Palaeoenvironmental implications from Lower Volga loess - Joint magnetic fabric and multi-proxy analyses

Abstract

Magnetic fabric (MF) investigations complemented by geochemical and grain surface analyses of the understudied and controversial marine isotope stage (MIS) 5 b, 4 and 3 loess deposits in the Lower Volga region, Russia show that the material has been transported and deposited by wind and to a large extent experienced post-depositional reworking. Grain surface features suggest that the material was glacially ground and fluvially transported prior to final aeolian deposition as loess. Secondary magnetic fabrics in the loess reveal pedogenic and cryogenic processes and a generally cold environment with brief shifts to warmer climate during late MIS 5 and MIS 3. Palaeowind reconstructions derived from preserved primary aeolian MF, indicate locally influenced westerly and north-westerly flow as part of a wider scale westerly wind pattern, similar to modern day winter conditions. We suggest that the climate of the last glacial in the Northern Caspian Lowland was cold and dry, with higher windspeeds and less variability during MIS 4 compared to MIS 3.