摘要
东准噶尔扎河坝地区古生代晚期火山岩——原巴塔玛依内山组为一套中基性和酸性火山岩及火山碎屑岩。采用锆石SHRIMP U-Pb同位素定年方法对其中的流纹岩进行定年,年龄为275.6±2.8Ma(MSWD=1.1),表明这套岩石发育于早二叠世。对这套二叠纪火山岩中的玄武岩进行地球化学分析,具有高TiO_2含量、高钾富碱的特点,属于典型的橄榄粗玄岩系列;强烈富集不相容元素和轻稀土元素,显示出源区富集的特点。综合对比新疆北部及邻区(三塘湖地区、红柳河地区、柳园地区及萨吾尔地区)同期的火山岩,扎河坝地区这套二叠纪火山岩形成于后碰撞伸展构造背景,这对研究本地区大地构造格局具有重要的意义。
Latest Paleozoic volcanic rocks, former Batamayineishan Formation in Zhaheba area, eastern Junggar is represented by typical intermediate-basic and acidic volcanic rocks and pyroclastic rocks. The SHRIMP zircon U-Pb data 275.6 +/- 2.8 Ma of rhyolite in the latest Paleozoic volcanic rocks indicated this suite formed in the Early Permian in Zhaheba area. Using geochemical analysis with basalts in the Permian volcanic rocks basalts are belonging to shoshonite, which have high concentration of TiO(2) high K and alkali, and characterized by enriched in light rare earth elements and compatible elements, which indicates an enriched mantle source. Analyzing integrally with Permian volcanic rocks in Northern Xinjiang and its adjacent area (including Santanghu Basin, Hongliuhe area. Liuyuan area and Sawner region), the suite of Early Permian volcanic rocks in Zhaheba area formed in the uniform post-collisional extensional tectonic setting, which is that significant for the geotectonic framework in Zhaheba area.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第3期506-514,共9页
Acta Petrologica Sinica
基金
国家重点基础研究规划项目(2007CB411305)
国家自然科学基金项目(40802047)的资助
