K-Ar ages of plutonism and mineralization at the shizhuyuan W-Sn-Bi-Mo deposit, Hunan Province, China

The Qianlishan granite complex, situated 16 km southeast of Chenzhou City, Hunan Province, China, hosts the Shizhuyuan W-Sn-Bi-Mo deposit. This complex, which intruded the Protozoic metasedimentary rocks and the Devonian elastic sedimentary and carbonate rocks, consists of mainly medium- to coarse-grained biotite granites and minor amounts of fine-grained biotite granite in addition to granite and quartz porphyry. K-Ar ages suggest three episodes of plutonism: the medium- to coarse-grained biotite granite (before 152 Ma), the fine-grained biotite granite (137 Ma), and the granite porphyry (129-131 Ma). Muscovite ages of the greisen are 145-148 Ma, suggesting that the W-Sn-Bi-Mo mineralization was related to the main, medium- to coarse-grained biotite granites. The K-Ar age of the hydrothermal vein mineralization is 92 Ma and is probably related to the porphyries. (C) 2002 Elsevier Science Ltd. All rights reserved.