LOESSFEST'09 | Aug. 31st – Sept. 3rd, 2009 |Novi Sad-Serbia
Long Term Seasonality Changes and Abrupt Climate Shifts Recorded in Highly Resolved Dust/Loess Sequences Across Eurasia
Machalett, B.1,2, Oches, E. A.2, Markovic, S. B.3, Mavlyanova, N. G.4,
Endlicher, W.1
1Humboldt-University of Berlin, Department of Geography, Unter den Linden 6, D-10099 Berlin, Germany;
2Natural and Applied Sciences Department, Bentley College, Jennison Hall 126, 175 Forest Street, Waltham, Massachusetts 02452-4705, USA
3Chair of Physical Geography, Faculty of Sciences, University of Novi Sad, Serbia
4G.A. Mavlyanov Institute of Seismology, Uzbek Academy of Sciences, Tashkent, Uzbekistan
The distribution of Eurasian loess deposits allows interregional palaeoclimatic investigations along a west-east transect across the entire Eurasian loess belt of the Northern Hemisphere, offering the potential to reconstruct Pleistocene atmospheric circulation patterns and aeolian dust dynamics on a wide spatial scale.
High resolution particle size analyses from several loess sequences across Eurasia (Serbia, Romania, Uzbekistan & Kazakhstan) provide a detailed signal of glacial-interglacial atmospheric dynamics and long term, semi-continuous trends in the aeolian dust record since marine isotope stage 10. In consideration of the modern synoptic atmospheric circulation patterns and aeolian dust transport across the Eurasian landmass, we propose that the observed proxy data reflect oscillations superimposed on a long term signal of seasonality, triggered by changes in duration and permanency of the seasonal shift of the Eurasian polar front during the middle to late Pleistocene. As the activity of the polar front jet is intimately connected with the high level planetary frontal zone (HPFZ), the Eurasian loess archives may also serve as a recorder of inter-hemispheric climate connections in past atmospheric circulation.
Unlike the similarities in long term seasonality changes across Eurasia, there are distinct differences in short-term climate variability along the studied transect from SE Europe to Central Asia. While the records in SE Europe seem to reflect short term climate oscillations controlled by regional climate dynamics and local wind systems, the highly resolved Central Asian dust archives suggest a clear pattern of rapid warming and gradual cooling.
This study aims to reconstruct long-term aeolian dust dynamics and climate variability recorded in high-resolution loess records across Eurasia, linking interhemispheric climates on time scales ranging from glacial-interglacial to (sub)millennial.