摘要
位于西藏泽当地区的雅鲁藏布江蛇绿岩在我国研究程度较高,该蛇绿岩东西延伸约2000 km,代表了印度和亚洲之间消失的新特提斯洋,是确定上述两大板块间缝合线存在的重要岩石学标志。文章对西藏泽当地区雅鲁藏布江蛇绿岩带中的斜长花岗岩特征及构造环境进行了研究。斜长花岗岩具有钙碱性特征;轻重稀土分异明显,LREE富集,HREE亏损,具有明显的正Eu异常,大离子亲石元素Rb、K、Ba、Sr富集,高场强元素Nb、Ti亏损;地球化学研究表明,斜长花岗岩应形成于俯冲造山的构造环境下,是俯冲洋壳部分熔融的产物,具有岛弧特点。
The Yarlung Zangbo ophiolite located in Zedang region of Tibet is highly studied in China.The ophiolite extends about 2000 km from east to west,representing the disappearing New Tethys Ocean between India and Asia,and is an important petrological marker for the existence of the suture line between the two plates.In this paper,the characteristics and tectonic environment of plagioclase granite in yarlung Zangbo Ophiolite belt in Zedang area,Tibet are studied.Plagioclase granite has calc-alkaline characteristics.LREE enrichment,HREE depletion,positive Eu anomaly,large ion lithophile elements Rb,K,Ba,Sr enrichment,high field strength elements Nb,Ti depletion.The geochemical study shows that the plagioclase granite was formed in the tectonic environment of subduction orogenesis,and is the product of partial melting of subduction oceanic crust,which has the characteristics of island arc.
作者
包国志
张志平
汪宏涛
鲁有朋
晏齐胜
BAO Guo-zhi;ZHANG Zhi-ping;WANG Hong-tao;LU You-peng;YAN Qi-sheng(The Third Institute of Geology and Mineral Exploration,Gansu Provincial Bureau of Geology and Mineral Exploration and Development,Lanzhou 730050,China;Engineering Technology Research Center for Exploration and Comprehensive Utilization of Metal and Precious Metal Mineral Resources of Gansu Province,Lanzhou 730050,China)
出处
《甘肃地质》
2022年第2期8-15,共8页
Gansu Geology
基金
中国地质调查局,西藏乃东县地区1∶5万区域地质调查项目(1212010000150014-46)。
