Eurasian contribution to the last glacial dust cycle: how are loess sequences built?
- 1Ecole Normale Supérieure, UMR CNRS 8539, Laboratoire de Météorologie Dynamique, and CERES-ERTI, 24 rue Lhomond, 75231 Paris CEDEX 5, France
- 2Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA
- 3Centre for Ice and Climate – Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen OE, Denmark
- 4Physics Institute, Climate and Environment Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
- * Invited contribution by Denis-Didier Rousseau, recipient of the EGU Hans Oeschger Medal 2017.
Abstract. The last 130 000 years have been marked by pronounced millennial-scale climate variability, which strongly impacted the terrestrial environments of the Northern Hemisphere, especially at middle latitudes. Identifying the trigger of these variations, which are most likely associated with strong couplings between the ocean and the atmosphere, still remains a key question. Here, we show that the analysis of δ18O and dust in the Greenland ice cores, and a critical study of their source variations, reconciles these records with those observed on the Eurasian continent. We demonstrate the link between European and Chinese loess sequences, dust records in Greenland, and variations in the North Atlantic sea ice extent. The sources of the emitted and transported dust material are variable and relate to different environments corresponding to present desert areas, but also hidden regions related to lower sea level stands, dry rivers, or zones close to the frontal moraines of the main Northern Hemisphere ice sheets. We anticipate our study to be at the origin of more sophisticated and elaborated investigations of millennial and sub-millennial continental climate variability in the Northern Hemisphere.