浙江省桐村钼矿床Re-Os同位素年龄及地质意义

浙江桐村斑岩型钼矿床位于钦杭成矿带东段,紧邻赣东北成矿带,矿床的形成与燕山早期侵入的同熔型花岗岩有关,含矿岩体的成岩年龄165 ～168Ma.辉钼矿矿石呈浸染状产于岩体内部或岩体与围岩的接触带.本文首次对矿床中3件辉钼矿样品进行了Re-Os同位素年代学研究,测得辉钼矿的等时线年龄为162.2Ma±1.3 (MSWD =0.006),代表了成矿年龄.成矿成岩年龄具有一致性,矿床成因类型为斑岩-矽卡岩型钼(铜)矿床.

Re-Os Dating of Molybdenite from the Tongcun Porphyry molybdenum Deposit in Western Zhejiang Province and Its Geological Implications

Abstract: The Tongcun porphyry molybdenum deposit is located in the east section of the Qinzhou-Hangzhou metallogenic belt, close to the large-scale mineralized concentration area in northeastern Jiangxi Province. The formation of the deposit is related to the syntecticgranite which invaded in the early Yanshan period. The mineralization age of the granite is 165-168Ma. The disseminated molybdenite occurs in the contact zone between the intrusion and alteration zone. Re-Os isotopic age of the three molybdenite samples was measured for the first time, yielding 187Re-187Os isochron age of molybdenite as 161.8±2.2Ma(MSWD=0.006), representing the mineralization age. The ore-forming age is concordant with the rock-forming age, and the deposit is of porphyry-skarn-type molybdenum ore deposits.