摘要
通过对龙王山灰白色细粒石英闪长岩和灰白色细粒二长花岗岩样品进行LA-ICP-MS锆石UPb测年结果属于晚志留世侵入岩。岩石地球化学特征表明,为高钾过铝质-准铝质碱钙性岩;稀土元素Eu具有弱负异常特征;微量元素中Ta、Nb、Zr、Sr、Ti、P相对贫化,Rb、Th、Hf、Ba、Sc、K、Ce、Nd、Sm含量相对富集。Rb/Sr平均值为0.30,介于上地幔值与地壳值之间,反映出壳幔源的特点,为S型花岗岩。综合分析该期花岗岩是弧陆碰撞向陆陆碰撞转化阶段构造背景下形成的同碰撞花岗岩。
According to LA-ICP-MS zircon U-Pb dating on samples of linen line-gram quartz alortte ana llIlel1 fine-grain monzonitic granite in Longwang Mountain, they are late Silurian intrusive rocks. Lithogeochemica~ characteristics show that they are high potassic peraluminous -metaluminous alkalic calcic rocks; REE ele ment Eu has characteristics of weak negative anomaly; trace elements of Ta, Nb, Zr, Sr, Ti and P are rela tively depleted, and contents of Rb, Th, Hf, Ba, Sc, K, Ce, Nd and Sm are relatively enriched. The aver age value of Rb/Sr is 0.30, which is between upper mantle value and crustal value. It reflects the character istics of crust-mantle source and it is S type granite. The comprehensive analysis shows that the granites in this phase are syn-collisional granites under the tectonic settings of transferring phase from arc-continent col lision to continent-continent collision.
出处
《矿产与地质》
2013年第6期462-470,508,共10页
Mineral Resources and Geology
基金
中国地质调查局地质调查项目<青海省1:5万玉龙滩
抓什究
贺尔
桥头幅区域地质调查>(项目编号:1212011121192)
