【摘要】 为了解赣中周潭群的构造属性和华夏陆块的演化历史,本文对崇仁地区的斜长角闪岩开展了锆石U-Pb年代学和地球化学研究。结果表明,崇仁地区斜长角闪岩形成年龄为（870±9） Ma,其SiO₂含量为51. 22%～53. 11%,MgO为6. 16%～6. 74%,TiO₂为1. 23%～1. 40%,原岩为拉斑玄武岩。崇仁地区斜长角闪岩LaN/YbN值为1. 85～2. 12,GdN/YbN值为1. 10～1. 17,与E-MORB相比富集大离子亲石元素。样品亏损高场强元素,具有明显的Nb-Ta异常、Nb/La=0. 50～0. 72。样品的εNd（t）值为5. 1～6. 0,其源区为受俯冲组分改造的地幔楔,其构造背景为弧后盆地。结合前人在华夏陆块的工作,推测崇仁相山新元古代～870 Ma斜长角闪岩与北侧的弋阳周潭群火山岩指示了华夏内部新元古代弧后盆地的存在。更多还原

【Abstract】 In order to understand the tectonic setting of the Zhoutan Group and the Neoproterozoic evolution history of the Cathaysia Block,we have carried out a study on the zircon U-Pb geochronology and whole-rock elemental and Sr-Nd isotopical geochemistry of the Chongren amphibolites in this paper. The results show that the representative sample of the Chongren amphibolites has a zircon U-Pb age of（870±9） Ma. These amphibolites have SiO₂ contents ranging from 51. 22% to53. 11%,MgO contents varying from 6. 16% to 6. 74% and TiO₂ contents varying from 1. 23% to 1. 40%,respectively.Their protolith could be tholeiite. They have relative flat REE-normalized pattern with LaN/YbNvalues varying from 1. 85 to 2. 12 and GdN/YbNvalues varying from 1. 10 to 1. 17. They are relatively enriched in large ion lithophile elements and depleted high field strength elements with obvious Nb-Ta anomalies and Nb/Ta values of 0. 50-0. 72 comparing to those of the E-MORB. In addition,they have εNd（t） values ranging from 5. 1 to 6. 0,suggesting that they could be derived from the metasomatized mantle wedge by subduction components and formed in a tectonic setting of back-arc basin.Based on our data and other available data of the Neoproterozoic（～ 870 Ma） Chongren amphibolites and volcanic rocks of the Zhoutan Group in the Yiyang area,it is proposed that there could be a Neoproterozoic back-arc basin in the Yiyang-Chongren area within the Cathaysia Block.更多还原