文章研究了甲玛矿区内中酸性侵入岩的侵位时序及岩浆-成矿作用.以实测地质资料为基础,结合中酸性侵入岩的LA-ICP-MS锆石U-Pb定年,初步厘定了甲玛矿区内中酸性岩浆岩的侵位时序,从早至晚依次为:花岗斑岩(15.31～16.27 Ma)-石英闪长玢岩-二长花岗斑岩(14.81 Ma)-花岗闪长斑岩.以辉钼矿为例,甲玛矿床显示有3期成矿作用,各期成矿过程分别对应于花岗斑岩或石英闪长玢岩、二长花岗斑岩和花岗闪长斑岩3期不同强度的岩浆作用过程.甲玛矿床的形成是3期岩浆-成矿作用叠加的结果.%This paper deals with the emplacemem timing of the intermediate-acidic intrusive rocks in Jiama of Tibetand its metallogenic significance. Based on the measured geological data and LA-ICP-MS U-Pb zircon ages of the four intermediate-acidic intrusive rocks, the authors preliminarily regularized the timing sequence, which is from early to late in order of porphyry granite (15.31 Ma～16.27 Ma)-quartz diorite porphyrite-adamellite porphyry (14.81 Ma)- granodiorite-porphyry; Exemplified by molybdenum, the Jiama ore deposit assumes three periods of metallogenesis, i.e., the ore-forming processes corresponding respectively to different degrees of magrnatic activities of porphyry granite or quartz diorite porphyrite, adamellite porphyry and granodiorite-porphyry. The Jiama ore deposit resulted from the superposition of the three periods of magma-mineralization.
展开▼
