Abstract:

Guanshan Cu-Pb-Au deposit in Lishui basin of Jiangsu Province is a high sulphidation type epithermal deposit hosted in Late Mesozoic subvolcanic rocks. 40Ar/39Ar dating was performed on two sericite samples collected from sericitized subvolcanic wallrocks of Guanshan deposit. The results yield plateau ages of（120.8±1.0）Ma and（116.0±1.3）Ma，respectively, suggesting that the major mineralization of Guanshan belongs to the large-scale Mesozoic metallogenic event occurred in eastern China. During 125 Ma to 115 Ma, most part of eastern China was affected by extensional tectonic stress, resulting in large-scale magmatism and formed a series of fault-depressed basins, including the Lishui volcanic basin. In this basin, upwelling of deep-seated magma provided magmatic heat, triggered circulation of meteoric water, which mixed with magmatic fluid, and finally deposited the ore minerals in brittle fractures in the trachyte-porphyry wallrocks.

Key words: 40Ar/39Ar dating, high sulphidation type epithermal deposit, Guanshan Cu-Pb-Au deposit, large-scale Mesozoic metallogeny in eastern China