Granulite-gneiss (high grade) belts: geodynamic view

Abstract

On the basis of analysis and generalization of modern data the features of the structure and tectonic evolution of granulite-gneiss (high-grade) belts of the Earth are considered. Their continental collisional tectonic nature, polycyclic and inherited character of development, expressed in repeated manifestations in the same belt of several stages of granulite metamorphism, separated by intervals of several hundred million years, are confirmed. Granulite-gneiss belts are permanent mobility structures that maintain endogenous activity in all stages of their existence, including intraplate environments. The relationship between high-grade belts and supercontinental cyclicity is revealed, which is expressed in the spatial coincidence of the majority of them to the outskirts of the young oceans that arose during the breakup of Pangea; in the control of assembly and breakup of ancient supercontinents along granulite belts; in correlation of manifestations of different types of granulite metamorphism in these belts with the stages of the supercontinent cycle. In the evolution of these belts there is a complex interaction of plate-tectonic and mantle-plume mechanisms, which is expressed in the combination of continental collision and underplating processes. The possibility of using granulite-gneiss belts in paleotectonic analysis along with other indicators of geodynamic settings is shown.