30/7/10

Phase relationship between sea level and abrupt climate change

SCIENCE DIRECT


Francisco J. Sierroa,   Nils Andersenb, Maria A. Bassettic, Serge Bernéc, f, Miquel Canalsd, Jason H. Curtise, Bernard Dennielouf, Jose Abel Floresa, Jaime Frigolad, Beatriz Gonzalez-Moraa, Joan O. Grimaltg, David A. Hodelle, Gwenael Jouetf, Marta Pérez-Folgadoa and Ralph Schneiderh

aDepartment of Geology, University of Salamanca, 37071 Salamanca, Spain
bLeibniz Laboratory for Radiometric Dating and Isotope Research, Christian-Albrechts Universität zu Kiel, Max-Eyth-Str. 11, 24118 Kiel, Germany
cLaboratoire IMAGES (BatU), Université de Perpignan, 52 Avenue Paul Alduy, 66860 Perpignan Cedex 9, France
dG.R.C. Marine Geosciences, Department of Stratigraphy, Paleontology and Marine Geosciences, Campus de Pedralbes, University of Barcelona, 08028 Barcelona, Spain
eDepartment of Geological Sciences, University of Florida, Gainesville, FL 32611-2120, USA
fIFREMER, GM, Laboratoire Environnements Sédimentaires, BP 70, 29280 Plouzané, France
gDepartment of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA), Jordi Girona, 18, 08034 Barcelona, Spain
hInstitut für Geowissenschaften, Christian-Albrechts-Universität zu Kiel, Ludewig Meyn-Str. 10, 24118 Kiel, Germany
Received 4 August 2008; 
revised 24 June 2009; 
accepted 27 July 2009. 
Available online 20 August 2009.

Abstract

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.

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Article Outline

1. Introduction
2. Gulf of Lions continental margin
3. Materials and methods
4. Results
4.1. Age model: synchronization of Mediterranean and Greenland climate records


5. Discussion




5.1. Formation of the Holocene condensed layer
5.2. Formation of condensed layers at times of high sea levels over the last 270 kyr
5.3. Constraints on condensed layer formation in the Gulf of Lions continental margin and global eustatic changes
5.4. Rapid flooding of the continental shelf during the longest interstadials of the last glacial period in Greenland


6. Conclusions


Acknowledgements


References









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