AGE AND DURATION OF CRYSTALS GROWTH IN CHAMBERS OF VOLYN PEGMATITES (UKRAINIAN SHIELD)

Abstract

Formation of chamber pegmatites is associated with tectonomagmatic activation of the region of their distribution. It should be expected that the granitic chamber pegmatites of Volyn were formed by products of degassing of acidic magma. However, in the growth of quartz of the late generation, the beginning of crystallization of which was about 200ºC, CO2-fluids were involved. They are products of degassing of basic magma, which also took part in the growth of crystals at higher temperatures (˃573ºC). Crystallization of minerals in chambers was long: from 1.75±0.10 billion years (age of protogenetic inclusions of zircon and uraninite in topaz crystals) to 1.39 billion years (age of galena inclusions in late-generation quartz). So, for the first time, it was substantiated that the duration of crystal growth in the chambers of Volyn pegmatites was at least 360±100 million years. Therefore, it is assumed that the growth of crystals in chambers Volyn pegmatites lasted for quite a long time.