Block structures of the Kola peninsula, their resistance under the conditions of natural and technical systems (by the example of the Khibiny and Lovozero mountains)

The Kola Peninsula has a block-structure pattern caused by the interaction of main geodynamic processes: continental drift, tectonic activity, and elastic resistance of rocks. The multirange morphotectonic blocks reflected the youngest tectonic structures of the Kola Peninsula and of the mountain massifs Khibiny and Lovozero as the key objects were identified with wide-using morphometric methods. Position location of the blocks' borders (tectonic zones) and their ranging were recognized by lineament analysis of valleys and tectonic faults presented in relief. The results were checked with aerial photo and satellite images and verified during field-work fixing their geological and landscape features. The discrepancy of the large- and medium-sized geological structures and land forms is established. The low-strength rocks correspond to the highest topographic forms, and the high-strength rocks - to the lowest ones. Geodynamic deformation of the topography surface is reflected in conditional amplitudes of the ascending of different morphotectonic structures. Determined conditional amplitudes are reached 1000 m. From the numerical simulation of stress state of the crust the regularities of stress distribution in the rock massifs depending on relief and lithospheric plate movements have been established. It has been determined the horizontal stresses are concentrated beneath the valley bottoms (beneath the enveloping base surface of relief), and within the uplands they decrease in comparison to applied tectonic stresses. The vertical tectonic stresses are tensile within the uplands and they are compressive beneath the valleys. Combined effect of the gravitation and of the horizontally oriented tectonic forces causes the interrelated lifting and lowering of the blocks - the valley areas are "sinking" and interfluve areas are "floating" relatively to the general rising of the Baltic shield. Stability of the block structures and resistance of natural-engineering systems (mine workings, quarries, etc.) distorted the gravity equilibrium because mining operations depend on tectonic pressing at a depth and expanding at the block lift accompanied with the stress redistribution within rock massifs.