Reconstrução da hidrografia superficial do Atlântico Sul Ocidental desde o Último Máximo Glacial a partir do estudo de foraminíferos planctônicos / Sea surface hydrography reconstruction of the Western South Atlantic since the Last Glacial Maximum based on the study of planktonic foraminifera

AUTOR(ES)

María Alejandra Gómez Pivel

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

10/03/2010

RESUMO

The goal of this thesis is to document the paleoclimatic and paleoceanographic changes occurred at the millennial scale since the Last Glacial Maximum at the surface Western South Atlantic. Paleotemperature, paleosalinity and paleoproductivity estimates were obtained for this purpose based on faunal changes of foraminifera assemblages, carbon and oxygen stable isotopes in Globigerinoides ruber and nine radiocarbon datings in a core retrieved at Santos Basin. These data were supplemented by the reanalysis of a second core previously analyzed from a different sector of the same basin. The results demonstrate that paleoceanographic changes recorded in the analyzed period may be partially explained by changes in the heat and salt export to the northern hemisphere related to the meridional overturning cell and the surface currents related to atmospheric circulation. Another significant portion of the observed variability seems to be related to changes in the strength of the South American Monsoon System resulting from insolation changes according to the precessional cycle. The main departures from the expected trend of variation in the isotopic composition of seawater related to insolation changes coincide with great meltwater pulses occurred around 19, 14, and 8.2 kyr BP.

ASSUNTO(S)

artificial neural networks bacia de santos deglaciação deglaciation foraminíferos planctônicos holocene holoceno last glacial maximum paleoceanografia paleoceanography planktonic foraminifera redes neurais artificiais santos basin sistema de monção da américa do sul. south american monsoon system Último máximo glacial

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