Mudanças Ambientais Ocorridas entre Abrolhos (BA) e Cabo Frio (RJ) ao Longo do Holoceno, e sua Resposta nas Associações de Foraminíferos

RAQUEL FERNANDA PASSOS, SILVIA HELENA MELLO E SOUsA, MICHEL MICHAELOVITCH MAHIQUES

Resumo


The assemblages of foraminifera present in eight box cores collected on the continental slope between Abrolhos Bank (BA) and Cabo Frio (RJ), were studied to determine the Holocene paleoceanographical history of the region. This study employed classical techniques for the analysis of paleoceanography, such as stable oxygen isotopes, micropaleontology and AMS 14C datings. Information on sea surface paleotemperature was obtained by measuring the abundance of various taxa of foraminifera: Globigerinoides ruber and Globigerinoides sacculifer as  indicators of warm water masses; Globigerina bulloides and Globigerinita sp. of cold water masses; Globorotalia menardii of warm climate and Globorotalia truncatulinoides of cool climate. The data obtained are in accordance with the results of isotopic analysis and other studies which have been carried out in this region. This study revealed a strong relationship between temperature and primary productivity in the Cabo Frio region, variation in the terrigenous input furnished by the Rio Doce, and occurrence of a regional upwelling southward of the Abrolhos Bank that was associated with sea level changes reflecting events associated with the Last Glacial Maximum (ca. 18 Ka BP).


Palavras-chave


foraminifera; Holocene; paleoceanographical.

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DOI: https://doi.org/10.22456/1807-9806.20297

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