Middle and Late Pleistocene stratigraphy, chronology and glacial history in Finnmark, North Norway.

Abstract

The Pleistocene superficial deposits in Finnmark, North Norway, were investigated in about 250 excavations and drillings during the period 1960-1990. Based on this regional background data six localities on Finnmarksvidda and two localities on Varangerhalvøya were selected for more detailed stratigraphic work. This paper presents results from the key localities Vuolgamasjohka, Vuoddasjavri and Sargejohka between Kautokeino and Karasjok on Finnmarksvidda, and additional data from the Karasjok area (Balucohka, Gamehisjohka and Buddasnjarga), and along the eastern coast of Finnmark on Varangerhalvøya (Komagelva and Leirelva).Pre-Quaternary weathered bedrock characterises the subsurface in many topographical depressions on eastern Finnmarksvidda, for example at Sargejohka. Weathered bedrock is also recorded in some plateau areas in the same region. The Pleistocene stratigraphy in Finnmarksvidda extends from at least 300 ka ago the present. It includes paleosols, waterlain sediments and tills from at least seven glaciations during the last three major glacial 100 ka cycles.The glaciations shifted between configurations with ice-centres located inland south and southeast of Finnmarksvidda (Fennoscandian ice-sheet configuration) and with ice-centres in the mountain range in the west (Scandinavian ice-sheet configuration).