Abstract:

Yindonggou silver deposit in Hubei Province is a typical giant silver deposit in China. Geological characteristics of this deposit are reported and the ore genesis is proposed in this study. Results of the previous studies and field evidences show that the deposit occurs in metamorphic volcanic rocks of the Wudang Group in Qinling orogen. Orebodies are controlled by shear zones and ores are mainly quartzvein type. The mineral assemblages of wall rock alterations are mainly quartz, ankerite, muscovite, albite, chlorite, pyrite with minor other minerals. Ore fluid has low salinity, low density and bears CO2±CH4±N2. Lower grade Ag+Au ore bodies occur in the upper part and higher grade Ag+Au ore bodies occur in the middle part as well as some small Zn+Pb ore bodies. In the lower part of the deposit, the grade of Ag decreases while the grade of Au increases and many big Zn+Pb ore bodies occur. This mineralization zoning is consistent with the crustal continuum model for orogenictype deposits. These features are similar to those of orogenic gold deposits, which indicate that it is an orogenic silver deposit. The potential Au, Zn, Pb, Cu and Mo resources should be paid much attention.

Key words: Qinling orogen, Hubei Province, Yindonggou deposit, orogenic silver deposit