A catastrophic holocene event in the lake bottom sediments of the Kola region (northeastern Fennoscandian shield)

Horizons with seismogenic sediments are revealed in the bottom sediments of the lake basins in the southwestern Kola Peninsula. In the borehole cores, they are represented by material that sharply differs from the overlying and underlying sediments: fragments of gyttia, siltstone, wood, sand, and peat that are embedded in the sapropelic matrix and look like breccia. These sediments reflect a strong catastrophic event from the Holocene that occurred 6000–5400 14C yr BP. The seismic events that happened in the middle Holocene in the northeastern Fennoscandian shield indicate a significant role of the tectonic component in the damping process of relaxation of the Earth’s crust in the unloading of the recent glacier cover.