摘要
赣中变质岩带主要由斜长(云母)变粒岩、十字石榴云母片岩、云母石英片岩夹斜长角闪岩组成。斜长角闪岩Sm-Nd全岩等时线年龄为1113±19Ma,相当于该变质岩带的原岩形成年龄。ε_(Nd)(t)值为2.4±0.1,说明岩浆起源于亏损程度较低的地幔源区:726.6±1.1Ma、403.1±6.4Ma的Rb-Sr等时线年龄表明赣中地区在新元古代末期、加里东期经历了一次强烈的构造变质热作用,其地质、地球化学特征及时代可与浙闽地区陈蔡群、建瓯群进行对比。因此赣中变质岩带并非长期公认的华南加里东褶皱带,应是华夏地块的一部分,这一事实对华南大地构造单元的划分及构造演化具有重要意义。
The central Jiangxi metamorphic belt consists of plagioclase (mica) granulitite (leptynite) , staurolite-garnet-mica schist and mica-quartz schist with amphibolite. The whole-rock Sm-Nd isochron age of amphibolite is 1113±49 Ma, corresponding to the formation age of the pro-toliths. εNd = 2. 4±0. 1 . which indicates that their parental magma was derived from a slightly depleted mantle source. The Rb-Sr isochron ages of 726. 6±1.1 and 403. 1±6. 4 Ma show that the central Jiangxi area went through one intense tectono-metamorphic thermal event in the terminal Neoproterozoic and the Caledonian stage. Its age and geological and geochemical characteristics can be completely correlated with the Chencai Group in Zhejiang Province and the Jian'ou Group in Fujian Province. Therefore, the central Jiangxi metamorphic belt belongs to the Cathaysian massif rather than the Caledonian fold belt of South China. This view has important significance for tectonic evolution and division of South China.
出处
《地质论评》
CAS
CSCD
北大核心
1999年第2期129-134,共6页
Geological Review
基金
核工业核能资源开放实验室研究基金
国家教委博士点研究基金(编号9528418)
关键词
变质岩
钐-钕
铷-锶
同位素年代
amphibolite
migmatite and felsic vein
Sm-Nd isotopes
Rb-Sr isotopes
Neo-proterozoic metamorphic rocks
central Jiangxi metamorphic belt
