摘要
西藏定结地区高喜马拉雅隆起带中淡色花岗岩体紧靠藏南拆离断层内呈等轴状小岩株产出。淡色花岗岩地球化学特征为过铝质,高Si和K,低Ca、Fe和Mg,岩石富轻稀土元素及Rb、Ba和Th,贫Hf、Zr、Y和Yb,呈现S型花岗岩特征。基底副变质岩中广泛发育淡色花岗岩脉体,在副变质岩中的淡色花岗岩脉体内发现紫苏辉石暗色麻粒岩残留体,通过对淡色花岗岩与基底副变质岩的地球化学特征的对比,发现它们具有相似的稀土元素配分曲线,均富K、Rb、Ba和Th,贫Hf、Zr、Y和Yb。认为基底副变质岩为高喜马拉雅淡色花岗岩源岩,其在快速隆升降压的条件下发生缺水熔融生成淡色花岗岩浆而残余麻粒岩残留体。
Leucogranites in the high Himalayan uplifting belts,Dingjie area,Tibet,are very close to the inner South Tibet detachments and occur in a series of small stocks.Geochemical constraints show that they are peraluminous Stype granites with high Si,K,LREE,Rb,Ba,Th,and low Ca,Fe,Mg,Hf,Zr,Y,Yb.Their veins were widespreadly formed in the basal parametamorphic rocks of the High Himalayan crystallines and the hypersthene granulite restites were found in these veins.The leucogranites and parametamorphic rocks in the basement have similar REE patterns,and both are rich in K,Rb,Ba,Th and poor in Hf,Zr,Y,Yb.It is suggested that the source rocks of the leucogranites are parametamorphic rocks in the basement in the High Himalayan uplifting belts, and parametamorphic rocks in the basement under the fluidabsent condition,generting leucogranitic melts and granulitefacies residues with uplifiting and dcompressing of the High Himalayan basement.
出处
《地质科技情报》
CAS
CSCD
北大核心
2003年第3期9-14,共6页
Geological Science and Technology Information
基金
中国地质调查局项目"定结县幅陈塘区幅(中国部分)1:25万区域地质调查"(2001300009231)
