{"title":"Submarine volcanism along shallow ridges did not drive Cryogenian cap carbonate formation: REPLY","authors":"Adriana Dutkiewicz, R. Dietmar Müller","doi":"10.1130/g52425y.1","DOIUrl":"https://doi.org/10.1130/g52425y.1","url":null,"abstract":"Abstract not available","PeriodicalId":12642,"journal":{"name":"Geology","volume":"74 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K.B. Kimi, Harish Harish, K.S. Sharini, Anil Chavan, S. Vijayan
The lava tube in the Gruithuisen region on the Moon is intriguing because it is characterized by a distinctive chain of collapsed pits and raised features, providing an opportunity to understand the potential morphologic deformation of lunar lava tubes under compressional stress. This study aimed to understand the morphological deformation in the Gruithuisen region’s lava tube when subjected to compressional stress. A combination of numerical simulations and morphometric analysis was employed to achieve this objective. The morphometric analysis of different collapsed and raised features associated with a lava tube in the study area revealed eight characteristic morphologies ranging from curvilinear channel-like to elliptical shape. Notably, average normal stress and strain values derived from a wrinkle ridge were found to be ~70 MPa and 2 × 10−3, respectively, and wrinkle ridges exhibited a northward orientation. These quantified parameters were utilized as the foundation for initializing three-dimensional models. Furthermore, the outcomes of the models closely replicated the deformation in the Gruithuisen region, emphasizing the significant role of compressional stress in the deformation of the lava tube. These models suggest that the observed eight unique features associated with the lava tube arise from disparities in displacement magnitude and direction along three axes (x, y, z). Our research sheds light on the structural transformations of lava tubes when subjected to varying compressional stress and enhances understanding of the ways in which the interplay between compressional tectonic activity and lava tube features has shaped the Moon’s surface.
{"title":"Deformation of the Gruithuisen region lava tube under compressional stress on the Moon","authors":"K.B. Kimi, Harish Harish, K.S. Sharini, Anil Chavan, S. Vijayan","doi":"10.1130/g52143.1","DOIUrl":"https://doi.org/10.1130/g52143.1","url":null,"abstract":"The lava tube in the Gruithuisen region on the Moon is intriguing because it is characterized by a distinctive chain of collapsed pits and raised features, providing an opportunity to understand the potential morphologic deformation of lunar lava tubes under compressional stress. This study aimed to understand the morphological deformation in the Gruithuisen region’s lava tube when subjected to compressional stress. A combination of numerical simulations and morphometric analysis was employed to achieve this objective. The morphometric analysis of different collapsed and raised features associated with a lava tube in the study area revealed eight characteristic morphologies ranging from curvilinear channel-like to elliptical shape. Notably, average normal stress and strain values derived from a wrinkle ridge were found to be ~70 MPa and 2 × 10−3, respectively, and wrinkle ridges exhibited a northward orientation. These quantified parameters were utilized as the foundation for initializing three-dimensional models. Furthermore, the outcomes of the models closely replicated the deformation in the Gruithuisen region, emphasizing the significant role of compressional stress in the deformation of the lava tube. These models suggest that the observed eight unique features associated with the lava tube arise from disparities in displacement magnitude and direction along three axes (x, y, z). Our research sheds light on the structural transformations of lava tubes when subjected to varying compressional stress and enhances understanding of the ways in which the interplay between compressional tectonic activity and lava tube features has shaped the Moon’s surface.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"72 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thomas M. Gernon, Thea K. Hincks, Toby Tyrrell, Eelco J. Rohling, Martin R. Palmer
Abstract not available
无摘要
{"title":"Submarine volcanism along shallow ridges did not drive Cryogenian cap carbonate formation: COMMENT","authors":"Thomas M. Gernon, Thea K. Hincks, Toby Tyrrell, Eelco J. Rohling, Martin R. Palmer","doi":"10.1130/g52317c.1","DOIUrl":"https://doi.org/10.1130/g52317c.1","url":null,"abstract":"Abstract not available","PeriodicalId":12642,"journal":{"name":"Geology","volume":"25 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gustavo G. Voldman, Gabriela A. Cisterna, Andrea F. Sterren, Miguel Ezpeleta, James E. Barrick
We present the first discovery of Late Paleozoic conodonts in Argentina, marking the southernmost occurrence of this fossil group in the dominantly cold, high latitudes of Gondwana. Recovered from the siliciclastic Río del Peñón (RDP) Formation at the Rincón Blanco section in the northern Precordillera, La Rioja Province, the fossil assemblage includes Neognathodus colombiensis and Neognathodus “pre-colombiensis,” precisely indicating the early Moscovian (late Atokan in North America) N. colombiensis Zone. Furthermore, the conodont fauna establishes a crucial temporal constraint for the brachiopod Tivertonia jachalensis–Streptorhynchus inaequiornatus (TS) Zone, which is a widely employed biostratigraphic unit in southern South America. The warm-water affinity of Neognathodus is in accordance with the record of typical paleoequatorial faunal elements in the TS Zone in several central western Argentinian basins, thus reinforcing the idea of a climatic amelioration in the southern latitudes of Gondwana during the early Moscovian.
