摘要
锡林浩特市西南白音塔拉地区锡林郭勒杂岩出露在华北板块北缘古生代褶皱带中的强烈变形变质地层中,主要由石英片岩、黑云母石英片岩夹斜长角闪岩组成。Sm-Nd全岩等时线年龄为1286±26Ma,应相当于锡林郭勒杂岩的原岩形成年龄。ε_(Nd)(t)值为8.5±0.6,说明岩浆来源于亏损地幔源区。Rb-Sr全岩等时线年龄为659.9±29.3Ma,被解释为主期变质变形年龄。该年龄表明华北板块北部大陆边缘演化历史中,曾于晚元古代末期发生过强烈构造运动,而锡林郭勒杂岩可能是这次构造运动所形成的褶皱变质带,属于华北板块北缘元古宙造山带的组成部分。
Exposed in the Baiyan Tal area near Xilinhot City, the Xilin Gol complex is composed of quartz schists intercalated with amphibolites. In this paper the authors report Sm-Nd and Rb-Sr isotopic data for the amphibolites. Four whole-rock samples yield a Sm-Nd isochron age of 1286 ± 26 Ma, which suggests that the complex was probably formed about 1286 Ma ago. This isochron has a εNd(t) value of 8. 5 ± 0. 6, impling that magma might be derived from a depleted mantle. Five whole-rock samples define a Rb-Sr isochron age of 660 ± 29 Ma. This age is ex-plained as an important tectonic event. The authors suggest that the Xilin Gol complex was a segment of the north continental margin of the North China plate during the middle Proterozoic and underwent a metamorphic and deformation event during the late Proterozoic orogeny.
出处
《地质论评》
CAS
CSCD
北大核心
1997年第1期101-105,共5页
Geological Review
基金
香港霍英东教育基会青年教师基金
关键词
杂岩
原岩年代
变质年代
钕
钐
Xilin Gol complex, Sm-Nd age, Rb-Sr age, Inner Mongolia
