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内蒙古阿拉善地区朱拉扎嘎金矿是新近发现的特大型层控改造型金矿床,该矿床以产于中元古界地层中和巨大的找矿潜力而引人注目。容矿岩石主要为钙质粉砂岩、粉砂质板岩。曾采用颗粒锆石U-Pb法和~(40)Ar/~(39)Ar法对成矿期花岗斑岩、成矿后期闪长玢岩和含金石英-硫化物矿体进行了年龄测定,获得成矿期花岗斑岩锆石U-Pb年龄为(304±5)Ma,成矿后期闪长玢岩为(258.6±5.7)Ma,金矿体中石英的~(40)Ar/~(39)Ar年龄为(282.3±0.9)Ma。现采用SHRIMP锆石U-Pb法对成矿期花岗斑岩和成矿后期闪长玢岩进行了重新测年,结果表明花岗斑岩的形成时代为(280±6)Ma,闪长玢岩的形成时代为(279.7±5.2)Ma,两者的年龄差仅0.3 Ma,从而限定了朱拉扎嘎金矿的形成年龄,非常接近于280 Ma(279.7～280 Ma)。
The Zhulazaga gold deposit in the Alashan region of Inner Mongolia is a newly discovered super-large stratified controlled-alteration gold deposit that has attracted the attention of the Middle Proterozoic strata and its huge prospecting potential. The ore-bearing rocks are mainly calcareous siltstone and silty slate. The granitic porphyry during the ore-forming period, diorite porphyrite and gold-bearing quartz-sulfide ore bodies have been studied by U-Pb method and ~ (40) Ar / ~ (39) Ar method The zircon U-Pb age of the granite porphyry was (304 ± 5) Ma during the metallogenic stage and (258.6 ± 5.7) Ma for the later metallogenic stage. The ~ (40) Ar / ~ (39) Ar age was (282.3 ± 0.9) Ma. The SHRIMP zircon U-Pb method is used to re-measure granite porphyry in the ore-forming period and diorite porphyrite in the late stage of ore-forming. The results show that the formation age of granite porphyry is (280 ± 6) Ma, The age of formation of pluton is (279.7 ± 5.2) Ma, with an age difference of only 0.3 Ma, which limits the age of Jura-Zhaga gold deposit to 280 Ma (279.7-280 Ma).