ТИПОМОРФИЗМ ЦИРКОНОВ МАГМАТИЧЕСКИХ ПОРОД ЧАРКЫНСКОГО ВУЛКАНО-ПЛУТОНИЧЕСКОГО ПОЯСА

Abstract

The study and description of populations of zircons for the whole complex of volcano-plutonic rocks of the whole scope of Verkhoyano-Kolymsky Mesozoic formations has been carried out for the first time. The paper displays data on typomorphism of zircon populations and typomorphic peculiarities of composition of accessory zircons from subvolcanic and hypabyssal rocks of Charkynsky volcanic-plutonic belt (CVPB). Populations of zircons, divided by petrogeochemical parameters in three groups, confirm, by their characters and, in particular, by compositions of included zircons the previous petrologic conclusions about direct, or intermediate through contamination and fluids, participation of the mantle substance in formation of melts which have formed those rocks. This fact is indicated by the anomalously high ZrOi/HfOi ratios (~7S-60) in cores of accessory zircons from the main CVPB basic rocks. Similarity between compositions (with the high ZrCVHfO} ratios) of priming-cores and the morphotype Qs zircons from the host rhyodacite nappe (the upper Bezymyanninskaya formation) allows to assume the single long living source as for melts having formed the host volcano-sedimentary formation, so for melts having formed intrusions of the volcano-plutonic belt.