Saline Indian Ocean waters invaded the South Atlantic thermocline during glacial termination II

Salty and warm Indian Ocean waters enter the South Atlantic via the Agulhas leakage, south of Africa. Model simulations and proxy evidence of Agulhas leakage strengthening during glacial terminations led to the hypothesis that it was an important modulator of the Atlantic Ocean circulation. Yet, the...

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 2015-02, Vol.43 (2), p.139-142
Main Authors: Scussolini, Paolo, Marino, Gianluca, Brummer, Geert-Jan A, Peeters, Frank J. C
Format: Article
Language:English
Subjects:
Agulhas Bank
Atlantic Ocean
Cenozoic
chemostratigraphy
cores
Foraminifera
Hydrography
Indian Ocean
Invertebrata
isotope ratios
isotopes
Leakage
Marine
marine sediments
microfossils
O-18/O-16
Ocean circulation
Oceanography
Oceans
oxygen
paleo-oceanography
paleotemperature
Pleistocene
Protista
Quaternary
Quaternary geology
Salinity
sediments
South Atlantic
stable isotopes
thermocline
upper Pleistocene
Walvis Ridge
water masses
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Salty and warm Indian Ocean waters enter the South Atlantic via the Agulhas leakage, south of Africa. Model simulations and proxy evidence of Agulhas leakage strengthening during glacial terminations led to the hypothesis that it was an important modulator of the Atlantic Ocean circulation. Yet, the fate of the leakage salinity and temperature anomalies remains undocumented beyond the southern tip of Africa. Downstream of the leakage, new paleoceanographic evidence from the central Walvis Ridge (southeast Atlantic) shows that salinity increased at the thermocline, and less so at the surface, during glacial termination II. Thermocline salinity change coincided with higher frequency of Agulhas rings passage at the core location and with salinity maxima in the Agulhas leakage area, suggesting that leakage waters were incorporated in the Atlantic circulation through the thermocline. Hydrographic changes at the Walvis Ridge and in the leakage area display a distinct two-step structure, with a reversal at ca. 134 ka. This matched a wet interlude within the East Asia weak monsoon interval of termination II, and a short-lived North Atlantic warming. Such concurrence points to a Bolling-Allerod-like recovery of the Atlantic circulation amidst termination II, with a northward shift of the Intertropical Convergence Zone and Southern Hemisphere westerlies, and attendant curtailment of the interocean connection south of Africa.
ISSN:0091-7613
1943-2682
DOI:10.1130/G36238.1