Tectonic framework of late Paleozoic and the correspondent poly-metallic mineralization in the northern Xinjiang western Tianshan Mts., NW China

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Zhang, Zuoheng۱; Wang, Zhiliang۱; Zuo, Guochao۲; Liu, Min۱
Holding Date 08 September 2008

The Xinjiang Western Tianshan composite orogenic belt is located between the Yilianhabierga thrust fault in the north and Heiyingshan-Huolashan thrust fault in the south. Recently research achievement on Paleozoic tectonic geodynamic evolution in the western Tianshan Mountains show that the research area have experienced long tectonic evolution history from Paleo-Proterozoic to Cenozoic, i.e., accretion and break-up of Pangea in Palaeoproterozoic and Mid-proterozoic, generation and break-up of Rodinia supercontinent in Neoproterozoic, generation and closure of Palaeo-Asian Ocean in Palaeozoic, and intraplate tectonic evolution in Mesozoic-Cenozoic. The late Palaeozoic is the most important stage for the mineralization of poly-metallic copper-gold deposits. As the result of the subduction of Junggar ocean crust to central Tianshan plate during late Palaeozoic, the northern part of Xinjiang Western Tianshan orogenic belt exist three major E-W-trending tectonic units, i.e., Alatao-Keguqin island arc, Boluokeluo back-arc basin and Awulale rift zone.
Based on ore-bearing host rocks and mineralization patterns of copper-gold deposits in the northern part of Xinjiang western Tianshan Mountains, copper deposits in this belt can be classified into three types, i.e. porphyry copper deposits, skarn-copper deposits and volcanogene hydrothermal copper deposits; gold deposits can be grouped into two types, i.e. epithermal gold deposits and porphyry gold deposits. The distribution of the metallic mineralizaition zones is almost correspondent with the three E-W-trending mineralization belts. There developed the Alatao-Keguqin copper polymetallic mineralization zone, Boluokeluo gold polymetallic mineralization zone and Awulale copper-silver poly-metallic mineralization. The Alatao-Keguqin zone comprises porphyry-skarn copper deposits related to the Mid-Proterozoic limestone and Mid-Hercynian hypabyssal mid-acid intrusive rocks (i.e., Lamasu copper deposit), porphyry copper deposits connected with Mid-Hercynian hypabyssal acid intrusive rocks (represented by Dabate copper deposit). Boluokeluo gold poly-metallic mineralization zone consists of epithermal gold deposits related to Lower Carboniferous mid-acid pyroclastic rock and mid-basic lava(i.e., the Axi large scale gold deposit) and porphyry gold deposits connected with Mid-Hercynian hypabyssal mid-acid intrusive rocks(only the Tawuerbieke small scale gold deposit has been discovered in this area). Awulale copper-silver poly-metallic mineralization zone is composed of volcanogene hydrothermal copper deposits related to Permian continental mid-basic volcanic rock (i.e., the Qiongbulake small scale deposit), porphyry copper deposits connected with Late-Hercynian hypabyssal mid-acid intrusive rocks (i.e., the Qunji small scale deposit).
Acknowledgements
This work was supported by State 305 Project (N°. 2006BAB07B08-01) and Geological Survey Project (N°. 1212010561603-3).