Neotectonic evolution of the Brazilian northeastern continental margin based on sedimentary facies and ichnology

Autor(es)

Gandini, Rosana ^[1] ; Rossetti, Dilce de Fatima ^[2] ; Netto, Renata Guimaraes ^[3] ; Rego Bezerra, Francisco Hilario ^[4] ; Goes, Ana Maria ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

^[2] Brazilian Natl Inst Space Res INPE, Div Remote Sensing, Sao Jose Dos Campos, SP - Brazil

^[3] Univ Rio dos Sinos UNISINOS, Grad Sch Geol, Sao Leopoldo, RS - Brazil

^[4] Fed Univ Rio Grande do Norte UFRN, Dept Geol, Natal, RN - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Quaternary Research; v. 82, n. 2, p. 462-472, SEP 2014.
• Citações Web of Science: 8

Resumo

Quaternary post-Barreiras sediments are widespread along Brazil's passive margin. These deposits are well exposed in the onshore Paraiba Basin, which is one of the rift basins formed during the Pangean continental break-up. In this area, the post-Barreiras sediments consist of sandstones with abundant soft-sediment deformation structures related to seismicity contemporaneous with deposition. The trace fossils Thalassinoides and Psilonichnus are found up to 38 m above modern sea level in sandstones dated between 60.0 (+/- 1.4) and 15.1 (+/- 1.8) ka. The integration of ichnological and sedimentary facies suggests nearshore paleoenvironments. Such deposits could not be related to eustatic sea-level rise, as this time coincides with the last glaciation. Hence, an uplift of 0.63 mm/yr, or 1.97 mm/yr if sea level was 80 m lower in the last glaciation, would have been required to ascend the post-Barreiras sediments several meters above the present-day sea level during the last 60 ka. This would suggest that the post-rift stage of the South American eastern passive margin may have experienced tectonic reactivation more intense than generally recognized. Although more complete data are still needed, the information presented herein may play an important role in studies aiming to decipher the Quaternary evolution of this passive margin. (C) 2014 University of Washington. Published by Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 12/06010-5 - Evolução tectono-sedimentar pós-rifte na bacia Paraíba, Nordeste do Brasil
• Beneficiário: Dilce de Fátima Rossetti
• Modalidade de apoio: Auxílio à Pesquisa - Regular