中文摘要:寨上金矿是西秦岭地区近年新发现的大型金矿床。为确定该金矿床的成矿时代,对其含金石英、蚀变绢云母进行了40Ar/39Ar快中子活化法测定。2件样品的40Ar/39Ar坪年龄及等时线年龄分别为(130.62±1.38)Ma、(129.24±1.23)Ma和(125.28±1.26)Ma、(125.56±1.20)Ma,测试结果可信。40Ar/39Ar法年龄测定结果表明,寨上金矿床形成于燕山晚期,并可能历经了约5 Ma时间最终形成。对西秦岭地区已有的金矿床测年数据进行分析后认为,该区可能存在3个金矿成矿高峰期,即220~170 Ma、130 Ma前后和50 Ma左右。
中文关键词:地质学 40Ar/39Ar测年 金矿 寨上 西秦岭
Abstract:The Zhaishang gold deposit, a large_size gold deposit recently discovered in western Qinling area, belongs to the fine_grained dissemination type. Samples of gold_quartz veins and sericite were determined by 40Ar/39Ar fast_neutron activation techniques. The plateau ages of the two samples are (130.62±1.38) Ma and (125.28±1.26) Ma, and the isochron ages are (129.24±1.23) Ma and (125.56±1.20) Ma, respectively. The ages of the samples are reliable. According to the results of the 40Ar/39Ar r dating, the time limit of gold mineralization should be (130.62±1.38) Ma~(125.28±1.26) Ma. Statistics of the time limits of fourteen gold deposits including the Zhaishang deposit in western Qinling show that gold mineralization in this area experienced three important ore_forming events, namely, 220~170 Ma, 130 Ma and 50 Ma. The authors hold that the three events were separately restrained by three different geodynamic environments.
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基金项目:武警黄金指挥部地质专项资金项目(Hj03_01)
引用文本:
路彦明,李汉光,陈勇敢,张国利.2006.西秦岭寨上金矿床中石英和绢云母40Ar/39Ar定年[J].矿床地质,25(5):590~597.2006.dating of alteration minerals from Zhaishang gold deposit in Minxian County, Gansu Province, and its geological significance[J].Mineral Deposits25(5):590~597
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