Earth’s crust

The very important to develop geodynamical models of the Earth’s structure defining corresponding state equations and flow equations for the fragments of mantle with big vis-cosity and inhomogeneous density distribution and nonlinear interaction with other frag-ments of the mantle and the crust. It is substantiated the importance and advisability of transition to generalized models of medium and processes which define the dependence of geophysical and geodynamical processes from thermodynamical parameters of Earth’s crust.

The modern concept of the deep structure of the crust of Onega structure and its surroundings is given based on analysis of available geological and geophysical data and the drilling record for the Onega parametric borehole obtained in the past fifty years. The deep structure of the Earth’s crust of this territory was studied in more detail and its composition, possible geological nature and geodynamic setting were assessed more accurately by summing up and interpreting of geological, tectonic, geophysical and mineralogenic data.
 

In the resent years fragmentary crustal low velocity zones were revealed by DSS profiles at depths of 3-25 km around the Earth. In most cases they are considered as thermodynamical phenomena rather than a result of changing composition when mineral material is transformed by pressure and temperature at the depth of their occurrence. Multimethod laboratory studies of sample show that under PT conditions at 5-15 km depths rocks are subjected to cataclastic and dilatational changes.