Link between the North and South Atlantic during the Heinrich events of the last glacial period |
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| Authors: | L Vidal RR Schneider O Marchal T Bickert TF Stocker G Wefer |
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| Institution: | Universit?t Bremen, Geowissenschaften, FB5, D-28334 Bremen, Germany, E-mail: vidal@allgeo.uni-bremen.de, DE
Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland, CH
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| Abstract: | High resolution benthic oxygen isotope records combined with radiocarbon datings, from cores retrieved in the North, Equatorial,
and South Atlantic are used to establish a reliable cronostratigraphy for the last 60 ky. This common temporal framework enables
us to study the timing of the sub-Milankovitch climate variability in the entire surface Atlantic during this period, as reflected
in planktonic oxygen isotope records. Variations in sea surface temperatures in the Equatorial and South Atlantic reveal two
warm periods during the mid-stage 3 which are correlated to the warming observed in the North Atlantic after Heinrich events
(HL) 5 and 4. However, the records show that the warming started about 1500 y earlier in the South Atlantic. A zonally averaged
ocean circulation model simulates a similar north-south thermal antiphasing between the latitudes of our coring sites, when
pertubated by a freshwater flux anomaly. We infer that the observed phase relationship between the northern and the southern
Atlantic is related to periods of reduced NADW production in the North Atlantic, such as during HL5 and HL4.
Received: 24 November 1998 / Accepted: 16 May 1999 |
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