Regularities of Ore-Controlling Structures and Exploration Predictions of Buzhu Au (Sb) Deposit in Kangma County, South Tibet, China

The Au-Sb-Pb-Zn-Ag Polymetallogenic Metallogenic belt in South Tibet, also known as the North Himalayan Metallogenic belt, is an important part of the Tethyan Himalayan Metallogenic Region. Although Kangma area is in an advantageous metallogenic location where the SN-trending faults cross the EW- trending faults, few breakthroughs have been made in exploration prediction for a long time due to the lack of clear ore-controlling regularities, feasible prospection methods, and effective prediction examples for reference, which caused by high altitude and thick coverage. In recent years, the discovery of a group of deposits such as Buzhu gold (antimony) deposit has filled the gap of exploration in this area. However, due to the lack of in-depth understanding of the internal architecture and ore-controlling styles of the fault zones, the exploration of Buzhu deposit is seriously restricted. Based on detailed geological survey, the internal architectures of NW- (and EW-) and SN- trending fault zones in this deposit have been systematically dissected here. It is identified that both sets of fault zones were composed of the fault core in the central part and the damage zone in the peripheral. In the NW- (and EW-) trending fault zones, the crumpled pyrite-bearing quartz veins were controlled by the fault core and the straight and steep quartz veins bearing multiple sulfide phases and quartz veins bearing abundant arsenopyrite filled in the joints of the damage zone. In the SN-trending fault zones, the fault core consisting of cleavage zone and breccia zone is barren. While, the bedding tension fractures in the damage zone were filled by high grade veins characterized by obvious limonite and clay alteration. Combined with regional tectonic evolution, a three-stage evolution model depicting the formation, development and ore-controlling of the major fault zones in Buzhu deposit is established in this paper. Under the guidance of this model, 6 prospecting targets were delineated according to the geological facts combined with the prospecting information such as synthetic anomalies of 1:10 000 soil geochemical exploration, wall rock alteration and ore outcrops. And each of the 2 targets was finally selected in the 3 levels of A, B and C, comprehensively considering various factors. Through the above studies on the internal architecture, ore-controlling regularities and evolution model of the fault zones, as well as the delineation of the targets combined with synthetic anomalies, the authors hope to provide useful reference for the ore genesis research and prospection in the Buzhu deposit and Kangma areas.