{"title":"First documentation of Late Paleozoic conodonts from Argentina: Biostratigraphic and paleoclimatic constraints for the Late Paleozoic Ice Age in SW Gondwana","authors":"Gustavo G. Voldman, Gabriela A. Cisterna, Andrea F. Sterren, Miguel Ezpeleta, James E. Barrick","doi":"10.1130/g52133.1","DOIUrl":"https://doi.org/10.1130/g52133.1","url":null,"abstract":"We present the first discovery of Late Paleozoic conodonts in Argentina, marking the southernmost occurrence of this fossil group in the dominantly cold, high latitudes of Gondwana. Recovered from the siliciclastic Río del Peñón (RDP) Formation at the Rincón Blanco section in the northern Precordillera, La Rioja Province, the fossil assemblage includes Neognathodus colombiensis and Neognathodus “pre-colombiensis,” precisely indicating the early Moscovian (late Atokan in North America) N. colombiensis Zone. Furthermore, the conodont fauna establishes a crucial temporal constraint for the brachiopod Tivertonia jachalensis–Streptorhynchus inaequiornatus (TS) Zone, which is a widely employed biostratigraphic unit in southern South America. The warm-water affinity of Neognathodus is in accordance with the record of typical paleoequatorial faunal elements in the TS Zone in several central western Argentinian basins, thus reinforcing the idea of a climatic amelioration in the southern latitudes of Gondwana during the early Moscovian.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"48 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M.C. Zarazúa-Carbajal, G.A. Valentine, S. De la Cruz-Reyna
Alluvial processes acting on scoria cones cause the development of a drainage network composed of radially distributed rills and gullies parallel to the volcanic edifice's downslope direction. We quantify the degree of drainage network development by applying the Average Erosion Index (AEI) method to scoria cones from the arid to semi-arid Lunar Crater volcanic field (Nevada, United States) and comparing our results with previously obtained results from two tropical volcanic fields (Sierra Chichinautzin volcanic field and the Parícutin-Tancítaro region, both in central Mexico). We show that the AEI method is useful in determining geomorphic age relations when calibrated separately for each field. Furthermore, the differences in AEI results for the three studied fields indicate that the method provides a way of quantifying the effects of different alluvial erosion rates at volcanic fields across various environments, including a delay in alluvial processes on cones in arid settings that has been qualitatively inferred by previous studies.
{"title":"Scoria cone erosional degradation by incision: Different behaviors in three volcanic fields reflect environmental conditions","authors":"M.C. Zarazúa-Carbajal, G.A. Valentine, S. De la Cruz-Reyna","doi":"10.1130/g52113.1","DOIUrl":"https://doi.org/10.1130/g52113.1","url":null,"abstract":"Alluvial processes acting on scoria cones cause the development of a drainage network composed of radially distributed rills and gullies parallel to the volcanic edifice's downslope direction. We quantify the degree of drainage network development by applying the Average Erosion Index (AEI) method to scoria cones from the arid to semi-arid Lunar Crater volcanic field (Nevada, United States) and comparing our results with previously obtained results from two tropical volcanic fields (Sierra Chichinautzin volcanic field and the Parícutin-Tancítaro region, both in central Mexico). We show that the AEI method is useful in determining geomorphic age relations when calibrated separately for each field. Furthermore, the differences in AEI results for the three studied fields indicate that the method provides a way of quantifying the effects of different alluvial erosion rates at volcanic fields across various environments, including a delay in alluvial processes on cones in arid settings that has been qualitatively inferred by previous studies.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"74 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141475318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dunfan Wang, Yihui Chen, Yan Liu, Andrew P. Roberts, Eelco J. Rohling, Xiangyu Zhao, Xu Zhang, Jinhua Li, Weiqi Yao, Xuejiao Qu, Xianfeng Tan, Qingsong Liu
Global cooling with the onset of Antarctic glaciation ca. 34 Ma across the Eocene-Oligocene transition (EOT) terminated the early Cenozoic greenhouse climate state and marked the beginning of icehouse conditions. Although a pCO2 decline is considered to have been a major cause of this climate shift, the associated carbon-sequestration mechanism remains unclear. Here, we assessed ocean production and circulation changes across the EOT using numerical simulations combined with a novel proxy, namely, bacterial magnetofossils, the abundance and morphology of which are sensitive to sedimentary organic matter accumulation and oxygenation. We detected production and oxygenation declines in the equatorial Pacific Ocean coeval with increased biological production in the Southern Ocean after the EOT. Corroborated by simulation results and evidence from the Subantarctic region, we interpret this counterintuitive combination as a result of enhanced bottom-water formation and biological pump efficiency in the Southern Ocean due to Antarctic glacial buildup across the EOT. These results provide key evidence for deep Pacific Ocean deoxygenation and increased respired carbon concentrations, which amplified CO2 decline across the EOT.
{"title":"Bacterial magnetofossil evidence for enhanced Pacific Ocean respired carbon storage during buildup of Antarctic glaciation","authors":"Dunfan Wang, Yihui Chen, Yan Liu, Andrew P. Roberts, Eelco J. Rohling, Xiangyu Zhao, Xu Zhang, Jinhua Li, Weiqi Yao, Xuejiao Qu, Xianfeng Tan, Qingsong Liu","doi":"10.1130/g52016.1","DOIUrl":"https://doi.org/10.1130/g52016.1","url":null,"abstract":"Global cooling with the onset of Antarctic glaciation ca. 34 Ma across the Eocene-Oligocene transition (EOT) terminated the early Cenozoic greenhouse climate state and marked the beginning of icehouse conditions. Although a pCO2 decline is considered to have been a major cause of this climate shift, the associated carbon-sequestration mechanism remains unclear. Here, we assessed ocean production and circulation changes across the EOT using numerical simulations combined with a novel proxy, namely, bacterial magnetofossils, the abundance and morphology of which are sensitive to sedimentary organic matter accumulation and oxygenation. We detected production and oxygenation declines in the equatorial Pacific Ocean coeval with increased biological production in the Southern Ocean after the EOT. Corroborated by simulation results and evidence from the Subantarctic region, we interpret this counterintuitive combination as a result of enhanced bottom-water formation and biological pump efficiency in the Southern Ocean due to Antarctic glacial buildup across the EOT. These results provide key evidence for deep Pacific Ocean deoxygenation and increased respired carbon concentrations, which amplified CO2 decline across the EOT.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"72 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141463916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jonah S. McLeod, Alexander C. Whittaker, Rebecca E. Bell, Gary J. Hampson, Stephen E. Watkins, Sam A.S. Brooke, Nahin Rezwan, Joel Hook, Jesse R. Zondervan, Vamsi Ganti, Sinéad J. Lyster
Sediment transport in rivers is not steady through time. Highly intermittent river systems, which only transport bedload during the most significant flow events, are particularly sensitive to changes in climate and precipitation patterns. People and landscapes can be vulnerable to fluvial processes, and quantifying river intermittency is critical for assessing landscape response to projected changes in precipitation extremes due to climate change. We generated new constraints on recent to modern fluvial intermittency factors—the frequency at which bedload is mobilized in a river—based on field measurements in the Corinth Rift, Greece, and Holocene sediment accumulation rates. Results reveal some of the lowest documented intermittency factors to date, showing Mediterranean rivers can transport an entire annual sediment load in a rare storm event. Coupling intermittency calculations with historical flood and precipitation data indicates these rivers transport bedload during one storm every ~4 yr, associated with rainfall >50 mm/d, and subsequent floods; this hydroclimate is typical across the Mediterranean region. Furthermore, climate models predict precipitation extremes will increase across Europe, and the frequency of events that surpass thresholds of sediment transport will increase significantly, potentially causing sediment loads to double by 2100 CE. As the area of arid land likely to host intermittent rivers also increases, sensitive landscapes are on the edge of significant geomorphic change, driven by global warming.
