GPR STRATIGRAPHY AND QUATERNARY MORPHOGENESIS IN THE SEMIARID BRAZIL

Authors

DOI:

https://doi.org/10.4215/10.4215/rm2019.e18027

Abstract

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.     

Author Biographies

  • Marcelo Accioly Teixeira de Oliveira, Universidade Federal de Santa Catarina, Florianópolis (SC), Brasil

    Doutor em Geografia Física na Université de Paris IV (Paris-Sorbonne), realizando o trabalho de tese no Laboratório de Geografia Física do CNRS, em Meudon - Belle Vue (1992). Concluiu programas de Pós-doutorado em Geocronologia e Estratigrafia do Quaternário na Université de Paris XI (2000) e em Geofísica Aplicada no IAG-USP, São Paulo (2008). Atualmente é professor associado IV do Departamento de Geociências da Universidade Federal de Santa Catarina (UFSC). Tem experiência na área de Geociências, com ênfase em Estudos do Quaternário Continental, tendo atuado principalmente nos seguintes temas: processos erosivos e deposicionais, sedimentologia, micromorfologia, estratigrafia e palinologia do Quaternário, geofísica de reflexão por radar eletromagnético e avaliação de geomorfosítios. Tem experiência como perito judicial em processos de caráter ambiental. Após desenvolver linha de investigação focada na obtenção de dados representativos (proxies) continentais para interpretação paleoambiental, tem como foco principal de investigação a aplicação da estratigrafia de georadar (GPR) à estratigrafia do quaternário e à evolução do relevo continental.

  • Janaina Carla Santos, Universidade Federal do Vale do São Francisco, São Raimundo Nonato (PI), Brasil

    Doutora em Geociências pela Universidade Federal de Pernambuco (2007). Tem experiência na área de Geociências, com ênfase em Geologia e Geomorfologia do Quaternário, especialmente de áreas semiáridas. Atualmente é Professora Associada I do Colegiado de Arqueologia e Preservação Patrimonial e professora do Programa de Pós-Graduação de Arqueologia ambos da Universidade Federal do Vale do São Francisco.

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Published

2019-10-27

Issue

Vol. 18 (2019)

Section

Artigos

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