安徽铜陵地区幔源岩浆底侵作用的时代——朝山辉石闪长岩锆石SHRIMP定年

SHRIMP U-Pb Geochronology of Pyroxene Diorite in the Chaoshan Gold Deposit and Its Geological Significance

铜陵是中国著名的铜 (金 )、铁成矿带 ,其金属矿产与区内燕山期侵入岩有着密切的时空、成因联系。对与铜陵地区典型的夕卡岩型朝山金矿有关的辉石闪长岩中的锆石进行了SHRIMP精确定年研究 ,辉石闪长岩锆石2 0 6Pb/2 3 8U年龄为14 2 .9± 1.1Ma ,结合新获得的新桥矶头石英闪长岩和铜官山石英闪长岩的锆石U Pb年龄。认为铜陵地区幔源岩浆底侵作用发生在早白垩世 (133± 14 3Ma) ,这一时期也是成矿的重要时期。

Sensitive High Resolution Ion Microprobe (SHRIMP) U-Pb zircon dating of pyroxene diorite from the Chaoshan gold deposit in Tonglin mineral district of Anhui Province indicates intrusive activity at 142.9±1.1 Ma. New U-Pb ages were obtained for quartz diorite from Tongguanshan quartz diorite and the Xinqiao Cu-S-Fe-Au deposit. These data indicate that mantle source magma-tic underplating occurred in Early Cretaceous (133～143 Ma). This suggests that magma-tism and associated ore-forming process became active in this area since the Yanshanian movement.