Geophysical processes and biosphere: article

Аnnotation: In the area of the village Loukhi the open pit mine studied, which reveals cross-section a radial kame ridge composed of horizontally layered lacustrine sands with cross-bedded sand lenses and interlayers of siltstone, in which developed convolutions with a thickness of up to 0.2-1.2 m in the form of wide synforms, narrow antiforms and pseudonodules. Lacustrine sediments are covered of sand-gravel sediments with paleosols passing down the slope of the ridge into moraine boulder sands, under which the layers are heavily dislocated. The objectives of the work were to analyze the conditions for the formation of kame and deformation structures in its section, as possible indicators of paleoseismicity. For an explanation tructural features of the section, a ridge formation scheme is proposed as a result of projecting on the basic moraine the sediments of a flowing subglacial lake that opened up at the beginning of their accumulation in the body of the glacier during the deglaciation. Structural analysis of reverse faults in dislocated sediments proves their gravitational nature, which is not associated with glaciotectonics, which indicates the immobility of the ice mass. Convolutions are developed in layers of a narrow granulometric range (fine-grained sands and silts), which strongly distinguishes them from seismites in lacustrine sediments of highly seismic regions. Therefore, these structures are not associated with seismic liquefaction of sediments, despite the location of a section at 40 km from the southwestern board of the Kandalaksha graben, where 8-points Holocene paleoearthquakes of moderate magnitudes were detected. This fact does not confirm the possibility of the occurrence of seismic events with M ≥ 6-6.5 in the Late Glacial period in the study area.