Geological Society of America Abstracts with Programs最新文献

{"title":"CONSTRAINING REDUCING CONDITIONS IN THE PRAGUE BASIN DURING THE LATE SILURIAN LAU/KOZLOWSKII EXTINCTION EVENT","authors":"Lindsi J. Allman, Chelsie N. Bowman, Jiří Frýda, Nevin P. Kozik, Jeremy Owens, Seth Young","doi":"10.1130/abs/2023am-392842","DOIUrl":"https://doi.org/10.1130/abs/2023am-392842","url":null,"abstract":"\u0000 The Silurian was marked by repeated extinctions, carbon cycle volatility, and significant intervals of climatic change. The most notable of these events were the Ludfordian Lau/Kozlowskii extinction and associated Mid-Ludfordian Lau carbon isotope excursion, both of which have been linked to a period of global cooling and expanded reducing conditions in the global oceans. Here we present new data that characterize marine paleoredox conditions of the Prague Basin, a peri-Gondwanan terrane. This study utilizes iodine-to-calcium ratios to assess local redox conditions in a shallow water carbonate succession and iron speciation and redox-sensitive trace element concentrations to assess local redox conditions of a deeper water sequence. Consistently low values of I/Ca in the shallow water section suggest either persistent local low oxygen conditions or possibly diagenetic overprinting. Iron speciation data suggest that bottom water redox conditions in the deeper shelf setting were consistently anoxic with possible intermittent euxinia. Concentrations of redox-sensitive trace elements consistently higher than upper continental crust values also indicate persistent reducing conditions in the deeper part of the basin. These local redox proxy data from the Prague Basin, including trends in new pyrite sulfur isotope (δ\u0000 34\u0000 S\u0000 pyr\u0000 ) data, are consistent with findings that expansion of anoxic and/or euxinic oceanic conditions occurred. These data, derived from a mid-paleolatitude marine setting, fill an important gap in our current global dataset from this interval of the late Silurian.\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the Chemical Evolution of the Mid-Paleozoic Earth System and Biotic Response collection available at:\u0000 https://www.lyellcollection.org/topic/collections/chemical-evolution-of-the-mid-paleozoic-earth-system\u0000 \u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.7008107\u0000","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"27 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139445188","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":"PALEOGEOGRAPHY AND HIGH-PRECISION GEOCHRONOLOGY OF THE NEOARCHEAN FORTESCUE GROUP, PILBARA, WESTERN AUSTRALIA","authors":"J. Kasbohm, B. Schoene, S. MacLennan, D. Evans, B. Weiss","doi":"10.1130/abs/2022am-380336","DOIUrl":"https://doi.org/10.1130/abs/2022am-380336","url":null,"abstract":"While rates of Phanerozoic plate movements and magnetic field reversals have been well studied, little is known about such phenomena on early Earth. The ca. 2.8 – 2.7 Ga Fortescue Group on the Pilbara craton in Western Australia has been recognized as a well-preserved sequence of Archean rift volcanics thought to derive from a flood basalt province, and may have been moving rapidly across the globe at two different intervals in its depositional history. We present the results of a magnetostratigraphic study integrated with high-precision U-Pb ID-TIMS geochronology aiming to quantify rates of cratonic motion and provide a continuous time series for changes in Pilbara paleogeography during these two rapid intervals, at ~2.77 and 2.72 Ga. We provide six new or updated high-quality paleomagnetic poles for inclusion in databases tracking Precambrian cratonic motion. During the craton ’ s largest geographic displacement at ~2.77 Ga, we resolve a minimum drift rate of 23 ± 20 cm/a if there was substantial rotation of the Pilbara craton along with translational motion, and a more rapid minimum estimate of 64 ± 23 cm/a if the motion was dominated by translation; these estimates exceed both Mesoarchean and most modern rates of plate motion. We provide a new high-precision U-Pb zircon age of 2721.23 ± 0.88/0.88/6.9 Ma for the Tumbiana