【摘要】 鄂东南地区Cu-Au-Mo-（W）矿床是长江中下游地区金属成矿带的重要组成部分。本文利用Re-Os同位素定年方法对该地区5个典型矿床（丰山洞铜钼金银多金属矿床、阮家湾钨铜钼矿床、千家湾铜金矿床、铜绿山铜铁金钼多金属矿床和铜山口铜钼矿床）进行了成矿时代的研究,获得其辉钼矿Re-Os同位素年龄分别为（144.0±2.1）Ma、（143.6±1.7）Ma、（137.7±1.7）Ma、（137.8±1.7）^138.1±1.8Ma和（143.5±1.7）^142.3±1.8Ma,代表各矿床的成矿时代。研究结果表明,鄂东南矿集区内的Cu-Au-Mo-（W）矿床与铜陵、安庆、九瑞矿集区内的矿床几乎是同时形成的,成矿时代可能主要集中于（140±5）Ma,相当于晚侏罗世-早白垩世。在综合已有的岩石学、地球化学和地球物理学资料的基础上,笔者认为,这一成矿事件的深部动力学过程可能是处于中国东部南北向印支期构造域向北东向古太平洋构造域大转折的背景下,与软流圈上涌和玄武质岩浆底侵而导致壳幔同熔有关。更多还原

【Abstract】 Cu-Au-Mo-(W) deposits in southeastern Hubei Province constitute one of the important areas in the Middle-Lower Yangtze River metallogenic belt. Re-Os ages for molybdenite provide constraints on the ore-forming epoch of Late Mesozoic Cu-Au-Mo- (W) mineralization. Molybdenites from the Fengshangdong Cu-Mo-Au-Ag deposit, the Ruanjiawan W-Cu-Mo deposit, the Qianjiawan Cu-Au deposit, the Tonglushan Cu-Fe-Au-Mo deposit and the Tongshanko Cu-Mo deposit yield ages of (144.0±2.1) Ma, (143.6±1.7) Ma, (137.7±1.7) Ma, ( 137.8 ±1.7)～(138.1±1.8) Ma and (143.5±1.7)～(142.3±1.8) Ma, respectively. These data and other highly precise isotopic ages available for Cu-Fe-Au polymetallic deposits in the Middle-Lower Yangtze River metallogenic belt such as molybdenite Re-Os ages and mica ~ 40 Ar-~ 39 Ar ages in the literature demonstrate that Cu-Au-Mo- (W) deposits in Tongling, Anqing, Jiurui and eastern Hubei ore cluster areas were formed at ca.(140±5) Ma, reflecting an important ore-forming episode in this belt. Previous petrological and geophysical data as well as metallogenic ages and their relation to the magmatism and geodynamic framework indicate that largescale Cu-Au-Mo- (W) deposits were developed during the tectonic transformation from the NS-trending compressional regime to NE-trending extension, which resulted from asthenospheric upwelling and basaltic magma underplating in the Late Jurassic-Early Cretaceous period in East China.更多还原