Geochemistry and U-Pb geochronology of tungsten deposit of Huaniushan island arc in the Beishan Orogenic Belt, and its geodynamic background

The newly-discovered tungsten deposits are located in the Beishan Orogenic Belt, NW-China, Central Asian Orogenic Belt. There are three mineralized granitoid intrusives of them; the Pantuoshan, Yingzuihongshan and Yushan. By high-precision SIMS zircon U-Pb dating, we obtained the concordant age of 422.0 +/- 1. 5Ma and 417.0 +/- 1. 7Ma for monzogranite and K-feldspar granite of Pantuoshan ore-bearing intrusion, and K-feldspar granite of Yingzuihongshan emplaced at age of 424.0 +/- 1. 3Ma. In addition, we have got the age of 280. 8 +/- 3. 0Ma of Yushan granite. The geochemical data shows that the three intrusions characterized by high REE and LREE-rich pattern, enriched LILE (Th, Zr, Hf) and HFSE (U, Pb), depleted HFSE (Ta, Nb, Ti, P). In combination with the evolution of the Paleozoic Beishan Orogenic Belt, we suggest that the Guoqing and Yingzuihongshan tungsten deposits occurred by the collision between Gongpoquan and Huaniushan island arc, and Yushan tungsten deposit formed in the Late Paleozoic back-arc extension tectonic setting.