Las Cruces Country III最新文献

{"title":"A new stegomastodon skull (Proboscidea: Gomphotheriidai) from the Camp Rice Formation, Do�a Ana County, New Mexico","authors":"P. Houde, D. Peltier","doi":"10.56577/ffc-69.53","DOIUrl":"https://doi.org/10.56577/ffc-69.53","url":null,"abstract":"","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130596810","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 Aden lava flows, Do�a Ana County, New Mexico","authors":"R. Dehon, R. Earl","doi":"10.56577/ffc-69.197","DOIUrl":"https://doi.org/10.56577/ffc-69.197","url":null,"abstract":"Aden Crater is a small volcanic shield in the Potrillo Volcanic Field approximately 40 km southwest from Las Cruces. The shield and surrounding flow field are mapped as volcanic facies in which the morphology is governed by the rheology of the lava. The flow field which spreads east and south from the vent consist of early, fluid basalts that inflated to various thicknesses determined by the strength of the outer crust. Flows inflated to form steep-margined, flat-topped plateaus. The field is a rugged accumulation of inflation plateaus in which adjacent flow margins form deep intervening ravines. The Aden shield was formed as viscosity increased to the point that the lavas began to accumulate over the vent. The shield facies consist of basal thin scabby flows, very low sloping lobate flows, and an upper slope of steeper channeled flows, with a wide shallow crater at the top. 197","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"262 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":"115013299","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":"Summary of landforms of the central Jornada del Muerto that influence the hydrology and path of El Camino Real de Tierra Adentro","authors":"D. Kludt, D. Love, T. Newton, B. Allen","doi":"10.56577/ffc-69.57","DOIUrl":"https://doi.org/10.56577/ffc-69.57","url":null,"abstract":"","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","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":"130487049","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":"Age relationships of igneous rocks in the Do�a Ana Mountains","authors":"F. Ramos, M. Heizler","doi":"10.56577/ffc-69.159","DOIUrl":"https://doi.org/10.56577/ffc-69.159","url":null,"abstract":"A bstrAct — Igneous rocks in the Doña Ana Mountains encompass ages that range from at least 43.1 to 33.2 Ma. Rocks of the Palm Park formation are ~43 Ma and are intruded by younger Doña Ana Rhyolite at 36 Ma. Rhyolite of nearby Goat Mountain is of similar age but different composition. Regional dikes, likely related to the Summerford Syenite Sill, are ~33 Ma and significantly post-date Doña Ana and Goat Mountain rhyolitic volcanism. These dikes have different compositions compared to the Doña Ana Rhyolite and are emplaced after the formation of the Doña Ana caldera.","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"7 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":"127902215","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":"Early Pliocene paleovalley incision during early Rio Grande evolution in southern New Mexico","authors":"D. Koning, A. Jochems, M. Heizler","doi":"10.56577/ffc-69.93","DOIUrl":"https://doi.org/10.56577/ffc-69.93","url":null,"abstract":"Stratigraphic relations in the Truth or Consequences area indicate that the early Rio Grande incised and backfilled twice over 0.6 my, forming two 20-m-deep paleovalleys, shortly after this paleoriver propagated into southern New Mexico. Paleovalley incision is recognized by buttress unconformities between different-aged, lithologically distinctive axial and piedmont deposits. Older (pre-paleovalley) deposits correlate to the Palomas Formation basal transitional unit (map unit Tplt), which includes western-derived piedmont deposits and some of the earliest Rio Grande deposits in the Palomas and Engle Basins. The first (older) paleovalley was backfilled with axial-fluvial sediment consisting of a coarse-grained, basal conglomerate overlain by sandstone and pebbly sandstone; all gravel was locally derived from highlands surrounding the Engle Basin. The second paleovalley fill is distinctive because it contains extrabasinal, coarser (cobble-rich) conglomerate. To the west, the top of the Tplt unit is overlain by coarser-grained and lesser cemented piedmont deposits of the Palomas Formation. These volcaniclastic deposits interfinger eastward with axial-fluvial deposits overlying both aforementioned paleovalleys; these younger axial-fluvial deposits are composed of sand with 5–20% pebbly beds that lack extrabasinal gravel. Radiometric dating of basalt clasts and cryptomelane provide age control for paleovalley formation. A basalt clast dated at 5.06±0.02 Ma (40Ar/39Ar age), collected ~4 m below the top of Tplt, provides a maximum age for both the top of this unit and incision of the older paleovalley. Cryptomelane precipitated at the top