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description Publicationkeyboard_double_arrow_right Article 2008 GermanyPublisher:Elsevier BV A. Risse; Robert Trumbull; B. Coira; S. M. Kay; P. van den Bogaard;Late Cenozoic back-arc mafic volcanism in the southern Puna plateau of Argentina offers insights into the state of the mantle under the world’s second largest continental plateau. Previous studies of the mafic magmas in this region proposed a scenario of mantle melting due to lithospheric delamination and/or steepening of the subducting slab. However, few of the centers have been precisely dated, which limits any geodynamic interpretation. We present results of laser incremental-heating 40Ar/39Ar dating of 22 back-arc centers in the southern Puna, with emphasis on the Salar de Antofalla region where volcanic activity was most intense. Three localities yielded ages between 7.3 and 7.0 Ma which, along with 2 previous 7 Ma ages, firmly establishes that back-arc activity began as early as late Miocene. Volcanism continued through the Pleistocene but the peak was in the early Pliocene. This result has important tectonic implications. If, as previously suggested, magma genesis is related to lithospheric delamination, this process was underway by the latest Miocene in the southern Puna. Furthermore, since the mafic back-arc volcanism is considered to mark a change in fault kinematics from compressional to transtensional, the new age constraints indicate that this change took place in the early Pliocene. The spatial and age distributions of the mafic centers indicate that magmatism began, and remained focussed in, a region between Salar de Antofalla and Cerro Galan. This concentration is probably structurally controlled, as it corresponds to the intersection of the NW–SE striking Archibarca lineament zone and the sets of NNE–SSW faults that run parallel to the Salar de Antofalla basin.
OceanRep arrow_drop_down GFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesJournal of South American Earth SciencesArticle . 2008 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
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For further information contact us at helpdesk@openaire.euAccess Routesbronze 55 citations 55 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert OceanRep arrow_drop_down GFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesJournal of South American Earth SciencesArticle . 2008 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2008.03.002&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2022 Germany, BrazilPublisher:Elsevier BV Authors: Cristian Guacaneme; Sergio Caetano-Filho; Gustavo M. Paula-Santos; Marly Babinski; +5 AuthorsCristian Guacaneme; Sergio Caetano-Filho; Gustavo M. Paula-Santos; Marly Babinski; Paula L. Fraga-Ferreira; Carolina Bedoya-Rueda; Matheus Kuchenbecker; Humberto L.S. Reis; Ricardo I.F. Trindade;The sedimentary evolution of the Bambuí foreland basin system in the interior of West Gondwana is marked by periods of connection and isolation from the global ocean during the late Neoproterozoic and early Paleozoic. To understand the link between these periods and seawater redox conditions, we present an integrated study of trace-metal geochemistry and stratigraphy of the carbonate-siliciclastic rocks from the two lowermost second order transgressive-regressive sequences of the Bambuí Group, east Brazil. The basal 2nd-order sequence trace-metal pattern shows a progressive decrease of mass fractions of Co, Cr, Ni, Cu, Mo, U, V, Zn, and Cd, concomitant with a progressive decrease of Al and Fe contents and Mo/TOC ratios. Among all these elements, only Cd, Mo and U mass fractions seem to be less or not affected by detrital influence, so they can be used as reliable redox proxies for the paleoenvironmental analysis of the studied Bambuí strata. Moreover, normalization to aluminum shows a progressive increase of trace-metal enrichments for Cd and Mo in the order of 0.1–10 times and for U in the order of 1–100 times, accompanied by a progressive increase of organic carbon content upward section. These changes in sedimentary trace-metal patterns provide evidence for the chemical evolution of basinal deep-waters, whose conditions changed progressively from suboxic-anoxic to anoxic-euxinic at the basal transgressive-regressive sequence. We suggest that the paleomarine system represented by the basal Bambuí Group has probably evolved as an intracontinental silled basin recording changes in seawater chemistry associated with redox variations and restricted hydrographic conditions. Sedimentary trace-metal patterns indicate that Bambuí epeiric sea was initially in communication with open ocean followed by the marine restriction during the transgressive and regressive cycles, respectively. This resulted in a long deepwater residence time and chemical evolution of deep watermass as a response to tectonic pulses and consequent sea-level variations during the restricted stage. Under anoxic-euxinic conditions of seawater, trace metals scarcity and micronutrient fixation limitation would have impacted nitrate bioavailability, preventing the evolution of early benthic metazoans in the Bambuí paleomarine system during the late Ediacaran and early Cambrian.
