Late Weichselian glaciation, postglacial relative sea level and paleoenvironment, north-central Kola Peninsula, Russia

This study provides new data to constrain the nature of Late Weichselian glaciation, postglacial relative sea level and paleoenvironment of the north-central Kola Peninsula, Russia. The Kola Peninsula is strategically located to resolve uncertain glacier reconstructions in the southeastern Barents Sea region. Stratigraphic and geomorphic records are investigated on the Murman coast from the Voronya River to the Vostochnaya Litsa River. These records include: (1) sediment cores recovered from emerged coastal lakes, (2) raised marine sections, (3) glacial and coastal landforms, and (4) ice-flow-direction indicators.; Basal radiocarbon ages from two sediment cores indicate deglaciation of the area prior to 11000 yr BP. Glacial striae are consistently oriented toward the NNE, reflecting ice flow from the central Kola Peninsula toward the Barents Sea. Two prominent shorelines descend eastward along the Murman coast. Trends in shoreline elevations and ice-flow-direction indicators suggest the greatest regional Late Weichselian glacier load over the west-central Kola Peninsula rather than in the southern Barents Sea. Radiocarbon ages associated with the marine-lacustrine sediment transition in four cores and twelve radiocarbon ages from raised marine sections provide age control of the relative sea-level record. The emergence above sea level of basins at 41 and 54 m a.s.l. brackets the age of the upper shoreline (locally 48 m a.s.l.) between ca. 10300 and 10500 yr BP. The lower shoreline on the Murman coast is associated with a transgression dated to 6200-6600 yr BP, correlative to the Tapes shoreline in Norway. Glacio-fluvial terraces and deltas associated with the upper shoreline on the Murman coast indicate remnant glaciers on the north-central Kola Peninsula during the Younger Dryas.; Each of the investigated sediment cores exhibits a transition from dominantly marine and brackish to dominantly lacustrine diatoms. The nature of this transition varies with basin physiography and age of emergence above sea level. Changes in lacustrine diatom assemblages in a core from a lake 54 m a.s.l. indicate a general trend toward more oligotrophic conditions during the Holocene. A relatively abrupt transition in diatom flora occurs between ca. 4000 and 5000 yr BP, consistent with an interval of climatic cooling inferred in terrestrial and marine environments in Scandinavia and the Barents Sea region.