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西南天山巴什索贡岩体岩石地球化学特征及地质意义
The Geochemical Characteristics and Geological Significance of Bashisuogong Pluton in Southwest Tianshan
【摘要】 西南天山巴什索贡岩体侵位于下二叠统巴立克立克组中。该岩体主要由辉长岩、石英正长岩及碱长花岗岩组成。从岩石化学等资料分析,辉长岩Si O2含量46.16%~53.89%,为基性岩类,石英正长岩及碱长花岗岩Si O2含量为60.92%~74.6%,属酸性岩类,三者铝饱和指数A/CNK<1.1,岩石类型均为偏铝质花岗岩。采用等离子体质谱-激光探针法(LA-ICP-MS),在辉长岩中和石英正长岩中获得锆石U-Pb年龄值分别为(273.95±0.85)Ma、(268.9±1.0)Ma,时代为中二叠世,代表巴什索贡岩体的生成年龄。辉长岩、石英正长岩及碱长花岗岩为碱钙性系列岩石,发生在碰撞后的张驰阶段,该期岩体的构造环境为板内拉伸环境下产物,具有板内裂谷特征。
【Abstract】 The Bashisuogong pluton mass of Southwest Tianshan invaded in the Balikelike formation of lower Permian.The pluton is mainly composed of gabbro,quartz-syenite and alkalic feldspar granite.The analysis of the petrochemistry data shows that Si O content of gabbro is 46.16%~53.89%2,it belongs to the basic rocks,quartz syenite and alkalic feldspar granite vary form Si O content range from 60.92% to74.6%,it belongs to acid 2rocks,Sapples aluminum saturation index A / CNK <1.1, indicated the type of the rock is partial aluminous granite.Using the method of LA-ICP-MS,we obtained zircon U-Pb age of gabbro and quartz-syenite values were(273.95±0.85) Ma、(268.9±1.0)Ma,it belongs to Permian,which can be interpreted as formation age of Bashisuogong pluton, Gabbro、quartz syenite and alkali feldspar granite are alkali calcium series of rocks,they were formed in the stress relaxation phase after the collision.The tectonic environment of the pluton is the product of the intraplate extensional environment, characterized by a intraplate rift.
【Key words】 Southwest Tianshan; Bashisuogong pluton; Zircon U-Pb dating; Geochemical characteristics;
- 【文献出处】 新疆地质 ,Xinjiang Geology , 编辑部邮箱 ,2016年01期
- 【分类号】P588.1
- 【网络出版时间】2016-04-14 18:13
- 【下载频次】48