LATE GLACIAL ICE MARGINAL FLUCTUATIONS ON CENTRAL KOLA PENINSULA, NW RUSSIA

During the last glaciation, Kola Peninsula was covered by the northeastern sector of the Fennoscandian ice sheet. Based on the morphology and position of the Keiva moraines, along the southern margin of the peninsula, it has been suggested that a separate ice cap, the Ponoy ice cap, existed on eastern Kola Peninsula in late glacial time. In this study, where we have looked particularly at the distribution of end moraines and meltwater features related to the deglaciation, we cannot find evidence for such an ice cap. Rather, it appears that there was a steady retreat across the Kola Peninsula from east to west, with the highest parts of the landscape being deglaciated first. Extensive moraine systems and lateral meltwater channel series in the central part of the Kola Peninsula mountains, the Khibiny and Lovozero mountains, reveal a complicated interaction between regional ice sheet dynamics and local cirque glaciation. During the Younger Dryas, the eastern ice margin of the Fennoscandian ice sheet was positioned north-south across the central Kola Peninsula, depositing end moraines on the lowlands surrounding the mountains, particularly on the northern part of the peninsula. Within the central mountains themselves there is extensive evidence of ice marginal positions both from local mountain glaciation, such as regular end moraines at the mouths of cirques, and from continental glaciation, with inlet glaciers flowing up and into the valleys and cirques, depositing marginal moraines. Some cirque valleys have thick morainic deposits filling the floors of their innermost parts. These ‘cirque infills’ appear to have been deposited at the snout of inlet tongues of continental ice, much in the same manner as cirque infills are produced today in nunatak areas in Antarctica. A prerequisite for the formation of the Antarctic cirque infills is the presence of blue ice, and hence, high rates of evaporation directly from the ice. It is possible that blue ice conditions were also present during the formation of the Kola cirque infills, as no evidence of proglacial lakes is found in these cirques. This may offer insights into the Younger Dryas climate in nunatak areas just inside the marginal areas of northeastern Fennoscandian ice sheet.