Phase relationship between sea level and abrupt climate change

15 pages, 10 figures, 2 tables.-- Printed version published

Direct traces of past sea levels are based on the elevation of old coral reefs at times of sea level highstands. However, these measurements are discontinuous and cannot be easily correlated with climate records from ice cores. In this study we show a new approach to recognizing the imprint of sea level changes in continuous sediment records taken from the continental slope at locations that were continuously submerged, even during periods of sea level lowstand. By using a sediment core precisely synchronized with Greenland ice cores, we were able to recognize major floods of the Mediterranean continental shelf over the past 270 kyr. During the last glacial period five flooding events were observed at the onset of the warmest Greenland interstadials. Consistent correspondence between warm climate episodes and eustatic sea level rises shows that these global flooding events were generated by pronounced melting of the Northern Hemisphere ice sheets, due to rapid intensification of Atlantic Meridional Overturning Circulation.

The method described in this study opens a new perspective for inter-hemispheric synchronization of marine climate records if applied in other continental margins from the Southern Hemisphere or the equatorial regions.

This work was supported by the European Comission Project PROMESS1 (contract EVR1-CT-2002-40024) and the IMAGES program that funded the drilling and coring of the Gulf of Lion. Support from Junta de Castilla y León (Grupo GR34), Ministerio de Educacion y Ciencia (including CGL 2005-00642/BTE, CGL2008-05560, REN 2003-08642-CO2/CLI, several RTD projects, complementary actions and the Consolider Ingenio “GRACCIE” program CSD 2007-00067) and Generalitat de Catalunya are also acknowledged, as well as the French Agence Nationale de la Recherche (ANR, contract NT05-3-42040).

Peer reviewed