ABSTRACT
The presence of high-temperature ultrabasics in the earth’s crust in volumes of mantle plumes indicates their particularly high degree of thermal activation of the asthenosphere, associated with inflow of a large quantity of heat, which in such cases can enter only from below from deeper zones of the earth. The formation of a megadome creates a tensile environment, which induces regeneration of older faults and origin of synchronous faults. Negative tectonic structures such as grabens, aulacogens and rifts are associated with them. Magmatism in the latter depends on the depth of penetration of escape fractures and their opening of ultrametamorphic chambers, which are apparently the result of conductive heat transfer over the temperature-activated asthenoregion. The isobaric nature of metamorphism suggests temperature as an active factor. Metamorphism in protogeosynclines is also of a regional nature but its isotemperature form is also directly related to the energy supply from the asthenoregion.