of the older paleovalley fill is 4.87±0.05 (previously published 40Ar/39Ar age). Thus, incision and back-filling of the first paleovalley happened between 5.1 and 4.87 Ma , and incision of the second, nested paleovalley occurred after 4.87 Ma. A basalt cobble collected 6 m above the base of the coarse-grained, lesser-cemented piedmont deposits returned an 40Ar/39Ar age of 4.49±0.03 Ma. This stratigraphic horizon projects to 10–12 m above the base of the younger axial-fluvial unit that overlies the second paleovalley; the horizon also underlies (by at least 15 m) the ~3.6–3.3 Ma Repenning fossil site. Thus, aggradation of the second paleovalley continued to ca. 4.5 Ma. The relatively quick succession of two ~20-m-deep incision/backfilling events within 0.6 my, each incising to a similar base level, suggests a paleoclimatic driver that caused notable fluctuations in sediment-water discharge ratios similar to later Pleistocene events. We propose that a similar buried paleovalley may exist between the Palomas and Mesilla Basins, which might explain the general lack of pre-3.6 Ma axial-fluvial deposits in that region. 93","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"83 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":"126290730","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":"U-Pb geochronology of Proterozoic igneous and metasedimentary rocks in southern New Mexico: Post-collisional S-type granite magmatism","authors":"J. Amato, C. Ottenfeld, C. Howland","doi":"10.56577/ffc-69.137","DOIUrl":"https://doi.org/10.56577/ffc-69.137","url":null,"abstract":"A bstract — U-Pb zircon ages, major element geochemistry, and Nd isotopic data are presented from several localities in the southern part of the Proterozoic Mazatzal province of southern New Mexico, excluding the Burro and San Andres Mountains. These data indicate that the bulk of granitic magmatism in the study area occurred at 1655 Ma, and that the granites are largely undeformed or only locally deformed. This group of igneous rocks is statistically younger than ~1675 Ma orthogneisses, indicating that a regional deformational event occurred between 1675–1655 Ma. The 1655 Ma granites are leucocratic with high SiO 2 and Al 2 O 3 and low MgO, have both biotite and muscovite, and thus are S-type granites. Nd isotopic compositions of three samples ranges from ε Nd = 1.1 to –2.0, but no useful mantle model ages were obtained owing to Sm/Nd modification after crystallization. We present a model for their generation as crustal melts following a collision. Our data also show that 1460 Ma plutons are present in the Fra Cristobal Range, Organ Mts., Antelope Hill in the southern San Andres Mountains, and likely at San Diego Mountain. This even was accompanied by metamorphism as indicated by younger zircon growth in granites at Cookes Peak and by metamorphic titanite growth at Mud Mountain. These new ages provide additional information regarding the development of the southern Mazatzal province.","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"360 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":"123782508","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":"Fusulinid and Conodont biostratigraphy of the Beeman formation (Pennsylvanian), Sacramento Mountains, New Mexico","authors":"G. Wahlman, J. Barrick","doi":"10.56577/ffc-69.83","DOIUrl":"https://doi.org/10.56577/ffc-69.83","url":null,"abstract":"A bstrAct — Fusulinid and conodont biostratigraphic analyses date the Pennsylvanian Beeman Formation in the Sacramento Mountains of south-central New Mexico as early middle Missourian to the early to early middle Virgilian. Based on conodont data, the Desmoine-sian-Missourian boundary is in the uppermost part of the underlying Gobbler Formation, and based on fusulinid and conodont data, the Missourian-Virgilian boundary is in the upper part of the Beeman Formation.","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"40 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":"114625562","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":"40Ar/39Ar ages of Palm Park volcanic rocks, south-central New Mexico","authors":"F. Ramos, B.A. Heizler","doi":"10.56577/ffc-69.165","DOIUrl":"https://doi.org/10.56577/ffc-69.165","url":null,"abstract":"Volcanic rocks of the Palm Park Formation, exposed in multiple locations throughout south-central New Mexico, are composed of volcanic and volcanoclastic rocks that are lithologically and compositionally variable at scales within individual exposures and between exposures at different localities. 40Ar/39Ar ages of plagioclase and biotite from Palm Park volcanic rocks range from ~43.5 to ~39.5 Ma. These eruption ages can be used to correlate exposures throughout south-central New Mexico and are generally consistent with zircon ages from the same units. Overall, these ages constrain the timing of magmatism related to the Laramide Orogeny as it transitioned to magmatism associated with the ignimbrite flare-up. This is a poorly studied portion of the middle Tertiary magmatic history of southern New Mexico and Palm Park Formation volcanic units provide an excellent opportunity to refine our knowledge of the geologic history of this time interval. 