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兰坪盆地贱金属矿床是一套独特的受逆冲推覆构造系统控制的矿床类型,连城脉状铜矿床是其重要组成之一。以往研究采用多种测年手段限定脉状铜矿成矿年龄,但结果分歧较大。本文采用辉钼矿Re-Os同位素定年方法,获得连城矿床辉钼矿的Re-Os同位素模式年龄为(48.14±0.87)Ma,等时线年龄为(49.0±1.3)Ma,初步厘定兰坪盆地热液脉型铜矿床形成于48～49Ma。结合区域地质与控矿构造分析,该矿床应为盆地西部逆冲带逆冲变形过程中的产物,由此限定兰坪盆地西部逆冲推覆的起始时间至少早于49Ma,同时佐证了兰坪盆地西部逆冲带内以Cu(-Ag)为主的成矿系统的形成发育可能早于东部逆冲推覆带内以Pb-Zn为主的成矿系统。
The base metal deposit in Lanping Basin is a unique type of deposit under the control of a thrust-nappe structure system. The Liancheng vein copper deposit is one of its important components. In the past, a variety of dating methods were used to limit the metallogenic age of vein-shaped copper deposits, but the results were quite different. In this paper, Re-Os isotopic dating of molybdenite was used to obtain the Re-Os isotopic pattern age of (48.14 ± 0.87) Ma and the isochron age of (49.0 ± 1.3) Ma for the molybdenite in Liancheng deposit. Hydrothermal pulse copper deposits formed in 48 ~ 49Ma. Based on the analysis of regional geology and ore-controlling structure, this deposit should be the product of thrust deformation in the western thrust belt of western basin, thus defining the start time of thrust nappe in the western part of Lanping Basin as early as at least 49Ma, The formation and development of the Cu (-Ag) -based metallogenic system in the western thrust belt of the Ping basin may be earlier than the Pb-Zn-dominated metallogenic system in the eastern thrust belt.