Gravity flows in late quaternary deposits of the north-western Russia (Kola Region) and their possible relationship with pleistocene earthquakes

The lithological features of Late Quaternary deposits formed during the marine isotope stage MIS 3 in the Ura River valley on the Barents Sea coast of the Kola region (North-Western Russia) have been studied. Seismically induced structures were revealed and preserved in sandy-clayey sediments in the form of five deformed SSDS layers separated by undisturbed deposits. These layers include load casts, flame structures, injections, sedimentary breccia, and folds. The SSDS were formed because of several reasons, i.e., debris flows originated from the shear tensions in sub-aqueous settings, pressure of the overlying deposit weight, and liquefaction. Seismic shock and aftershocks would have served as the most possible trigger to spread the gravitational flow activity and initiate the processes of liquefaction and fluidization. The seismic waves may have been caused by the tensions at the front of the advancing Weichselian Ice Sheet in MIS 2. We consider the reactivated large Karpinsky oblique-slip fault separating the Baltic Shield from the Barents Sea Plate as a main seismogenic zone.