The Pleistocene contribution to the net erosion and sedimentary conditions in the outer Bear Island Trough, western Barents Sea

Abstract

The Pleistocene sedimentary conditions and the glacial contribution to net erosion were determined for the outer Bear Island Trough by using a Monte Carlo-type method. The approach uses ages for glacial/interglacial periods that were based on the regional ice-sheet volume curve. The results indicate that the western Barents Sea was glaciated during four marine isotope stages: MIS 16 (635.6–624.7 ka), MIS 12 (438.7–428.0 ka), MIS 6 (138.6–134.6 ka) and MIS 2 (19.3–16.0 ka) for a total duration of 29 ka. The first glacial event (before 440 ka, MIS 16) resulted in homogeneous erosion over the study area (with an erosion rate of 24.2 ± 8.5 mm/a). After 440 ka, a change in sedimentary conditions resulted in inhomogeneous erosion rates over the study area from −12.6 ± 1.6 (i.e. net deposition) to 1.6 ± 1.8 mm/a (i.e. net erosion). The most likely values of average deposition rates during interglacial periods were modelled as 0.12 ± 0.1 mm/a. In the outer Bear Island Trough the net erosion was found to be mainly the effect of tectonic uplift and subsequent erosion prior to the glacial ages. The results show that in most parts of the study area the Pleistocene glacial contribution to the total net erosion was small: the most likely glacial contribution in the eastern part of the area reaches 100 m, which is about 9 % of the total net erosion, while in the westernmost part the glaciations did not contribute to the net erosion.