LATE PLEISTOCENE AND HOLOCENE ENVIRONMENTAL CHANGES IN NW SPITSBERGEN – EVIDENCE FROM LAKE SEDIMENTS

Late Pleistocene and Holocene Environmental Changes in NW Spitsbergen – evidence from lake sediments. - Subbottom profiling and coring in the two proglacial lakes Varfluesjoen and Vogtvatnet (NW-Spitsbergen, Andréeland) show a continuous record of lacustrine sediments underlain by marine sediments and finally till/bedrock forming the base. The sediment source for the marine sedimentation in the lake basins is primarily found in the inner fjord areas of Wood- and Wijdefjord whereas the lacustrine sedimentation is fed by the local tributary.

According to 14C data, sedimentation in the lake basins starts around 12.0 ka BP in both investigated lakes. The separation of the lake basins from the Fjords, marked by the marine – lacustrine boundary in the sediments, happened around 9.7 ka BP in Varfluesjoen and around 7.9 ka BP in Vogtvatnet. This difference in time is explained by different elevations of the basin thresholds. According to this difference of the two near by situated lakes an approx. relative uplift rate of 1,7 cm/a can be calculated for this timespan for the northern Andréeland area.

14C data show that the sedimentation in the lake basins starts after deglaciation at 12.0 ka BP. The sedimentary record shows in both lakes at least one prominent glacier readvance around 8.0 ka BP and several younger minor glacier fluctuations. Older Late Glacial readvances of the glaciers where not detected in the lake basins. Further marine ingressions after separation from the fjordsystem where only detected in Vogtvatnet, indicating only minor changes in relative sea level since the Boreal.