北山地区花岗岩类成因的Nd同位素制约  

Nd-Isotope Constraints on Origin of Granitoids in Beishan Mountain Area

作　　者：江思宏[1] 聂凤军[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质学报》2006年第6期826-842,共17页Acta Geologica Sinica

基　　金：国土资源大调查项目(编号K1.3.32和200310200001-01)资助成果。

摘　　要：北山地区地处中亚造山带的中东部,花岗岩类分布广泛,但是长期以来,对该区花岗岩缺少系统的 Nd同位素研究。本文在以往工作基础上,通过大量的Nd同位素分析,发现北山地区花岗岩类的εNd(t)值变化于 -16．39-+7．85,不少花岗岩类具正εNd(t)值,说明本区与中亚造山带上其他地区一样,在显生宙存在大规模的地壳生长。与新疆北部、内蒙占东部和大兴安岭地区相比,北山地区花岗岩类的εNd(t)值具有更大的变化范围,也更偏负值,这可能与该区产出有大量的前寒武纪变质岩有关。Located in the central-east part of the Central Asian Orogenic Belt （CAOB）, the granitoids are widely distributed in Beishan Mountain area, with an outcrop area more than 30,0000 km^2. The Nd isotope of the granitoids, however, lacks systematic study. Based on the previous geological work, a large number of granitoid samples are carried on the Sm-Nd isotopic analysis. The results show that the ENd （t） values of these granitoids occurred in Beishan Mountain area range from -16.39 to ＋ 10. 89, some of which are characterized by the positive ENd（t） value. It suggests that the crustal growth existed during Phanozoic in Beishan Mountain area, just like other regions in the CAOB. Comparing with those in northern Xinjiang, eastern Inner Mongolia and Great Hinggan, the granitoids in Beishan Mountain area have much larger range of ENd （t） values, and are more negative, which may be related to the voluminous Precambrian metamorphic rocks exposed in this area.

关 键 词：花岗岩类 ND同位素 北山 

分 类 号：P588.13[天文地球—岩石学]