The Alpha Crucis Carbonate Ridge (ACCR): Discovery of a giant ring-shaped carbonate complex on the SW Atlantic margin

Autor(es)

Maly, Mascimiliano ^[1] ; Schattner, Uri ^[2] ; Jose Lobo, Francisco ^[3] ; Soares Dias, Rodolfo Jasao ^[1] ; Ramos, Raissa Basti ^[1] ; Couto, Daniel de Matos ^[1] ; Gomes Sumida, Paulo Yukio ^[1] ; de Mahiques, Michel Michaelovitch ^{[1, 4]}

Afiliação do(s) autor(es)

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

^[2] Univ Haifa, Leon H Charney Sch Marine Sci, Dr Moses Strauss Dept Marine Geosci, Haifa - Israel

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

^[4] Univ Sao Paulo, Inst Energy & Environm, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SCIENTIFIC REPORTS; v. 9, DEC 10 2019.
• Citações Web of Science: 0

Resumo

Recently acquired bathymetric and high-resolution seismic data from the upper slope of Santos Basin, southern Brazilian margin, reveal a major geomorphological feature in the SW Atlantic that is interpreted as a carbonate ridge - the Alpha Crucis Carbonate Ridge (ACCR). The ACCR is the first megastructure of this type described on the SW Atlantic margin. The -17 x 11-km-wide ring-shaped ACCR features tens of >100-m-high steep-sided carbonate mounds protruding from the surrounding seabed and flanked by elongated depressions. Comet-like marks downstream of the mound structures indicate that the area is presently influenced by the northward flow of the Intermediate Western Boundary Current (IWBC), a branch of the Subtropical Gyre that transports Antarctic Intermediate Water. Abundant carbonate sands and gravels cover the mounds and are overlain by a biologically significant community of living and dead ramified corals and associated invertebrates. The IWBC acts as a hydrodynamic factor that is responsible for both shaping the bottom and transporting coral larvae. We contend that the ACCR was formed by upward fluid flow along active sub-surface faults and fractures that formed by lateral extension generated by the ascending movement of salt diapirs at depth. The ACCR provides an important modern and accessible analogue for a seabed carbonate build-up related to sub-surface hydrocarbon systems. (AU)

• 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: 16/22194-0 - Feições anômalas de fundo no talude superior do Sul do Brasil
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/50191-8 - Dymamics of salt dome exhumation on the ocean floor, focusing on Santos basin offshore Brazil
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• 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