{"title":"Landscapes on the edge: River intermittency in a warming world","authors":"Jonah S. McLeod, Alexander C. Whittaker, Rebecca E. Bell, Gary J. Hampson, Stephen E. Watkins, Sam A.S. Brooke, Nahin Rezwan, Joel Hook, Jesse R. Zondervan, Vamsi Ganti, Sinéad J. Lyster","doi":"10.1130/g52043.1","DOIUrl":"https://doi.org/10.1130/g52043.1","url":null,"abstract":"Sediment transport in rivers is not steady through time. Highly intermittent river systems, which only transport bedload during the most significant flow events, are particularly sensitive to changes in climate and precipitation patterns. People and landscapes can be vulnerable to fluvial processes, and quantifying river intermittency is critical for assessing landscape response to projected changes in precipitation extremes due to climate change. We generated new constraints on recent to modern fluvial intermittency factors—the frequency at which bedload is mobilized in a river—based on field measurements in the Corinth Rift, Greece, and Holocene sediment accumulation rates. Results reveal some of the lowest documented intermittency factors to date, showing Mediterranean rivers can transport an entire annual sediment load in a rare storm event. Coupling intermittency calculations with historical flood and precipitation data indicates these rivers transport bedload during one storm every ~4 yr, associated with rainfall >50 mm/d, and subsequent floods; this hydroclimate is typical across the Mediterranean region. Furthermore, climate models predict precipitation extremes will increase across Europe, and the frequency of events that surpass thresholds of sediment transport will increase significantly, potentially causing sediment loads to double by 2100 CE. As the area of arid land likely to host intermittent rivers also increases, sensitive landscapes are on the edge of significant geomorphic change, driven by global warming.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"92 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141475316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fluvial response to Late Pleistocene–Holocene climate change in the Colorado River drainage, central Texas, USA: COMMENT","authors":"Mike Blum, Dustin Sweet","doi":"10.1130/g51850c.1","DOIUrl":"https://doi.org/10.1130/g51850c.1","url":null,"abstract":"Abstract not available","PeriodicalId":12642,"journal":{"name":"Geology","volume":"55 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140814414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fluvial response to Late Pleistocene–Holocene climate change in the Colorado River drainage, central Texas, USA: REPLY","authors":"E. Gabriela Gutiérrez, Daniel F. Stockli","doi":"10.1130/g52087y.1","DOIUrl":"https://doi.org/10.1130/g52087y.1","url":null,"abstract":"Abstract not available","PeriodicalId":12642,"journal":{"name":"Geology","volume":"78 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140814428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Juan Pedro Rodríguez-López, Carlos L. Liesa, Aránzazu Luzón, Arsenio Muñoz, María J. Mayayo, Julian B. Murton, Ana R. Soria
Abstract not available
无摘要
{"title":"Ice-rafted dropstones at midlatitudes in the Cretaceous of continental, Iberia: REPLY","authors":"Juan Pedro Rodríguez-López, Carlos L. Liesa, Aránzazu Luzón, Arsenio Muñoz, María J. Mayayo, Julian B. Murton, Ana R. Soria","doi":"10.1130/g52152y.1","DOIUrl":"https://doi.org/10.1130/g52152y.1","url":null,"abstract":"Abstract not available","PeriodicalId":12642,"journal":{"name":"Geology","volume":"160 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140346097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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