Mazovian Interglacial sites in the Sosnowica Depression and the Parczew-Kodeń Heights (Western Polesie, SE Poland), and their stratigraphic, palaeogeographic and palaeoenvironmental significance

We describe the geological context of the Pleistocene strata in the Sosnowica Depression and the Parczew-Kodeń Heights, as well as the main geological processes taking place in that area during the Middle Pleistocene. The stratigraphy of the Pleistocene succession is based on the analysis of new sites with Mazovian Interglacial deposits (MIS 11c) with age determinations obtained from palaeobotanical and palaeofaunal proxies, at Zahajki, Wygnanka, and Sytyta in the Sosnowica Depression, and Podedwórze and Gęś 3 in the Parczew-Kodeń Heights. The interglacial deposits documented occur in the direct subsurface and are not overlain by glacial deposits, which indicates that the study area was not covered by the ice-sheet of the Middle Polish Glaciations (Saalian, MIS 6). They are overlain by Early Liviecian (Fuhne, MIS 11b) lacustrine and bog deposits, or upper Vistulian (MIS 2) clastic and bog deposits. Holocene strata lie above. Therefore, the glacial deposits building the Parczew-Kodeń Heights are considered to derive from the Sanian 2 (Elsterian, MIS 12) Glaciation and not from the Saalian (MIS 6) Glaciation as previously thought. Palaeolakes formed in the late part of the Sanian 2 (Elsterian, MIS 12) Glaciation and remained open during the Mazovian Interglacial (Holsteinian, MIS 11c), with some still existing until the Early Liviecian (Fuhne, MIS 11b) Glaciation. The palaeolakes described were part of an extensive palaeolakeland of the Mazovian Interglacial, stretching from the southern part of Podlasie to the northern part of Western Polesie. The last ice-sheet in Western Polesie represented the Sanian 2 Glaciation.