崔方磊 1汪晓伟 2徐学义 1马中平 2朱小辉 1孙吉明1
作者信息
- 1. 中国地质调查局西安地质调查中心，陕西 西安 710054
- 2. 长安大学地球科学与资源学院，陕西 西安 710064
- 折叠
摘要
Abstract
The diabase-dykesin Carboniferous,featured by relatively higher Al2 O3 and MgO, lower TiO2 ,and deficient P2 O5 and K2 O,are widespread in Qijiaojing-Balikun area in East Tian-shan Mountain,Xinjiang.Analysis on geochemical characteristics show that REE patterns is right ward oblique characterized by LREE enrichment and HREE depletion;trace elements dis-tribution curve demonstrates LILE enrichment in Cs and K,and HFSE depletionin Nb,Ta,Zr and Hf;uniform abundance of SiO2 and LILE fluctuate in significantly;the magma formattingtemperature is close to the interface temperature between asthenosphere and lithosphere,all of the above indicate that the original magma of the diabase-dykes derives from partial melting of en-riched mantle wedge,which is metasomated by liquid or melt;the high Mg# (0.64—0.67),low Ce/Y (1.55—1.79 ) and Dy/Yb (1.97—2.02 ),and the La/Sm-La diagram shows that the primitive magma of the diabase-dykes with a low evolution may come out of high degrees of par-tial melting from garnet-phase peridotite;lazy elements such as Zr,Hf and Y,and discrimination diagrams suggest that the diabase-dykes are probably formed in an intraplate environment.The LA-ICP-MS zircon 206 Pb/238 U age of 314.7±1.5 Ma indicates that Bogda orogenic belt should be extensional environment from late Carboniferous.关键词
辉绿岩脉/锆石U Pb定年/地球化学特征/岩石成因/东天山Key words
diabase-dykes/zircon U-Pb dating/geochemical characteristics/genesis/eastern Tianshan Mountain分类
天文与地球科学
