Holocene shifts of the Subtropical Shelf Front off southeastern South America controlled by high and low latitude atmospheric forcings

Autor(es)

Bender, Vera B. ^[1] ; Hanebuth, Till J. J. ^[1] ; Chiessi, Cristiano M. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Bremen, MARUM Ctr Marine Environm Sci, DE-28359 Bremen - Germany

^[2] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PALEOCEANOGRAPHY; v. 28, n. 3, p. 481-490, SEP 2013.
• Citações Web of Science: 12

Resumo

Over the Uruguayan shelf and uppermost slope, the coalescence of northward flowing Subantarctic Shelf Water and southward flowing Subtropical Shelf Water forms a distinct thermohaline front termed the Subtropical Shelf Front (STSF). Running in a SW direction diagonally across the shelf from the coastal waters at 32 degrees S toward the shelf break at ca. 36 degrees S, the STSF represents the shelfward extension of the Brazil-Malvinas Confluence zone. This study reconstructs latitudinal STSF shifts during the Holocene based on benthic foraminifera O-18 and C-13, total organic carbon, carbonate contents, Ti/Ca, and grain size distribution from a high-accumulation sedimentary record located at an uppermost continental-slope terrace. Our data provide direct evidence for: (1) a southern STSF position (to the South of the core site) at the beginning of the early Holocene (>9.4calka BP) linked to a more southerly position of the Southern Westerly Winds in combination with restricted shelf circulation intensity due to lower sea level; (2) a gradual STSF northward migration (bypassing the core site toward the North) primarily forced by the northward migration of the Southern Westerly Winds from 9.4calka BP onward; (3) a relatively stable position of the front in the interval between 7.2 and 4.0calka BP; (4) millennial-scale latitudinal oscillations close to 36 degrees S of the STSF after 4.0calka BP probably linked to the intensification in El Nino Southern Oscillation; and (5) a southward migration of the STSF during the last 200years possibly linked to anthropogenic influences on the atmosphere. (AU)

• Processo FAPESP: 11/50394-0 - Variabilidade do sistema de monção da América do Sul dos últimos três milênios integrando registros lacustres, espeleotemas e marinhos
• Beneficiário: Francisco William da Cruz Junior
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular
• Processo FAPESP: 12/17517-3 - Resposta da porção oeste do Oceano Atlântico às mudanças na circulação meridional do Atlântico: variabilidade milenar a sazonal
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores
• Processo FAPESP: 10/09983-9 - Mudanças na temperatura da superfície do mar no oeste do Atlântico Sul e variabilidade na precipitação no sudeste da América do Sul desde o Último Máximo Glacial
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Regular