新疆塞拉加兹塔格岩群霏细斑岩地球化学特征及其年代学意义  

Petrogeochemistry of Felsophyre in Selagaztag,Xinjiang and Its Geochronological Significance

作　　者：陈思尧 袁兆平[1] CHEN Si-yao;YUAN Zhao-ping(Regional Geological Surveying Team,BGEEMRSP,Chengdu 610213)

机构地区：[1]四川省地质矿产勘查开发局区域地质调查队,成都610213

出　　处：《四川地质学报》2021年第S01期20-26,共7页Acta Geologica Sichuan

基　　金：中国地质调查局西安地质调查中心“新疆西昆仑地区1∶5万J44E018003等四幅区域地质矿产调查”(项目编号:12120114054801)。

摘　　要：西昆仑长城系塞拉加兹塔格岩群属于塔里木地层区、铁克里克地层分区,为平行不整合于博查特塔格组之下的细碧角斑岩系。其中酸性火山岩SiO_(2)含量为69.13%~83.01%,Al_(2)O_(3)含量为12.39%~16.08%,K_(2)O/Na_(2)O比值为1.23~3.96,∑REE为325.02×10^(-6)~552.75×10^(-6),LREE/HREE为6.92~10.02,(La/Yb)_(N)=6.17~13.56,(La/Sm)_(N)为6.83~8.21,(Gd/Yb)_(N)为1.13~2.64,δEu为0.27~0.47,稀土配分模式具有上地壳特征。火山岩的沉积学、地球化学及年代学特征显示火山岩形成于青白口纪同碰撞构造环境,为大陆汇聚产物。The Selagaztag Group of the Changcheng System in the west Kunlun Mts.is a set of spilite keratophyre sequence underlain parallelly by the Bochatedage Formation in the Tarim and Tiekelike stratigraphic subregions.The acid volcanic rock contains 69.13%~83.01%SiO^(2),12.39%~16.08%Al_(2)O_(3) with K_(2)O/Na_(2)O ratios of 1.23~3.96,(325.02~552.75)×10^(6)∑REE,LREE/HREE ratios of 6.92~10.02,(La/Yb)_(N) of 6.17~13.56,(La/Sm)_(N) of 6.83~8.21,(Gd/Yb)_(N) of 1.13~2.64 andδEu values of 0.27~0.47 which show that it was derived from the upper crust.The sedimentology,geochemistry and geochronology of the volcanic rocks indicate that they were formed in the syn-collisional tectonic setting.

关 键 词：西昆仑 塞拉加兹塔格群 霏细斑岩 地球化学 锆石U-PB年龄 

分 类 号：P597[天文地球—地球化学]