Zircon LA-MC-ICP-MS U-Pb dating of the Xianglinpu granites from the Weijia tungsten deposit in southern Hunan Province and its implications for the Late Jurassic tungsten metallogenesis in the westernmost Nanling W-Sn metallogenic belt

The Weijia tungsten deposit, located in the Tongshanling area of western Nanling metallogenic belt, is a newly discovered giant skarn tungsten deposit, with its orebodies mainly occurring at the contact zone between the Xianglinpu granite and Devonian carbonate rock. To determine the timing of the emplacement of the Xianglinpu granite and associated mineralization, the authors collected two kinds of granite, i.e., granite porphyry and quartz porphyry, from the Xianglingpu pluton for zircon LA-MC-ICP-MS U-Pb dating. The results show that the zircon U-Pb ages of granite porphyry and quartz porphyry are (157.8±0.9) Ma (MSWD=1.06) and (158.3±1.4) Ma (MSWD=0.2), respectively, suggesting that their emplacements were coeval within error and they were derived from the same magma source. In addition, the captured zircons from granite porphyry yielded the weighed mean U-Pb age of (435.0±3.1) Ma (MSWD=0.6), which recorded the Caledonian tectonic-magmatic event in this area. Based on the contact relationship between skarn tungsten orebodies and granite, the authors hold that the emplacement of Xianglinpu granite and associated tungsten mineralization occurred at ca.158 Ma, which coincided well with the large-scale mineralization of the Nanling in Middle-Late Jurassic (150-160) Ma. The constraint of the Late Jurassic Weijia skarn-type tungsten deposit implies the great potential of the late Jurassic skarn-type tungsten mineralization in western Nanling W-Sn metallogenic belt.