Molybdenite Re-Os, zircon U-Pb dating and Hf isotopic analysis of the Shuangqing Fe-Pb-Zn-Cu skarn deposit, East Kunlun Mountains, Qinghai Province, China

摘要

The Shuangqing Fe-Pb-Zn-Cu deposit is located in the Xiangride County of Qinghai Province, China, and is a typical example of skam deposits in the East Kunlun Mountains. Skamization and mineralization took place along the contact zone between Carboniferous carbonates and the concealed Triassic plagiogranite. LA-ICP-MS U-Pb dating of zircons from the plagiogranite has yielded ages of 227.2 +/- 1.0 and 226.54 +/- 0.97 Ma, which are interpreted as the emplacement age of the plagiogranite. Molybdenites separated from ore-bearing quartzveins yielded a Re-Os isochron age of 226.5 +/- 5.1 Ma. These age data confirm that both intrusion and related skarn mineralization initiated at similar to 227 Ma. Re contents of molybdenite, zircon epsilon(Hf)(t) and Hf-176/Hf-177 values fall into the ranges 3.31 to 6.58 mu g/g, -8.6 to -0.0, and 0.282403 to 0.28263850, respectively. The timing of the Shuangqing Fe-Pb-Zn-Cu mineralization coincided with a major change in the stress field in East Kunlun from transpression to extension, related to the partial melting of thickening crustal materials in a post-collisional tectonic setting. (C) 2014 Elsevier B.V. All rights reserved.