DEEP GEOSPHERES AND ORE GENESIS

Abstract

This paper addresses the problems of ore metal mobilization and concentration and volatile component behavior in the Earth's mantle. Diamond crystallization and the formation of chromitite bodies upon interstitial melt infiltration in mantle rocks are examples of mineralization processes occurring in the Earth's mantle. Depending on the formation conditions, mantle magmas can be intrinsically enriched in various ore components (PGE, chromium, and rare metals). Their further concentration occurs in crustal magma chambers as a result of the processes of magma mixing, prolonged crystal fractionation, and the separation of immiscible salt melts (mainly carbonatitic) at late stages of the magma system evolution. In subduction zone regions, ascending flows of deep-derived fluids selectively transport a number of ore metals into the growing continental crust and prepare continental crust material as a source of the material of ore deposits. It is possible that some of these fluids took part in the formation of certain deposits. In hydrothermal ore-forming systems with non-magmatic sources of metals and solutions, the source of heat energy was most likely represented by magma masses intruded into the upper crust.