赣南九龙脑矿田东南部不同类型钨矿的辉钼矿Re-Os年龄及地质意义

Molybdenite Re-Os Isotopic Dating on Different Types of Tungsten Deposits in Southeast of Jiulongnao Orefield and Its Geological Significances

通过对赣南九龙脑矿田东南部洪水寨云英岩型钨矿、九龙脑内带石英脉型钨矿和樟东坑外带石英脉型钨矿等3个不同类型钨矿的辉钼矿Re-Os同位素测年，结果显示其成矿年龄集中在150～160Ma之间，属于华南中生代第二次大规模成矿作用的产物。3个矿床的成矿年龄分别为（156．3±1.3）Ma（MSWD=1，5）、（151．5±1．1）Ma（MSWD：1．12）和（151．3±1．7）Ma（MSWD=0．35），与九龙脑岩体SHRIMP锆石U—Pb年龄（155．8±1．2Ma）存在最小4Ma的时差。成矿年龄由岩体内部向外接触带呈现变年轻的趋势，反映了3个矿床为同一岩浆-流体体系作用的产物，成矿流体以九龙脑岩体为中心向外逃逸，并呈现脉动式成矿的特点。

The molybdenite Re-Os isotopic dating on three tungsten deposits shows us that the ages of amerem types of W-Sn metallogenesis in Jiulongnao orefield are mainly concentrated in the range of 150 to 160 Ma, which is correspondent to the time of the second large-scaled regional mineralization in the Mesozoic. The mineralization ages of three deposits are （156.3 ± 1.3） Ma （MSWD = 1.5）, （151.5 ± 1.1） Ma （MSWD = 1.12） and （151.3± 1.7） Ma （MSWD = 0.35）, respectively. There are 4 Ma time gap between Jiulongnao granite emplacement and W-Sn metallogenesis at least. The rock-forming and ore-forming ages are demonstrated by young trend from Jiulongnao granite, through endocontact to exocontact, which indicate that these three deposits are the products of the same magma-fluid system. Ore-forming fluids which escape from Jiulongnao granite can form different types of deposits, and show the characteristics of pulse-type mineralization.