Formation stromatolite colony, which developed as the Pilbara craton drifted from 51.5 ± 7.0 ◦ to 32.1 ± 5.7 ◦ paleolatitude. Although the Fortescue Group has been considered an early prototype of large igneous provinces, it was emplaced over a longer duration than its Phanerozoic counterparts and does not fit at least one definition of a large igneous province (LIP). But as a potential prototype of LIP magmatism, the Fortescue succession chronicles eruptive dynamics, rapid paleogeographic changes, and a series of robustly determined magnetic field reversals during the Neoarchean.","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83744203","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":"THERE AND BACK AGAIN: RECYCLING OF THE APPALACHIAN SIGNATURE IN DZ U-PB RECORDS OF PHANEROZOIC NORTH AMERICA","authors":"I. Allred, M. Blum, B. Frederick, Abdullah M. Wahbi","doi":"10.1130/abs/2022am-377461","DOIUrl":"https://doi.org/10.1130/abs/2022am-377461","url":null,"abstract":"\u0000 Continental-scale recycling of detrital zircon (DZ) grains and associated sediment across North American is not well understood. We trace a through line following the DZ proxy for the detritus originally sourced from Grenville and Appalachian orogens. This paper lays out an antecedent framework for one of the greatest sedimentation episodes of the Phanerozoic: the initial dispersal of Appalachian- and Grenville-age DZ grains to the western passive margin of Laurentia and the subsequent paleodrainage reorganization and sediment remobilization back to the east. The DZ U-Pb signature of the Appalachian-Ouachita orogenic system is dominated by Grenville (ca. 1250–950 Ma) and Appalachian (ca. 500–275 Ma) age groups and dominates the Phanerozoic record of North America. This study juxtaposes Pennsylvanian to modern DZ U-Pb data from across North America and demonstrates a persistent Appalachian signature, including a recycled Appalachian signature across Western North America. Lower Pennsylvanian deposits proximal to the Appalachian orogen are 50%–75% Appalachian- and Grenville-age DZ grains, representing the key component in the primary Appalachian signature. It remains unclear how the Appalachian signal was propagated to the west, but the Appalachian DZ signature was clearly present across the late Paleozoic passive margin of Laurentia and thus antecedent to potential DZ recycling throughout the Mesozoic and Cenozoic Eras. Triassic DZ samples document transcontinental fluvial systems that reached the western Laurentian margin, but subsequent Jurassic-Cretaceous samples indicate drainage reversal due to the rise of the Mesozoic Western Cordillera. A persistent Appalachian signature exists in these western-sourced, eastward-flowing systems—a phenomenon that continues to the present: samples are frequently composed of >40% Appalachian- and Grenville-age DZ. However, none of these systems are interpreted to be sourced by primary Appalachian or Grenville terranes, suggesting a recycled Appalachian signature. The persistent Appalachian signature, originally sourced by the linking of two orogenic terranes, continues to dominate the Phanerozoic record of much of North America to this day.","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88465240","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":"EXAMINING THE ONTOGENY OF THE PENNSYLVANIAN CLADID CRINOID ERISOCRINUS","authors":"Noel J. Hernandez Gomez, Lisette E. Melendez, Whitney A. Lapic, Sarah L. Sheffield, Ronald D. Lewis","doi":"10.1130/abs/2022nc-375495","DOIUrl":"https://doi.org/10.1130/abs/2022nc-375495","url":null,"abstract":"\u0000 Crinoids, the group known today as the sea lilies, were a major constituent of ocean environments from the late Carboniferous (323–299 million years ago). However, crinoid fossil-forming potential is poor, and they typically fell apart quickly after death. This limits our ability to study much about their life histories, including how they would have grown. Through the discovery of an area of exceptional fossil preservation in the Barnsdall Formation of Oklahoma, we have a rare chance to learn about the growth of one of these species