Происхождение магм и вулканических взрывов в океанических и субдукционных областях с учетом данных о горячей гетерогенной аккреции Земли

Abstract

The obtained numerous proofs of hot heterogeneous accretion of the Earth and the calculated quantitative models of magmas lead to a fundamentally new solution for the genetic problems of magmatic petrology. They indicate the formation of geospheres and the initial substance of magmas resulted from fractionation of the global magmatic ocean, which arose as a result of a huge impact heat release during mantle accretion. Due to the increase in temperature as accretion progressed, a reverse geothermal gradient first existed in the mantle, and on the early Earth there were no modern geodynamic conditions. The gradual warming of the mantle by the initially very hot core led to the formation of a direct geothermal gradient and convection as well as oceanic and subduction regions in the Neoproterozoic. In the oceans, magmas are formed as a result of decompression melting during the surfacing of eclogite lenses, which emerged by way of filling impact craters with melts of the synaccretionary magmatic ocean. Magmas of subduction regions are the result of frictional melting of the magmatic ocean differentiates. Volcanic explosions occur under the influence of high pressure of the gas phase preserved by decompressional solidification of magmas at the shallow stage of ascent.