西藏当惹雍错吉松环斑花岗岩的发现及地质意义

基金项目:

中国地质调查局“1:25万邦多幅区域地质调查”。

详细信息

The discovery and significance of the rapakivi granites in Gyisong,Tangra Yumco,Xizang

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。
- 当惹雍错 /
- 吉松 /
- 环斑花岗岩 /
- 始新世 /
- 西藏
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.
- Tangra Yumco /
- Gyisong /
- rapakivi granite /
- Eocene /
- Xizang