The Intrusive Phase in the Evolution of a Volcanic Structure and of Au–Ag Low Sulfidation Mineralization: The Nevenrekan Deposit, Magadan Region, Russia

Abstract

This paper provides information on the structural setting and ore composition of the Nevenrekan deposit. We provide an account of the regional and local factors of mineralization control. The ore bodies are confined to the junction between regional faults and annular ruptures of a circular subsidence. The geochemical zoning of the ore field is disturbed. We show how geochemical associations are distributed in the ore zones of this deposit. The structural geological and geochemical data, as well as results from a comparison among the Au‒Ag low sulfidation (LS) deposits at the Okhotsk–Chukchi, Uda–Murgali, and Central Kamchatka volcanogenic belts, shows that the mineralization occurred in two phases. The first phase involved the generation of epithermal Au–Ag mineralization, while the second, plutogenic, phase produced intrusion-related gold system that is seen as epidotization and silicification of rocks in the ore field, as well as in the metamorphism of volcanogenic mineralization. The presence of the later mineralization phase associated with granitoids is typical of the Nevenrekan deposit as distinguished from the other Au–Ag (LS) deposits in the Evensk ore region, and makes it similar in this respect to the Karamken, Nyavlenga, and Cirotan deposits.