Metal/Ca ratios in pockmarks and adjacent sediments on the SW Atlantic slope: Implications for redox potential and modern seepage

Autor(es)

dos Santos, Rosangela Felicio ^[1] ; Nagaoka, Doris ^[1] ; Ramos, Raissa Basti ^[1] ; Salaroli, Alexandre Barbosa ^[1] ; Taniguchi, Satie ^[1] ; Lopes Figueira, Rubens Cesar ^[1] ; Bicego, Marcia Caruso ^[1] ; Lobo, Francisco Jose ^[2] ; Schattner, Uri ^[3] ; de Mahiques, Michel Michaelovitch ^{[1, 4]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Oceanog Inst, Praca Oceanog 191, BR-05508120 Sao Paulo - Brazil

^[2] Univ Granada, Inst Andaluz Ciencias Tierra, CSIC, Ave las Palmeras 4, Armilla - Spain

^[3] Univ Haifa, Dr Moses Strauss Dept Marine Geosci, Leon H Charney Sch Marine Sci, Haifa - Israel

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

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF GEOCHEMICAL EXPLORATION; v. 192, p. 163-173, SEP 2018.
• Citações Web of Science: 1

Resumo

Metal/Ca ratios and their corresponding enrichment factors (EFs) in bulk sediment samples collected at a mixed carbonate-siliciclastic continental slope setting with an extensive pockmark field were measured and analyzed to find evidence of lateral differences in the redox potential and recent seepage activity inside the pockmarks. The analyzed ratios point to metal enrichments that indicate variations in the redox potential inside the pockmarks compared to the adjacent areas, as shown by the Cu/Ca, Ni/Ca and Zn/Ca EFs. Slight but statistically significant differences in the Mg/Ca ratios indicated that the formation of Mg-enriched carbonates within the pockmarks is presently taking place, attesting the maintenance of seepage in the shallow sedimentary column. Recent seepage activity was also confirmed by the upward enrichment of Ba in the sedimentary column. Our study provides direct evidence for pockmark activity and reinforces the need for an extended analysis of the geochemistry of natural seepages on the SW Atlantic margin, an area that has still not been studied in relation to this subject. (AU)

• 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: 16/24379-7 - Utilização de marcadores geoquímicos em uma área de pockmarks (talude continental do Sul do Brasil)
• Beneficiário: Rosângela Felício dos Santos
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• 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
• 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