【摘要】 本文采用4 0 Ar₃ 9Ar真空击碎技术和阶段加热技术 ,测定了采自落雪矿的“东川式”层状铜矿之两个石英样品的年龄 ,获得了 810～ 770Ma的4 0 Ar₃ 9Ar等时线年龄 ,这是首次获得的“东川式”铜矿的成矿年龄。这些年龄与作者以前获得的脉状铜矿石英的年龄范围一致 ,远远小于赋矿围岩落雪组的年龄。研究结果表明“东川式”层状铜矿并非沉积成因 ,与脉状铜矿一样 ,也是热液成因 ,并且再次证实晋宁_澄江期是东川铜矿的主要成矿期更多还原

【Abstract】 Two quartz samples from the Dongchuan_type layered copper deposits in the Luoxue Mine were dated by 40 Ar 39 Ar crushing and heating techniques. Two age groups of ～1?470 Ma and 810～770 Ma are recognized from the 40 Ar 39 Ar isochron plots. The age of ～1?470 Ma, obtained from the isochron of the quartz 98₄aQ by vacuo crushing technique, is interpreted as the crystallization age of 98₄aQ from the hydrothermal fluid. The ages of 810～770 Ma, obtained from the 40 Ar 39 Ar isochrons of 98₄aQ by stepped heating and of 98₄fQ by crushing and stepped heating, seem quite in agreement with the 40 Ar 39 Ar isochron ages of the quartz samples DC₅0₃Q and DC₅1₁Q by crushing and siliceous breccia DC₅₂ by heating selected from the quartz_vein ores, and are interpreted as the copper mineralization ages. These ore_forming ages further indicate that the major ore_forming process in the Dongchuan copper deposits took place in the Jinning_Chengjiang period.更多还原