Profile of Orogenic Belts

Published by the American Geophysical Union as part of the Geodynamics Series.

Working Group 9 undertook a study of the relationships between different types of endogenous, i.e. tectonic, magmatic and metamorphic, processes on continents. These relationships could be expressed in the form of spatial and time correlations of the indicated processes. All previous geological experience confirms the existence of these correlations. For example, the development of geosynclines proceeds in a rather definite succession of endogenous processes: dominant crustal subsidence accompanied by the emplacement of basic and ultrabasic magmas, is followed by an epoch of formation of granites, regional metamorphism and folding, after which orogenesis sensu stricto sets in. The ancient platforms have entirely different, quiescent conditions of deep processes. There are rift zones with their peculiar structure and specific magmatism. Unusual combinations of endogenous processes are found on continental margins, in transition zones from continents to oceans.