Mineral Composition and PT- Conditions of the Formation of Ca-Mg-Fe Metasomatites in Basic Granulites (Por'ya Guba, Belomor'e): Evidence for Syngenetic Granitization and Basification

摘要

One of the least studied problems in the petrology of granite gneiss and migmatite complexes is the forms and scales of transport of significant amounts of Mg, Fe, and Ca being removed during granitization and debasification of metamorphic rocks [ 1]. At present it is not clear when most of the removed elements are dispersed outside granitization aureoles and when their concentrated reprecipitation with the formation of specific melanocratic rocks (basificates) occurs. There is still no evidence for a genetic link between granitization and basification. Sparce data on the compositions of minerals from basificates, their relationships [2, 3], the PT-parameters of the formation [4], and the absence of information about parental fluids do not allow us to discuss the ways of matter migration, the distance and direction of transport, and causes of reprecipitation of not only major, but some ore and minor elements as well.