中条山地区前寒武纪地层同位素年龄及其意义  

ISOTOPIC AGES OF PRECAMBRIAN STRATA IN THE ZHONGTIAO MOUNTAINS AREA AND THEIR SIGNIFICANCE

作　　者：孙海田[1] 葛朝华[1] 冀树楷 

机构地区：[1]中国地质科学院矿床所 [2]山西省地矿局地研所

出　　处：《中国区域地质》1990年第3期237-248,共12页Regional Geology of China

摘　　要：中条山地区位于华北地台南部,涑水群杂岩构成本区结晶基底,其上为绛县群,中条群、西洋河群等前寒武纪地层。绛县群变超钾质火山岩系,全岩Sm-Nd等时线同位素年龄为2.63±0.10(Zσ)Ga;铜矿峪铜矿容矿钙碱性变火山一次火山岩系,原生锆石U-Pb等时线同位素年龄为2.182±0.015Ga;铜矿峪铜矿容矿钙碱性变火山一次火山岩系和胡一篦型层控铜矿床容矿热液沉积岩系,全岩Rb-Sr等时线同位素年龄分别为1.778±0.027Ga和1.832±0.026Ga。前两者代表超钾质火山岩系及钙碱性火山一次火山岩系形成时代,后者反映区域变质作用时代。根据前人Rb-Sr等时线同位素年龄研究资料,西洋河群安山岩系形成于1.454±0.05Ga。The Zhongtiao Mountains area is located in the southern part of the North China platform. The Sushui Group complex constitutes the crystalline basement of the area, which is overlain by the Precambrian Jiangxian, Zhongtiao and Xiyanghe Groups. The whole-rock Sm-Nd isochron age of the ultrapotassic metavolcanic series of the Jiangxian Group is 2.63±0.10 (2σ) Ga; the zircon U-Pb isochron age of the host calc-alkali metavolcanic-subvolcanic series of the Tongkuangyu copper deposit and the host hydrothermal-sedimentary series of the Hu-Bi-type stratabound copper deposit are 1.778±0.027 Ga and 1.832±0.026 Ga respectively. The former represent the formation ages of the ultrapotassic volcanic series and calc-alkali volcanic-subvoleanic series, while the latter represent the age of regional metamorphism. By means of the data of the Rb-Sr isochron ages obtained by predecessors, the andesite series of the Xiyanghe Group has been determined to be formed 1.454±0.05 Ga ago.

关 键 词：前寒武纪 同位素 年龄 

分 类 号：P534.41[天文地球—古生物学与地层学]