Geological Features and Genesis of Beijinshan Gold Deposit,Gansu Province

Located in the Wen county-Kang county metallogenic belt,Beijinshan gold deposit is one of the Yangshan belt's seven ore blocks.Recently,three fracture zones were found in the gold deposit alteration what were produced in the altered phyllite of Sanhekou group the second lithologic in the Devonian system.The fracture structure is the main ore-controlling factor for Beijinshan gold deposit.Although there is no magmatic rock's exposing,the hydrothermal made by the fracture structure's sliding and the hot brine produced by the magmatic activity of the adjacent Yangshan large gold deposit increase the solubility of gold.It made gold and other elements activated so that they moved to be the mineralization in the suitable tectonic position.This deposit is pyritization,silification,sericitization,carbonation and some other medium/low temperature hydrothermal alteration assemblage.It seems that this deposit is a hydrothermal broken altered rock gold deposit.