摘要
笔者从同位素 U-Pb 及 Rb-Sr 测年、稀土元素地球化学资料出发,探讨了川西北几个花岗岩体的形成年代和成因。
Rock samples were collected from several granite plutons in northwestern Sichuan on thebasis of more recent field observations.Four samples were dated for zircon U-Pb ages,twosamples were determined for Rb-Sr isochron ages and six samples were analyzed for rare-earthelements.The Nianbaoyeze grainte was dated at 152 Ma,with an initial ^(87)Sr/^(86)Sr ratio of0.72767,belonging to continental crust-reworked granites.The Kéerying pluton is a compositeone,with porphyroid biotite granitoids being formed earliest at 204 Ma,followed by biotitegranitoids which were formed at 201—204 Ma,and two-mica granitoids being the latest phasedated at 116 Ma,with an initial ^(87)Sr/^(86)Sr ratio of 0.71152,belonging to continental crust-rework-ed granitoids.The Manai pluton was formed at 202 Ma or at 206 Ma,designated to meta-morphic-metasomatic granitoids.The Gezong pluton was formed at 841 Ma,belonging tometamorphic-metasomatic granitoids.
出处
《地球化学》
CAS
CSCD
北大核心
1993年第3期303-312,共10页
Geochimica
