Radiocarbon geochronology of the sediments of the São Paulo Bight (southern Brazilian upper margin)

Anais da Academia Brasileira de Ciências

Michel M. Mahiques¹  Silvia H.m. Sousa¹  Leticia Burone¹  Renata H. Nagai¹  Ilson C.a. Silveira¹  Rubens C.l. Figueira¹  Rafael G. Soutelino¹  Leandro Ponsoni¹  Daniel A. Klein¹ 

[1] ,Universidade de São Paulo Instituto Oceanográfico São Paulo SP ,Brasil

关键词: continental margin;    quaternary;    radiocarbon;    sea-level;    sedimentation;    margem continental;    quaternário;    radiocarbono;    nível do mar;    sedimentação;   

DOI  :  10.1590/S0001-37652011005000028

来源: SciELO

【 摘 要 】

The aim of this work was to generate an inventory of the data on radiocarbon datings obtained from sediments of the São Paulo Bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon datings from materials collected using differents ampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr-1. The highest sedimentation rate values were found in a low-energy (ría type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the terrigenous input from the Río de La Plata outflow which is transported via the Brazilian Coastal Current, as well as of the coupled Brazil Current - Intermediate Western Boundary Current (BC-IWBC) dynamics on the sedimentary processes. At least three indicators ofthe paleo sea level were found at 12200 yr BP (conventional radiocarbon age) (103 meters below sea level - mbsl),8300-8800 cal yr BP (13 mbsl) and 7700-8100 cal yr BP (6 mbsl).

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