Geomorphological imprint of opposing ocean bottom currents, a case study from the southeastern Brazilian Atlantic margin

Autor(es)

de Mahiques, M. M. ^{[1, 2]} ; Lobo, F. J. ^[3] ; Schattner, U. ^[4] ; Lopez-Quiros, A. ^[3] ; Rocha, C. B. ^{[5, 6]} ; Dias, R. J. S. ^[1] ; Montoya-Montes, I ^{[7, 8]} ; Vieira, A. C. B. ^[1]

Afiliação do(s) autor(es)

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

^[2] Univ Sao Paulo, Inst Energy & Environm, Sao Paulo - Brazil

^[3] CSIC Univ Granada, Inst Andaluz Ciencias Tierra, Granada - Spain

^[4] Univ Haifa, Leon H Charney Sch Marine Sci, Dr Moses Strauss Dept Marine Geosci, Haifa - Israel

^[5] Univ Connecticut, Storrs, CT - USA

^[6] Woods Hole Oceanog Inst, Falmouth, MA - USA

^[7] Univ Las Palmas Gran Canaria, Inst Oceanog & Cambio Global IOCAG, Las Palmas Gran Canaria - Spain

^[8] Inst Geol & Minero Espana, Unidad Canarias, Las Palmas Gran Canaria - Spain

• Tipo de documento: Artigo Científico
• Fonte: MARINE GEOLOGY; v. 444, FEB 2022.
• Citações Web of Science: 0

Resumo

The combination of oceanographic processes and a negligible fluvial terrestrial sediment contribution makes the Santos Basin margin (southwestern Brazil) a unique environment for studying thew morphological imprint of bottom currents on the seafloor morphology. We divide the seafloor into four domains: outer shelf, upper, middle, and lower slope, based on an analysis of sub-bottom Chirp profiles, multichannel seismic data, hydro graphic data, numerical simulation outputs, and a seismic-derived bathymetry map. A clinoform at the outer shelf and upper slope, topped by erosional morphologies, developed below the SW-flowing Brazil Current (BC). At the bottom of the upper slope, a rugged and mounded surface around 600 mbsl coincides with the current flow reversal to the underlying NE-flowing Intermediate Western Boundary Current (IWBC). The smooth middle slope exhibits sheeted contourites interrupted by occasional channel-and-mound complexes. From the middle slope base, salt tectonics becomes a major player in setting the seafloor morphology. The slope-parallel Santos Channel develops above a subsurface diapir and the Cabo Frio Fault. The latter divides between the landward gap in subsurface Albian salt and the basinward rich diapir realm. Hence, the lower slope is reworked by the SW-flowing Deep Western Boundary Current (DWBC); however, salt tectonics dictates its morphology. Our study consists of a unique example for studying the morpho-sedimentary imprint of a countercurrent flowing on the continental slope and also for exploring the interaction between bottom flows with a suite of endogenic processes, such as salt tectonics, fluid flows, and mass movements. (AU)

• Processo FAPESP: 14/08266-2 - Feições morfológicas do talude continental da margem Sudeste do Brasil: tectônica ativa versus condições oceanográficas modernas
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/06147-5 - Incremento da capacidade de pesquisa em oceanografia no estado de São Paulo
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular
• Processo FAPESP: 19/06250-5 - Exposição de diápiros no fundo oceânico como um indicador de correntes: um estudo de caso na Bacia de Santos, Brasil
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/17763-2 - Mudbelts do Sul e Sudeste do Brasil: implicações sobre as influências antrópicas no ambiente marinho
• Beneficiário: Márcia Caruso Bícego
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 20/03363-0 - Ecofacies do sistema acoplado Corrente do Brasil - Corrente de Contorno Intermediária
• Beneficiário: Ana Carolina Barbosa Vieira
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica