in the mid-1960s, which negatively impacted small- and medium-sized mines, neither of which opened after 1964. The presence of larger mines had more impact on the closing of small mines than closing of medium mines, possibly as a result of economies of scale for the medium mines or their ability to access milling resources after 1964. Lastly, medium and large mines that produced both uranium and vanadium may have had a slight historic advantage over mines that produced only uranium, as evidenced by longer delays in closing response to a unit change in average price. Quantification of these relationships assists in an improved understanding of the factors that influenced historic mining operational decisions and illustrates the complexity of the roles played by economics and policies in the boom and bust cycle manifested in the uranium industry.
{"title":"Modeled Impacts of Economics and Policy on Historic Uranium Mining Operations in New Mexico","authors":"Katie Zemlick, B. Thomson, Janie M. Chermak, V. Tidwell","doi":"10.58799/nmg-v39n1.11","DOIUrl":"https://doi.org/10.58799/nmg-v39n1.11","url":null,"abstract":"New Mexico was at the forefront of the nuclear age, producing more uranium (U) than any other state in the U.S. for more than three decades until the early 1980s. The state is also unique because these historic activities have been studied and quantified over during this time, providing a unique opportunity to identify how historic uranium mining operations were influenced by economics and policy. In order to quantify these relationships, this study used a system dynamics approach to determine how these factors affected mining industry decisions and how those impacts varied based on mine size. The results of this work found that as the industry evolved over time, the influence of these factors changed and that they did not impact all mining operations equally. Results indicate that price guarantees for U concentrate and subsidies for mining and milling in the early years (1948–1964) of U mining encouraged mines of all size, although smaller mines opened and closed more quickly in response to changes in price. The economic environment created by these policies encouraged exploration and production. However, the latter led to an excess in supplies and declining prices when these incentives lapsed in the mid-1960s, which negatively impacted small- and medium-sized mines, neither of which opened after 1964. The presence of larger mines had more impact on the closing of small mines than closing of medium mines, possibly as a result of economies of scale for the medium mines or their ability to access milling resources after 1964. Lastly, medium and large mines that produced both uranium and vanadium may have had a slight historic advantage over mines that produced only uranium, as evidenced by longer delays in closing response to a unit change in average price. Quantification of these relationships assists in an improved understanding of the factors that influenced historic mining operational decisions and illustrates the complexity of the roles played by economics and policies in the boom and bust cycle manifested in the uranium industry.","PeriodicalId":35824,"journal":{"name":"New Mexico Geology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71178412","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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