Oceanic Subduction-continental Collision Transition and Epithermal Gold Mineralization: Insight From Geochronological Study of the Tawuerbieke Deposit, Tulasu Ore Cluster, Western Tianshan

Epithermal gold deposits form from hydrothermal systems at shallow depth and low temperature, and commonly develop in compressional setting at active volcanic arcs or extensional environment at back-arc basins both in oceanic subduction geodynamic setting, e.g., the circle Pacific region (Simmons et al., 2005). In addition, epithermal Au ± Ag deposits in the Alpine-Himalayan belt appeared to be formed during continental collision (e.g., Chah Zard in central Iran; Duolong in Tibet of SW China). Currently, there is no consensus on the tectonic setting of epithermal Au deposits in the Central Asian Orogenic Belt (CAOB), possibly due to the multiple subduction–collision and amalgamation processes of the Paleo-Asian ocean during Neoproterozoic to Paleozoic. The western Tianshan of the Southwestern CAOB, represents an important porphyry Cu ± Au ± Mo and epithermal Au belt that extends for more than 2500 km from Uzbekistan to NW China. The Tulasu area, is known to be an important epithermal gold ore cluster in north Chinese western Tianshan, and hosts several important epithermal Au deposits or prospects, e.g. Axi, Jingxi–Yelmend, Tawurbieke, and Qiabukanzhuota. In this study, based on a systematic field investigation, we carried out zircon SHRIMP U–Pb studies on magmatic rocks in the Tulasu area, together with new Re–Os pyrite age of the Tawuerbieke gold deposit, in an attempt to detect the geodynamic setting of epithermal gold system in the CAOB.