Title

N. I. Gusev, A. I. Gusev, S. P. Shokalsky, S. V. Kashin, A. N. Larionov, E. V. Tolmacheva

Mezozoic tectonothermal activisation and epithermal mineralization in the North-Eastеrn Gornyi Altai

Silver-gold mineralization of the site Churya in the North-Eastern Gornyi Altai connected to explosive breccias in the exocontact zone of subvolcanic rhyolite with age (SHRIMP II) 390 Ma. Ore mineralization refers to the gold-mineral type (Au:Ag = 1:10) of adularia-sericite (low sulfidation) epithermal family and was formed by the collapse of colloidal solutions. The mineralized phreatomagmatic breccias contain along with Devonian zircon (400 Ma), as more ancient (462– 2559 Ma) and young zircon, submitted by the five age groups: 359, 349, 327, 285 and 126 Ma. Cretaceous zircon contains inclusions of silicate melt and volcanic ash, indicating its crystallization in the gas-fluid environment in the process of breccias formation. Mineralization of Churya site refers to morphological type of mineralized explosive pipes.
Key words: : Gornyi Altai, Churya gold site, phreatomagmatic breccias, mineralized explosive pipes, Ag-Au epithermal mineralization, zircon U-Pb age SHRIMP II