ESTRATIGRAFIA GPR E MORFOGÊNESE QUATERNÁRIA NO SEMIÁRIDO BRASILEIRO
Item
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Título
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ESTRATIGRAFIA GPR E MORFOGÊNESE QUATERNÁRIA NO SEMIÁRIDO BRASILEIRO
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Mercator
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Universidade Federal de Santa Catarina
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Universidade Federal do Vale do São Francisco
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Autor
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Marcelo Accioly Teixeira de Oliveira
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Janaina Carla Santos
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Assunto
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Estratigrafia
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GPR
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Morfogênese
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Quaternário
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Semiárido
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Serra da Capivara
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Abstract
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The Serra da Capivara National Park is a study case of choice for Quaternary and geomorphology studies in the semiarid northeastern Brazil. Previous research in the Serra Branca valley, which is one of the park’s main geomorphological units, reveals the predominance of thick colluvial deposits, suggesting episodic fluctuations towards wetter semiarid climates since the Upper Pleistocene. This study focuses on the application of GPR stratigraphy to Quaternary deposits along the three kilometers-wide middle reach of the Serra Branca valley. High-resolution GPR and RTK data and OSL dating suggest a more complex geomorphic evolution than previously envisioned. Results indicate the existence of gullied first-order watersheds that lie buried under small alluvial fan deposits since at least the Early to Middle Holocene. A 300 meters-wide alluvium filled paleo-channel is found, hanging about 14 meters higher than the present valley bottom and recording the incision of the valley since the Last Glacial Maximum. GPR and RTK data enable mapping truncated rock surfaces; colluvial and alluvial deposits; pediments; worn down watersheds; a relict fluvial channel, and the present valley bottom. Results suggest that the local climate was wetter than today during the last global glacial stage.
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volume
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18
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Date
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2019
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Língua
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en-US
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doi
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10.4215/10.4215/rm2019.e18027
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issn
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1984-2201
