伊春火成岩带二股矽卡岩型铁多金属矿床^(40)Ar_^(39)Ar年代学及其地质意义

^(40)Ar_^(39)Ar dating of Ergu Fe_polymetalic skarn deposit in Yichun igneous belt and its geological implications

文章在矿床地质特征研究基础上,首次确定了伊春火成岩带内的二股铁多金属矿床的成矿时代。结合前人研究成果,分析了伊春火成岩带早中生代金属矿床的成矿时限,成矿规律及找矿方向。金云母40Ar_39Ar同位素测年结果表明,二股铁多金属矿床的成矿年龄为(181.0±4.2)Ma。伊春火成岩带内早中生代金属成矿作用分为:早期(200~181 Ma)与二长花岗岩有关的矽卡岩型_热液脉型铁多金属矿床成矿作用;晚期(178~175 Ma)与花岗斑岩有关的斑岩型钼矿床成矿作用。晚三叠世—早侏罗世花岗岩类侵入岩(如二长花岗岩)与铅山组碳酸盐岩接触部位是伊春火成岩带内矽卡岩型_热液脉型铁多金属矿床成矿的有利部位。

In this study,（40）Ar_（39）Ar dating of the Ergu Fe_polymetalic skarn deposit was conducted, and the time, metallogenic regularity, and prospecting direction of the Mesozoic mineralization in Yichun igneous belt were studied.The results show that phlogopite from the Ergu deposit yielded an（40）Ar_（39）Ar isochron age of（ 181. 0 ± 4. 2） Ma. The Mesozoic mineralization in Yichun igneous belt can be divided into two episodes, i. e., the 200～181 Ma skarn_vein Fe_polymetallic mineralization related to monzonitic granite and the 178～175 Ma porphyry Mo mineralization associated with granite porphyry. It is held that the contact zone between the Late Triassic_Early Jurassic granitoids and the carbonate rocks of Qianshan Formation is favorable for skarn_vein Fe_polymetallic mineralization.