of crinoids, Erisocrinus typus. Here we perform a growth analysis of a well-preserved series of fossils and discuss the patterns that it showed from its juvenile stage to adulthood.","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81926187","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":"“REEF SURVIVOR” – A NEW BOARD GAME DESIGNED TO TEACH COLLEGE AND UNIVERSITY UNDERGRADUATE STUDENTS ABOUT REEF ECOLOGY, EVOLUTION, AND EXTINCTION","authors":"R. Martindale, Barbara Sofia Sulbaran Reyes, Sinjini Sinha, North Cooc","doi":"10.1130/abs/2022am-380343","DOIUrl":"https://doi.org/10.1130/abs/2022am-380343","url":null,"abstract":"","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"116 9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84244251","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 INFLUENCE OF LARGE WOODY DEBRIS ON POST-WILDFIRE DEBRIS-FLOW SEDIMENT STORAGE","authors":"F. Rengers, L. McGuire, K. Barnhart, A. Youberg, D. Cadol, Alexander N. Gorr, Olivia J. Hoch, Rebecca Beers, J. Kean","doi":"10.1130/abs/2022am-378572","DOIUrl":"https://doi.org/10.1130/abs/2022am-378572","url":null,"abstract":"Abstract. Debris flows transport large quantities of water and granular material, such as sediment and wood, and this mixture can have devastating effects on life and infrastructure. The proportion of large woody debris (LWD) incorporated into debris flows can be enhanced in forested areas recently burned by wildfire because wood recruitment into channels accelerates in burned forests. In this study, using four small watersheds in the Gila National Forest, New Mexico, which burned in the 2020 Tadpole Fire, we explored new approaches to estimate debris flow velocity based on LWD characteristics and the role of LWD in debris flow volume retention. To understand debris flow volume model predictions, we examined two models for debris flow volume estimation: (1) the current volume prediction model used in US Geological Survey debris flow hazard assessments and (2) a regional model developed to predict the sediment yield associated with debris-laden flows. We found that the regional model better matched the magnitude of the observed sediment at the terminal fan, indicating the utility of regionally calibrated parameters for debris flow volume prediction. However, large wood created sediment storage upstream from the terminal fan, and this volume was of the same magnitude as the total debris flow volume stored at the terminal fans. Using field and lidar data we found that sediment retention by LWD is largely controlled by channel reach slope and a ratio of LWD length to channel width between 0.25 and 1. Finally, we demonstrated a method for estimating debris flow velocity based on estimates of the critical velocity required to break wood, which can be used in future field studies to estimate minimum debris flow velocity values.\u0000","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90500462","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":"MULTIPLE FORMS OF BIOIMMURATION IN A CORAL-CRINOID-BRYOZOAN ASSOCIATION FROM THE MIDDLE DEVONIAN ONONDAGA FORMATION OF SOUTHERN ONTARIO","authors":"J. Thomka, Lilian K. Gunderson","doi":"10.1130/abs/2022ne-375258","DOIUrl":"https://doi.org/10.1130/abs/2022ne-375258","url":null,"abstract":"A large favositid tabulate coral colony from the Middle Devonian Edgecliff Member of the Onondaga Formation, collected from Port Colborne, southernmost Ontario, is described herein because of several noteworthy paleontological features preserved via overgrowth by the coral. The initial substratum colonized and subsequently overgrown by the favositid was a large solitary rugose coral; and outward growth resulted in overgrowth of multiple macrofossils, including relatively long portions of large-diameter (probably camerate) crinoid columns. The crinoid columns, which likely represent portions of robust, recumbent dististelar attachment structures, are otherwise known almost entirely from isolated columnals at the collection locality and similar high-energy biostromal lithofacies in the Edgecliff Member elsewhere. One of the crinoid columns is encrusted by a