GEOLOGICAL CHARACTERISTICS OF DASHANKOU GOLD DEPOSIT IN HEJING COUNTY OF XINJIANG: CONTRAST WITH MURUNTAU GOLD DEPOSIT

Dashankou gold orebodies are situated in Upper Silurian-Lower Devonian carbon-containing fine-grained clastic rocks of Dashankoufm.The ore-control structure is Dashankou ductile shear zone.The general structure in the mine trends NWW.The main tectonic framework is Wulansaier-Dashankou ductile shear zone which is confined by Dashankou and Aikendaban faults.The ductile shear zone is 2~3 km wide and more than 100 km long. In the ore district the outcropping length of the ductile shear zone is 1.7 km and the width of strong shear mylonite zone is 300~500 m. The ductile shear zone shows as an intense schistosity zone.The S-C febrics, b-type folds and structural lenticules are commonly seen, and the quartz-veinlet appear in ptygmatic folds.The ductile shear zone consists of mylonite and mylonitized rocks.Dashankou gold deposit, whose ore is composed of quartzvein, stockwork quartz veinlet and alteration mylonite, is located in the ductile shear zone.The gold orebodies all occur in the mylonite and mylonitized rocks.There are no bigger intrusive rock mass.Some veins of diorite and dacite intrude into the ductile shear zone.This paper studies Dashankou gold deposit by contrasting it with Muruntau gold deposit on ore-bearing formation, ore-control structure, magmatism, orebody characteristics, constitution of mineral and element, scale of gold deposit and mineralized area, and also referring to the newest data of ultradeep drill of Muruntau gold deposit.The conclusion is that the two gold deposits belong to the same type although they have some differences.The authors also emphasize that more attention should be paid to the exploring and researching on deep mineralization besides on regional mineralization condition, in order to resolve the problem that "there are plenty of smaller gold orebodies but not bigger ones in Dashankou goldfield".