An unusually long and continuous Late Quaternary sedimentary sequence has been preserved in a sedimentary basin formed in the Sokli Carbonatite Massif in eastern-central Finnish Lapland. A nearly complete sediment recovery from the central Sokli basin combined with palynological results from sediments not earlier recovered and an independent OSL/AMS 14 C chronology allow us here to define the Late Quaternary climate-stratigraphy at Sokli and describe in detail the environmental record. Three interstadial intervals of Weichselian age are distinguished that correlate with MIS 5c, 5a and part of MIS 3 in the marine oxygen-isotope record. The interstadials of MIS 5c and 3 age are here defined as the Sokli and Tulppio Interstadials, respectively. The MIS 5a interstadial is correlated with the Maaselkä/Peräpohjola Interstadials of Finnish Lapland, which previously have been tentatively assigned a MIS 5c age. Till beds in the Sokli sequence (deposited during stadials 3-1) correlate to MIS 5b, 4 and 3/2, respectively. Depositional environments and vegetational changes during the ice-free intervals at Sokli are discussed. The Sokli sedimentary sequence indicates significantly less extensive and more variable ice-cover over Finnish Lapland during the Weichselian than has been earlier suggested based on the long-distance correlation of litho-and bio-stratigraphic fragmentary evidence.
Traces of ice‐dammed lakes are found along the southern part of the Saariselkä mountain range. Various shore marks, outlet channels and fine‐grained sediments are indications of open water. The shallow basins were more or less filled by dead ice. At the beginning of deglaciation the meltwaters discharged over the mountain ridge to the north. As the ice margin receded toward the southwest new outlets were opened and the meltwaters discharged to the east and southeast. The ice‐dammed lakes existed and the deglaciation took place during the period 9,500‐9,300 B.P. The annual rate of retreat of the ice margin averaged 130–170 m per year.
An advanced method to study geomorphology of the well-known inselberg landscape in Finnish Lapland is introduced. Conventionally topographical maps and altitude reference produced from stereographic aerial photographs has been used. Now the LiDAR data has opened a new way to study geomorphology and terrain in detail. We applied the new methods in eastern Finnish Lapland from where seven inselbergs have been identified and analysed. With an accurate elevation data and images we could identify the detailed morphology in the inselbergs and examine the processes that actively alter the terrain. LiDAR data opened a view to the preglacial history and processes. Some preliminary estimations of the rate and amount of preglacial erosion could be made. It seems that erosion rate may have been in order of 2-10 m/Myr in Lapland based on existing datings and stratigraphic observations. Weathering and erosion history in Lapland is long as the kaolinite clays of Late Cenozoic, Mesozoic or even Mesoproterozoic in age are found in the weathered bedrock. Although all disconformities older than the Mesozoic era have probably been eroded to an unidentifiable extent, there is good reason to suppose that the main characteristics of the relief, including inselbergs, originated as early as the Late Cretaceous or at least in the Palaeocene.
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