The deglacial history of the western tropical Atlantic as inferred from high resolution stable isotope records off northeastern Brazil

被引：91

作者：

Arz, HW ^{[1
]}

Pätzold, J ^{[1
]}

Wefer, G ^{[1
]}

机构：

[1] Univ Bremen, Fachbereich Geowissenschaft 5, D-28334 Bremen, Germany

来源：

EARTH AND PLANETARY SCIENCE LETTERS | 1999年 / 167卷 / 1-2期

关键词：

paleoclimatology; thermohaline circulation; O-18; foraminifera; South Atlantic;

D O I：

10.1016/S0012-821X(99)00025-4

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

The western South Atlantic boundary currents represent a sensitive system within the global thermohaline circulation (THC). We investigated the impact of deglacial THC changes on the western tropical Atlantic studied in six high resolution sediment cores from the upper continental slope of Brazil. The stratigraphy of the cores is mainly based on C-14 AMS dating of monospecific foraminiferal samples. Changes in the upper layer tropical ocean during the deglaciation are inferred from stable oxygen isotope measurements on planktic and benthic foraminifera. Variations in the delta(18)O residuals are assumed to be mainly temperature related. During the Oldest and Younger Dryas cooling periods, two major deglacial THC disturbances are reported from North Atlantic sediment cores. Concomitant to the repeated THC slowdown, we observe an upper layer warming in the tropical ocean. A reduced northward heat export from the tropical areas during these periods (weak North Brazil Current) is additionally reflected by low meridional gradients in the stable oxygen records. This generally agrees with results from coupled ocean atmosphere models. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

引用

页码：105 / 117

页数：13

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