黄沙坪铅锌多金属矿成岩成矿年龄测定及地质意义

Petrogenetic and Metallogenic Age Determination of the Huangshaping Lead-Zinc Polymetallic Deposit and its Geological Significance

黄沙坪铅锌多金属矿位于南岭多金属成矿带湘南矿集区。自危机矿山接替资源勘查项目执行以来,又探明资源量达大型的含铁钨锡多金属矿及达中型的铜多金属矿,为开展科学研究提供了丰富的资料。笔者在前人研究的基础上,通过采用锆石SHRIMP U-Pb和辉钼矿Re-Os等时线定年方法,对分别对矿区56m中段的石英斑岩体以及矿石中共生的辉钼矿进行了精确定年,获得石英斑岩体锆石SHRIMP U-Pb年龄为152±3Ma,三组同一中段不同位置的辉钼矿Re-Os等时线年龄为159.4±3.3Ma,157.5±2.4Ma和157.6±2.3Ma。测定结果为厘定黄沙坪铅锌多金属矿成岩成矿作用多期多阶段性特点提供了重要的依据。

The Huangshaping lead-zinc ore deposit is located in the South Hunan ore concentration area of the Nanling polymetallic metallogenic belt. Since the implementation of the project for exploration of replacement resources in crisis mines, two ore deposits have been found： one is a Fe-W-Sn polymetallic deposit whose metal reserves have reached the large-sized ore deposit, and the other is a Cu polymetallic deposit whose metal reserves have attained medium size. These achievements provide abundant information for the study of ore deposits. Based on data available, the authors carried out a study of the zircon U-Pb age of the granite porphyry and the molybdenum mineralization age. It is shown that the quartz porphyry zircon U-Pb weighted isochron age is 152.3±3 Ma, and the molybdenite Re-Os isochrone ages are 159.4±3.3 Ma, 157.5±2.4 Ma and 157.6±2.3 Ma （dated at different positions of the same 56 m elevation）. These data provide important evidence for collating and stipulating the multi-period and multi-phase rock-forming and ore-forming characteristics of the Huangshaping lead-zinc deposit.