stenolaemate bryozoan containing several examples of a parasitic bioclaustration structure similar to Catellocaula. Hence, the composite coral-crinoid-bryozoan association contains two forms of bioimmuration: preservation of the relatively intact crinoid columns via overgrowth and eventual incorporation into the base of the tabulate coral and preservation of the outline of the bioclaustrated organism (potentially an ascidian tunicate) via embedment in the bryozoan. This specimen serves as a testament to the diversity of biotic interactions and preservational mechanisms that occurred in Paleozoic carbonate buildups.","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"139 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85591607","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":"URANIUM AND MOLYBDENUM ISOTOPE EVIDENCE FOR GLOBALLY EXTENSIVE MARINE EUXINIA ON CONTINENTAL MARGINS AND IN EPICONTINENTAL SEAS DURING THE DEVONIAN-CARBONIFEROUS HANGENBERG CRISIS","authors":"B. Kendall, Shuai Yang, Xinze Lu, Xinming Chen, Wang Zheng, J. Owens, Seth A. Young","doi":"10.1130/abs/2022am-383366","DOIUrl":"https://doi.org/10.1130/abs/2022am-383366","url":null,"abstract":"","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80513017","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":"MONITORING THE IMPACTS OF THE 2022 HERMITS PEAK/CALF CANYON FIRE ON THE UPPER PECOS RIVER WATER QUALITY","authors":"Jennifer Lindline, Megan Begay, Letisha Mailboy","doi":"10.1130/abs/2022am-383797","DOIUrl":"https://doi.org/10.1130/abs/2022am-383797","url":null,"abstract":"The Upper Pecos Watershed (UPW), part of the Rio Grande Basin, extends from the headwaters of the Pecos River in the Sangre de Cristo Mountains (elevation > 12,000 ft) to its confluences with Cow Creek and El Rito (elevation ~ 6,000 ft). The Upper Pecos River supports recreation, agriculture, cattle grazing, tourism, and other uses. It is one of the most ecologically diverse and culturally significant waters of New Mexico. The UPW, along with nearby regional watersheds, was impacted by the 2022 Hermits Peak/Calf Canyon Fire, the largest wildfire in New Mexico’s history (>340,000 acres). Approximately 40,150 acres burned in the UPW, 34% of which were classified by the USFS Burned Area Emergency Response (BAER) team as high burn severity. Such classification raised concerns for post-fire impacts to water quality from increased river discharge, hillside erosion, and fire sedimentation. We collected weekly in-the-field physical-chemical parameters (conductivity, temperature, dissolved oxygen, and pH) using a YSI 556 Multi Probe and grab water samples for turbidity analysis using a Hach TL2300 turbidimeter throughout Summer 2022 to assess the after-effects of the wildfire. These data were compared to water quality data collected by our team in Summer 2020 and 2021 to determine if and how much the water quality departed from baseline values. From the onset of the monsoon rains (mid-June), ash and floating debris were observed in the stream, along with high turbidity and low dissolved oxygen values both in exceedance of the NMAC 20.6.4.900 water quality threshold (> 10.00 NTU and 6 mg/L respectively). Values of pH ranged between 3.79-7.69 with the lowest values corresponding roughly to high discharge events. Temperature and electrical conductivity met water quality standards for the Upper Pecos River’s high-quality cold-water designation (NMAC 20.6.2). We continue to monitor the river, as water quality in the system sets the basis for the rest of ecosystem health","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74898777","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":"HYDROCHEMISTRY OF AN ALPINE KARST SYSTEM, NORTHERN NEW MEXICO: LAS HUERTAS","authors":"Kambray Townsend, L. Crossey, K. Karlstrom, B. Griego, L. Crowley","doi":"10.1130/abs/2022am-378537","DOIUrl":"https://doi.org/10.1130/abs/2022am-378537","url":null,"abstract":"","PeriodicalId":12535,"journal":{"name":"Geological Society of America Abstracts with Programs","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80989538","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}