NEOARCHEAEAN (2.60 GA) REACTIVATION OF SHEAR ZONES AND OROGENIC GOLD SYSTEMS IN THE WESTERN SEGMENT OF THE VODLOZERO TERRANE

Abstract

Zircons from the Mesoarchaean chemically precipitated silicites of the Koikary structure (central portion of the Mesoarchaean Vedlozero-Segozero greenstone belt, western margin of the Palaeoarchaean Vodlozero block), located in the area affected by a large regional shear zone, were studied. Auriferous ore mineralization, associated with the tectono-metasomatic activation of the territory, was identified in the structure. The mineralization is represented by consecutively forming assemblages (pyrite-pyrrhotite, NiCo-sulphoarsenide, Ni-sulphide, copper-base metal-sulphide, bismutotelluride-noble metal). The ore mineralization was formed at temperatures varying from 500 °C to 140 °C. The study of zircons from the Mesoarchaean silicites has made it possible to determine their primary hydrothermal nature and to date them at 2.60 Ga. The age obtained is regarded as the activation stage in the formation of a polychronous regional shear zone in the western segment of the Vodlozero terrane which gave rise to ore systems.

Keywords

• архей
• цирконометрия
• сдвиговые зоны
• рудные системы
• водлозерский террейн