西藏拉萨冈底斯岩带中酸性岩类的Rb-Sr同位素研究  

A STUDY ON Rb-Sr ISOTOPES IN THE INTERMEDIATE-ACID ROCK BODIES OF THE GANGDISE ROCK BELT, LHASA, XIZANG

作　　者：桂训唐 成忠礼 王俊文 

出　　处：《地球化学》1982年第3期217-225,共9页Geochimica

摘　　要：The Gangdise rockk belt is the northmost an4 petrochemically the most complex one of the three east-west striking intermedlate-acid rock belt in south Xizang. Rh-Sr whole rock isochronous dating was conducted on samples of different rocks collected aerossing this belt from Quxur throwgh Lhasa to Yangbajan, Results show that these rocks are not contemporaneous and can be roughly assigned to four periods: Indosinian (240±30 my), Early Yenshanian (160--180my), Late Yenshanian (80--100 my), and Himalayanian (20-40 my). Their initial ratios of Sr isotopes are relatively low (0.7033--0.7054). The relationship between Rb, Sr and the major components such as SiO2, K2Oand FeO are also investigated. It seems that, the formation and development of the Gangdise belt can be obviously related with the subduction and collision of the Indian plate with the Eurasian plate. The material that formed this rock belt probably originated from the upper marital or the partial molten products from oceanic crust.The Gangdise rock belt is the northmost and petrochemically the most complex one of the three east-west striking intermediate-acid rock belt in south Xizang. Rb-Sr whole rock isochronous dating was conducted on samples of different rocks collected acrossing this belt from Quxur through Lhasa to Yangbajan. Results show that these rocks are not contemporaneous and can be roughly assigned to four periods: Indosinian (240±30 my), Early Yenshanian (160-180my), Late Yenshanian (80-100my), and Hi-malayanian (20-40 my). Their initial ratios of Sr isotopes are relatively low (0.7033-0.7054). The relationship between Rb, Sr and the major components such as SiO2, K2O and FeO are also investigated. It seems that the formation and development of the Gangdise belt can be obviously related with the subduction and collision of the Indian plate with the Eurasian plate. The material that formed this rock belt probably originated from the upper mantal or the partial molten products from oceanic crust.

关 键 词：中酸性岩 RB-SR同位素 冈底斯岩 西藏 

分 类 号：P588.121[天文地球—岩石学] P597[天文地球—地质学]