Литосфера (Aug 2018)
Rheological model of Earth’s crust (model of third generation)
Abstract
Introduction. The ground of the rheological Earth’s crust model with a barrier zone between its upper and middle parts is given. The zone is impermeable to fluids radically changes present-day understanding of the upper part lithosphere structure. A critical generalizing review for, earlier models of the continental crust structure and geological nature of K1 geophysical interface, which proposed by different authors, are is commited for consideration. Metods. The information regarding the middle crust watering is presented. The data on electromagnetic deep probing indicate that in the middle and lower crust and, possibly, in the upper mantle the content of free water makes up about 1% in volume. Therefore, there is some kind of block which does not allow for the whole water to squeezed up into the upper part of the Earth’s crust, where an open crack-pore space is filled with water under hydrostatic pressure. So, clearly expressed hydrodynamic zoning exists in the continental Earth’s crust. This universal continental Earth’s crust zoning now is confirmed by geophysics and super-deep drilling, but it is not yet enough realized by a great number of geologists and geophysicists. Discussion. In the upper crust the rocks become harder with deepening, as the effective pressure increases and stronger and stronger press down them. Geophysical studies mark this fact by the growth speed of seismic wave spreading and the decrease of electrical inductance. Lower of the pores and cracks closing horizon (lower of the barrier) the picture sharply changes. Effective pressure is falling and rocks lose fully their hardening, becoming even less hard than at the day surface. Consequently, lower of the hardest upper crust bottoms under a dense impenetrable zone extremely weakened water-containing rocks are located. The earth crust turns out to be sharply stratified into (zones) not only by the water-presence, but even more contrastingly - by rheological (hardening) properties. At any even miserable mechanical movements and deformations at the boundary of hard and weak storeys disruptions and motions is inevitably occured. Conclusions. The importance of suggested model of the crust structure for the tectonics, petrology, ore-formation, hydrogeology, oil geology, seismicity as well as for the nuclear wastes and others is considered.
Keywords
