ON THE AGE AND EXTENT OF THE MAXIMUM LATE PLEISTOCENE ICE ADVANCE ALONG THE BALTIC-CASPIAN WATERSHED

Abstract

In northwestern European Russia glacial limits are determined using both geomorphological and stratigraphical criteria. Until the late 1940s there was general agreement that a single Valdaian glaciation had followed the single Late Pleistocene interglacial. However, in 1950 Moskvitin suggested that a Mologa–Sheksna interglacial divided the large, Valdaian ice age into two glaciationsthe Kalinin and Ostashkov. Another long-standing controversy concerns the extent of the two ice advances, namely, which ice sheet, Early or Late Valdaian, was larger and where the major ice limit was located. These disputes largely stemmed from the controversy concerning the origin of the sediments overlying the Mikulino interglacial sequences. In standard maps of the Geological Survey the thin discontinuous diamictic mantle is usually not regarded as a reliable signature of an ice advance. In the digital map such sequences of Mikulino and Valdai interstadial sediments are also shown as not overlain by till. Accordingly, the limit of the maximum Late Pleistocene ice advance is located distally but close to the main marginal belt comprising diverse hummocky glacigenic accumulations. However, the geomorphological evidence is not straightforward everywhere.