The Crust and Upper Mantle (Tectonosphere)

Abstract

Everything known about tectonic, magmatic, and metamorphic phenomena indicates that they are directly linked with processes taking place within the Earth’s crust and the upper mantle. It is in these envelopes that the direct causes of endogenous phenomena are concentrated. The significance of processes taking place at greater depths is not yet clear. It may be that it is very great; as we have seen, there are grounds for supposing that all the Earth’s envelopes are involved in gravitational differentiation, which is the main source of energy for geological processes; these deeper processes, however, do not affect the surface directly but through the upper mantle and crust. They also give rise to movements in these envelopes and to transformations of matter that themselves lead directly to tectonic, magmatic, and metamorphic phenomena on the surface. Because of this role of the upper mantle and crust, it has been suggested that they should be joined together under the common title of the “Earth’s tectonosphere”.