Content and Composition of Rock Debris at Lomonosov Ridge (83° N): Indication of Palaeoenvironmental Changes

The results of studying the quantitative, material, and morphometric composition of rock debris in sediments sampled by a box-corer on Lomonosov Ridge (83° N), Arctic Ocean, during the Severnyi Polyus 41 expedition of the Arctic and Antarctic Research Institute are presented. Clasts ≥ 1 cm in size were sampled from each distinguished layer according to the lithological description. The age model was created by the lithostratigraphic correlation with previously dated cores. The content of clasts on the eastern slope and summit is significantly higher than on the western slope, which is explained by the higher sedimentation rate on the western slope after the deglaciation peak. The change in the rock composition from carbonate to igneous and the increase in roundness with time indicate a higher input of Eurasian material in MIS 1.