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探讨江西省乐平市塔前钼(钨)矿床成矿岩体的形成时代。通过对塔前钼(钨)矿床进行野外地质调查和SIMS锆石U-Pb测龄,结果表明其成矿母岩为花岗闪长斑岩,其加权平均年龄为160.9±2.5 Ma(MSWD=0.69),代表矿区花岗闪长斑岩的结晶时间。这与矿区矽卡岩矿石中辉钼矿Re-Os同位素年龄(162±2 Ma)在误差范围内一致,说明此矿床形成于中侏罗世晚期。将其与钦杭成矿带东段塔前-赋春成矿带与乐华—德兴成矿带中同类矿床进行对比发现,前者成矿年龄集中于161 Ma±,控岩控矿构造皆以北东向为主;而后者成矿年龄集中于170 Ma±,控岩控矿构造以北西向为主,预示钦杭成矿带东段2个成矿阶段(170~161 Ma B.P.)区域构造应力方向可能发生了重大转变。
To discuss the formation age of the ore-forming rock mass of the Tazen molybdenum (tungsten) deposit in Leping City, Jiangxi Province. Field geological survey and U-Pb dating of SIMS zircons of the former molybdenum (tungsten) deposit indicate that the metallogenic parent rocks are granodiorite porphyry with a weighted average age of 160.9 ± 2.5 Ma (MSWD = 0.69), representing the crystallization time of the granodiorite porphyry in the ore district. This is in agreement with the Re-Os isotopic age of molybdenite (162 ± 2 Ma) in the skarn ore area, indicating that this deposit was formed in the late Middle Jurassic. Compared with the similar deposits in the Tazian-Fuchun metallogenic belt and the Leroy-Dexing metallogenic belt in the eastern segment of the Qinhang metallogenic belt, the former metallogenic age was concentrated at 161 Ma ±, and the controlled ore-controlling structures Mainly in the north and east direction. The latter metallogenic age is concentrated at 170 Ma ±. The controlled ore-controlling structure is dominated by the NW direction, which indicates the two mineralization stages (170 ~ 161 Ma BP) in the eastern part of Qinhang metallogenic belt There may be a major shift in the direction of tectonic stress.