Geodynamics of Eurasia: Plate Tectonics and Block Tectonics

摘要

The analysis of information on seismicity, active faults, and satellite measurements taken from geological and geophysical databases of the electronic geodynamic globe shows that only the northern part of the Eurasian lithospheric plate should be regarded as an independent and relatively indivisible lithosphere unit. We defined it as tke North Eurasian plate that moves as a whole eastward with a clockwise rotation. The smaller blocks surrounding this plate in the south and east (some of which are commonly referred to as microplates) reveal local divergences in the velocities and vectors of their displacements in ITRF system. The seismotomog-raphy results and prevailing depths of earthquake hypocenters suggest that most of these structures are relatively shallow-seated and bounded from below by detachment zones localized at the crust base or within the lithosphere. The present-day geodynamic discreteness of the continent is controlled by its preceding evolution," which predetermined a kinematic competence of various structures, and by the current interaction of plates and blocks within Eurasia and at its margins. The evidence presented indicates a multilevel character of block motions and confirms the idea of lithosphere lamination.