| 摘要: |
| 1:25万区域地质调查工作中,于当惹雍错中部的吉松一带发现环斑花岗岩,获同位素K-Ar法年龄45.3 Ma,时代为始新世。吉松环斑花岗具特殊的卵状环斑结构,K2O+Na2O含量较高,K2O>Na2O;稀土元素含量高,具明显的铕亏损,为造山型环斑花岗岩,形成于青藏高原陆内碰撞造山晚期的后碰撞环境。 |
| 关键词: 当惹雍错 吉松 环斑花岗岩 始新世 西藏 |
| DOI： |
| 附件 |
| 投稿时间：2005-03-02修订日期：2006-04-08 |
| 基金项目:中国地质调查局“1:25万邦多幅区域地质调查”。 |
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| The discovery and significance of the rapakivi granites in Gyisong,Tangra Yumco,Xizang |
| CHEN Zhen-hua, LIU Yun, LI Jun-liang |
| (Jiangxi Institute of Geological Survey, Nanchang 330201, Jiangxi, China) |
| Abstract: |
| The rapakivi granites were discovered during the 1:25 000 regional geological survey in Gyisong, Tangra Yumco, Xizang. These granites give a K-Ar age of 45.3 Ma and may be traced back to the Eocene. They are characterized by special oval rapakivi textures, higher K2O +Na2O contents, K2O >Na2O, higher REE contents and depletion of the element Eu, and thus belong to the orogenic rapakivi granites originated from the intracontinental post-collisional settings during the later stages of collision and mountain building of the Qinghai-Xizang Plateau. |
| Key words: Tangra Yumco Gyisong rapakivi granite Eocene Xizang |
