Merkine˙ (Eemian) Interglacial deposits in the Vilnius region and the limit of the last glaciation in southeastern Lithuania

Merkine (Eemian) Interglacial deposits in the Vilnius region (southeastern Lithuania) were detected in more than 30 boreholes during geological mapping, and investigated by pollen analysis and lithological methods. These deposits were found in small kettle holes in the Medininkai upland and are present in the form of lacustrine sediments. The Interglacial sediments of the Medininkai upland are covered by Nemunas (Weichselian) deposits of nonglacial origin. Pollen analysis of the Upper Pleistocene section from the Medininkai locality (borehole 117) shows the Merkine Interglacial and several intervals with different climate oscillations during the Nemunas (Weichselian) glaciation. The Merkine Interglacial deposits in the adjacent Vilnia-Neris depression (north of the Medininkai upland) were formed in a large lake and represented by silts, sand and freshwater marl. They are covered by Early and Middle Nemunas lacustrine and Late Nemunas glacial deposits. This palaeo-lake played a role as the local basis of erosion during the Merkine Interglacial in the Vilnius region. The occurrence and distribution of Merkine Interglacial deposits provide sufficient reliable evidence to establish the position of the maximum extent of the Nemunas ice sheet and to allow investigations of climate history during the Weichselian glaciation. The reconstructed palaeohydrographical network of the Merkine Interglacial in the Vilnius region shows a pattern which is significant for palaeoenvironmental interdisciplinary studies of this Interglacial.