165 INTRODUCTION Although the ages of late-Eocene, ignimbrite flare-up-related magmatism have been well documented in south-central New Mexico (e.g., Zimmerer and McIntosh, 2013; Verplanck et al., 1999; Ramos et al., this volume), little is known about the specific ages of middleto late-Eocene volcanism and volcaniclastic sedimentation that occurred just prior to this time period. Tectonically, the period encompasses the transition between Laramide orogenesis and the onset of late Eocene/ early Oligocene bimodal volcanism (prior to initiation of Rio Grande rifting in this region at ~36 Ma) and is reflected in the volcanic and volcaniclastic rocks of the Palm Park Formation. The Palm Park Formation in south-central New Mexico is composed of an agglomeration of lithologically variable volcanic rocks and volcanoclastic sedimentary rocks, mostly andesitic or dacitic in composition, that are scattered throughout the region. Although lavas within regional stratigraphic sections are local in nature, accompanying ash-fall deposits likely originate from more distal volcanic sources. Overall, these rocks are primarily andesites or dacites and are difficult to stratigraphically correlate across localities. The oldest exposed section of the Palm Park Formation is marked by a light-colored ash-fall tuff (PALMP(RB/AC)-02) in the Robledo Mountains (Seager et al., 2008) that yields a weighted-mean zircon age of 45.0±0.8 Ma (Creitz et al., this volume). This ash-fall tuff is present in Palm Park strata but may originate from a more distal source and not reflect the same local magmatic sources as most Palm Park Formation volcanic rocks (Ramos et al., this volume). Similarly, the youngest section of the Palm Park Formation is defined by an ash fall tuff (PALMP(SU/BT)-01) in the uppermost Palm Park Formation in the Sierra de las Uvas Mountains that yields a weighted-mean zircon age of 39.6±0.5 Ma (Creitz et al., this volume). This tuff may also originate from a distal magmatic source (Ramos et al., this volume). Intervening stra","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"14 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":"128041510","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 Do�a Ana Caldera and regional outflow sheets: First-day Road Log from Las Cruces to Southern Do�a Ana Mountains and Point of Rocks","authors":"G. Mack, F. Ramos, B. Hampton, W. Seager, J. Witcher","doi":"10.56577/ffc-69.1","DOIUrl":"https://doi.org/10.56577/ffc-69.1","url":null,"abstract":"","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","volume":"18 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":"131716146","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":"Sr and Pb isotope variations of igneous feldspars in the Do�a Ana mountains","authors":"F. Ramos, T. Aşkın, S. Lévesque, P. Stevens, J. Thines, S. Farnsworth-Pinkerton, S. Lindell, N. Richard","doi":"10.56577/ffc-69.173","DOIUrl":"https://doi.org/10.56577/ffc-69.173","url":null,"abstract":"A bstrAct — Igneous rocks in the Doña Ana Mountains record a poorly studied portion of mid-Tertiary magmatism affecting southern New Mexico. Here, Sr and Pb isotopes of feldspars are used to evaluate the origins and potential magmatic relationships between compositional-ly variable igneous rocks. Overall, plagioclase, sanidine and orthoclase crystals from igneous rocks in the Doña Ana Mountains crystallized from magmas with very different Sr and Pb isotope characteristics. Plagioclase crystals from Early Eocene Palm Park Formation andesite and dacite have similar 87 Sr/ 86 Sr ratios but vary widely in 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb. These variations are consistent with the presence of variable magmatic sources that were not involved in Late-Eocene/Early Oligocene magmatism in the Doña Ana Mountains. Sanidine crystals from the Doña Ana Rhyolite and nearby Goat Mountain Rhyolite have similar 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb ratios but variable 87 Sr/ 86 Sr ratios, which precludes a simple petrogenetic relationship between them and which also confirms the presence of mul- tiple, highly-evolved magma compositions at ~36 Ma. Orthoclase crystals from syenite dikes that crosscut volcanic rocks in the Doña Ana Mountains, which were presumed to have been parental to the rhyolites, have different 206 Pb/ 204 Pb, and that undermine any direct magmatic connections between the syenite and rhyolites in the Doña Ana Mountains.","PeriodicalId":253436,"journal":{"name":"Las Cruces Country III","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":"128754647","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}