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vol.58 special issue 1Architecture and stratigraphic framework of shelf sedimentary systems off Rio de Janeiro state, Northern Santos Basin-BrazilCharacterization of the Brazilian continental shelf adjacent to Rio Grande do Norte state, NE Brazil author indexsubject indexarticles search
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Brazilian Journal of Oceanography

On-line version ISSN 1982-436X

Abstract

NAGAI, Renata Hanae et al. Paleoproductivity changes during the Late Quaternary in the southeastern Brazilian upper continental margin of the Southwestern Atlantic. Braz. j. oceanogr. [online]. 2010, vol.58, n.spe1, pp.31-41. ISSN 1982-436X.  https://doi.org/10.1590/S1679-87592010000500004.

Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.

Keywords : Foraminifera; Brazil Current; Late Quaternary; Southwestern Atlantic.

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