摘要
针对东昆仑拉陵灶火地区产出的二长花岗岩进行锆石LA-ICP-MS U-Pb同位素年代学研究,结果表明,该岩体的形成年龄为396.2 Ma±2 Ma,时代为中泥盆世早期。岩石地球化学研究表明该岩石具有硅含量和全碱含量高特征,准铝质,稀土含量中等,强Eu亏损,呈"燕式"稀土配分模式,微量元素蛛网图上出现Ba、Sr-P和Eu-Ti 3个明显的低谷,结合花岗岩成因类型判别图解确定其为A2型花岗岩。综合区域上的研究成果,东昆仑造山带早中泥盆世花岗岩组合、基性岩墙群及A型花岗岩可能都是后碰撞阶段持续的或间歇的伸展体制下的产物,也表明该阶段是区域构造转换的关键时刻。
LA-ICP-MS U-Pb isotope dating of monzonitic granite occurred in Lalingzaohuo area of East Kunlun gives an age of 396.2Ma±2Ma,corresponding to middle Devonian Period.Geochemical studies show that the granite is characterized by high silicon and total alkalis content,metaluminous,medium rare earth content with intensive depletion of Eu and＂Yan＂ REE patterns.In spider diagram,Ba,Sr-P and Eu-Ti displays three apparent trough.Based on above geochemical data,combined with the granites type discrimination diagrams,the monzonitic granite can be classified into A2-type granite.Regional geological synthesis suggests that the granite assemblage,mafic dikes,A type granites of Early-Middle Devonian are probably the production of continuous or intermittent extensional system,implying that Early-Middle Devonian period is a transformation period of tectonic setting.
出处
《矿物岩石》
CAS
CSCD
北大核心
2013年第2期26-34,共9页
Mineralogy and Petrology
基金
973计划前期研究专项课题(2010CB434808)
青海省科技支撑计划(2011-J-113A)
青海省自然科学基金(2012-Z-934Q)
