Relative timing of precipitation and ocean circulation changes in the western equatorial Atlantic over the last 45 kyr

• DOI: 10.5194/cp-14-1315-2018
• Publication Date: 2018-09-18T07:30:47Z
• Authors: Claire Waelbroeck; Sylvain Pichat; Evelyn Böhm; Bryan C. Lougheed; Davide Faranda; Mathieu Vrac; Lise Missiaen; Natalia Vazquez R...; Pierre Burckel; Jörg Lippold; Helge W. Arz; Trond Dokken; François Thil; Arnaud Dapoigny
• Keywords: Stadial; Gulf Stream

Abstract. Thanks to its optimal location on the northern Brazilian margin, core MD09-3257 records both ocean circulation and atmospheric changes. The latter occur locally in form of increased rainfall adjacent continent during cold intervals recorded Greenland ice North Atlantic sediment cores (i.e., stadials). These events are as peaks ln(Ti ∕ Ca). New sedimentary Pa Th data indicate that mid-depth western equatorial water mass transport decreased all stadials last 40 kyr. Using cross-wavelet transforms spectrogram analysis, we assess relative phase between Ca) signals. We show a depth ∼1300 2300 m preceded over by 120 400 yr at Dansgaard–Oeschger (D–O) frequencies, 280 980 Heinrich-like frequencies. suggest large lead changes with respect tropical South American precipitation frequencies is related effect positive feedback involving iceberg discharges Atlantic. In contrast, absence widespread rafted detrital layers D–O supports hypothesis such this was not triggered case stadials, slowdowns subsequent remaining more limited than Heinrich stadials.