Revision of the late Middle Pleistocene stratigraphy and palaeoclimate in Poland.

The aim of this paper is a critical verification of the late Middle Pleistocene stratigraphy in Poland in connection with stratigraphical schemes in the neighbouring countries. Although a terrestrial record of the Middle Pleistocene is almost complete in western and southern Europe, it is full of gaps in central and eastern Europe. Eight key sites in Poland and one in Belarus were selected to compile environmental and palaeoclimate data for a revised stratigraphy from the termination of MIS 12 to MIS 6, and the chronology was based on correlation with oxygen isotope stratigraphy and OSL ages. The late Middle Pleistocene record starts with the Holsteinian lake sequences, some of which have been initiated already at the end of MIS 12, persisted through MIS 11 and terminated in mid-MIS 10. In the examined sites, MIS 11 is represented also by deposits of meandering rivers in a temperate climate. In contrast, there is no evidence for deposition in most of MIS 10 and in MIS 9. A warmer and presumably wet episode at the beginning of MIS 8 lead to local erosion, followed by development of small lakes. Modest ice sheet advance into central Europe occurred in the second part of MIS 8, as reflected by a till, glaciofluvial and glaciolacustrine deposits and presumably, also by permafrost and ice wedges in western Belarus. MIS 7 seems to have been generally warm and wet when small lakes and meandering rivers could develop. Such mild conditions were interrupted with cool and probably drier episodes when braided rivers and limited pedogenesis occurred. Saalian ice sheet cover of central Europe in MIS 6 was widespread, but even more importantly, in this stage periglacial environments were dominant, as shown by continuous permafrost, intensive aeolian activity and development of ice wedges and involutions. Braided rivers developed during short wetter intervals. [ABSTRACT FROM AUTHOR]