Journal of South Ame... arrow_drop_down Journal of South American Earth Sciences; OceanRep; Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) - Universidade de São Paulo (USP)Article . 2022 . Peer-reviewedLicense: Elsevier TDMadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2022.103998&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu2 citations 2 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert Journal of South Ame... arrow_drop_down Journal of South American Earth Sciences; OceanRep; Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) - Universidade de São Paulo (USP)Article . 2022 . Peer-reviewedLicense: Elsevier TDMadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2022.103998&type=result"></script>'); --> </script>
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description Publicationkeyboard_double_arrow_right Article 2008 GermanyPublisher:Elsevier BV A. Risse; Robert Trumbull; B. Coira; S. M. Kay; P. van den Bogaard;Late Cenozoic back-arc mafic volcanism in the southern Puna plateau of Argentina offers insights into the state of the mantle under the world’s second largest continental plateau. Previous studies of the mafic magmas in this region proposed a scenario of mantle melting due to lithospheric delamination and/or steepening of the subducting slab. However, few of the centers have been precisely dated, which limits any geodynamic interpretation. We present results of laser incremental-heating 40Ar/39Ar dating of 22 back-arc centers in the southern Puna, with emphasis on the Salar de Antofalla region where volcanic activity was most intense. Three localities yielded ages between 7.3 and 7.0 Ma which, along with 2 previous 7 Ma ages, firmly establishes that back-arc activity began as early as late Miocene. Volcanism continued through the Pleistocene but the peak was in the early Pliocene. This result has important tectonic implications. If, as previously suggested, magma genesis is related to lithospheric delamination, this process was underway by the latest Miocene in the southern Puna. Furthermore, since the mafic back-arc volcanism is considered to mark a change in fault kinematics from compressional to transtensional, the new age constraints indicate that this change took place in the early Pliocene. The spatial and age distributions of the mafic centers indicate that magmatism began, and remained focussed in, a region between Salar de Antofalla and Cerro Galan. This concentration is probably structurally controlled, as it corresponds to the intersection of the NW–SE striking Archibarca lineament zone and the sets of NNE–SSW faults that run parallel to the Salar de Antofalla basin.
OceanRep arrow_drop_down GFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesJournal of South American Earth SciencesArticle . 2008 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2008.03.002&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 55 citations 55 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert OceanRep arrow_drop_down GFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesArticle . 2008Data sources: GFZ German Research Centre for GeosciencesJournal of South American Earth SciencesArticle . 2008 . Peer-reviewedLicense: Elsevier TDMData sources: Crossrefadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2008.03.002&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2022 Germany, BrazilPublisher:Elsevier BV Authors: Cristian Guacaneme; Sergio Caetano-Filho; Gustavo M. Paula-Santos; Marly Babinski; +5 AuthorsCristian Guacaneme; Sergio Caetano-Filho; Gustavo M. Paula-Santos; Marly Babinski; Paula L. Fraga-Ferreira; Carolina Bedoya-Rueda; Matheus Kuchenbecker; Humberto L.S. Reis; Ricardo I.F. Trindade;The sedimentary evolution of the Bambuí foreland basin system in the interior of West Gondwana is marked by periods of connection and isolation from the global ocean during the late Neoproterozoic and early Paleozoic. To understand the link between these periods and seawater redox conditions, we present an integrated study of trace-metal geochemistry and stratigraphy of the carbonate-siliciclastic rocks from the two lowermost second order transgressive-regressive sequences of the Bambuí Group, east Brazil. The basal 2nd-order sequence trace-metal pattern shows a progressive decrease of mass fractions of Co, Cr, Ni, Cu, Mo, U, V, Zn, and Cd, concomitant with a progressive decrease of Al and Fe contents and Mo/TOC ratios. Among all these elements, only Cd, Mo and U mass fractions seem to be less or not affected by detrital influence, so they can be used as reliable redox proxies for the paleoenvironmental analysis of the studied Bambuí strata. Moreover, normalization to aluminum shows a progressive increase of trace-metal enrichments for Cd and Mo in the order of 0.1–10 times and for U in the order of 1–100 times, accompanied by a progressive increase of organic carbon content upward section. These changes in sedimentary trace-metal patterns provide evidence for the chemical evolution of basinal deep-waters, whose conditions changed progressively from suboxic-anoxic to anoxic-euxinic at the basal transgressive-regressive sequence. We suggest that the paleomarine system represented by the basal Bambuí Group has probably evolved as an intracontinental silled basin recording changes in seawater chemistry associated with redox variations and restricted hydrographic conditions. Sedimentary trace-metal patterns indicate that Bambuí epeiric sea was initially in communication with open ocean followed by the marine restriction during the transgressive and regressive cycles, respectively. This resulted in a long deepwater residence time and chemical evolution of deep watermass as a response to tectonic pulses and consequent sea-level variations during the restricted stage. Under anoxic-euxinic conditions of seawater, trace metals scarcity and micronutrient fixation limitation would have impacted nitrate bioavailability, preventing the evolution of early benthic metazoans in the Bambuí paleomarine system during the late Ediacaran and early Cambrian.
Journal of South Ame... arrow_drop_down Journal of South American Earth Sciences; OceanRep; Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) - Universidade de São Paulo (USP)Article . 2022 . Peer-reviewedLicense: Elsevier TDMadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2022.103998&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu2 citations 2 popularity Top 10% influence Average impulse Average Powered by BIP!more_vert Journal of South Ame... arrow_drop_down Journal of South American Earth Sciences; OceanRep; Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) - Universidade de São Paulo (USP)Article . 2022 . Peer-reviewedLicense: Elsevier TDMadd ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.jsames.2022.103998&type=result"></script>'); --> </script>
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