胶西北东季金矿床钾长石和石英的Ar-Ar年龄及其意义

东季金矿床位于焦家_新城金矿带中 ,其围岩蚀变以钾长石化为特征。作者采用Ar_Ar同位素定年方法对东季金矿床矿脉中的石英及其两侧的蚀变钾长石进行了测试 ,获得钾长石Ar_Ar坪年龄为 (116 .0 7± 0 .30 )Ma ,等时线年龄为 (116 .34± 0 .81)Ma ,石英脉中石英Ar_Ar坪年龄为 (115 .2 2± 0 .2 0 )Ma ,等时线年龄为(114.44± 0 .16 )Ma。这些年龄基本上代表了焦家断裂成矿带的成矿时限。

Ar-Ar Ages of K-feldspar and Quartz from Dongji Gold Deposit,Northwest Jiaodong, and Their Significance

The Dongji gold deposit is located in the Jiaojia-Xincheng gold metallogenetic zone. Its wall alteration is characterized by K-feldspathization. The altered K-feldspar and quartz veins in the Dongji gold deposit were studied with the Ar-Ar isotope dating method. The result shows that the K-feldspar has Ar-Ar plateau age of (116.07±0.30) Ma and Ar-Ar isochron age of (116.34±0.81) Ma and that the quartz penetrating K-feldspar has Ar-Ar plateau age of (115.22±0.20) Ma and Ar-Ar isochron age of (114.44±0.16) Ma. These data represent the ages of the gold mineralization in the Jiaojia metallogenetic zone. Considering other ages obtained in Jiaodong district, it is concluded that the ages of the gold deposits in Jiaobei uplift are almost the same, varying from 114 to 123 Ma. They are also similar to the ages of the gold mineralization in the slide faults in the northern margin of Jiaolai basin.