High-fractionation granitoids of Pschish rare metal of district the Northern Caucasus

Abstract

Relevance. The different type of granitoids various ages and composition described on the Northern Caucasus. The Late Paleozoic stage of forming Central megablock Greater Caucasus has significant meaning in forming granitoids magmatism and it metallogeny. The igneous magmatism of Pschish ore district did not receive illuminating in geological literature but ore mineralization of strategic metals of beryllium, tantalium, niobium, tungsten, lithium with it related. The aim of the study is to receive complex petrological and geochemical characteristics of ore generating of ulra acidic granitoids and its typization on the modern level. Objects of researching werechoose an epithermal deposits and manifestations gold-silver types in all tectonic zones of region. Materials of researching. Materials, using in paper, received by of author in process carrying out of prospecting, prospecting-estimation, geology-survey (1:50000) and special metallogenic researching that it conducted from 1967 year on the Greater Caucasus. Methods. Methods of study except of geological and petrographic of description of felsic granitoidsand include receiving quantitative characteristic of composition rocks. Thesilicateanalysis of rocks on the basic components determined by roentgen spectral fluorescent method, Co, Ni, Zn, Pb, Li, Sc, Cu – by ISP-AES, the other elements and REE – by method ISP-MSin Laboratory of Institute of Mineralogy, Geochemistry and crystal chemistry of rare elements (c. Moscow). Results. New data received on typezation of petro-geochemical silica-acid magmatism of Pschish areal with detach of two phase intrusion: two-mica leucogranites and leucotranites. Dikes of greisenization leucogranites and ongonitesdiscernedso. All intrusive derivates of Pschish areal generated by melting of felsic pellites lower crust and carry to high fractionation differences forming of its took place crystal-fractionation of feldspars, hornblende, and so accessory minerals – apatite, allanite, monazite. Two types tetradiceffectfractionationofrareearth elements М – and W- types display in rocks. Thephysic-chemistryconditionschange and it lead to preferable of enriching fluids of ore components in conditions rise of alkali environment.