新疆西天山天山乡南部片麻状花岗闪长岩锆石U-Pb年代学、地球化学特征及构造意义  

Zircon U-Pb Geochronology,Geochemical Characteristics and Tectonic Implication of the Granodiorite in the Southern Tianshan,Xinjiang

作　　者：杨宏图[1] 鞠林雪[1] 刘婷婷 刘军省[1] 邓宇飞[1] Yang Hongtu;Ju Linxue;Liu Tingting;Liu Junxing;Deng Yufei(Geological Research Institute of China Chemical Geology and Mine Bureau,Zhuozhou,Hebei,072750,China;China Chemical Geology and Mine Bureau,Beijing,100013,China)

机构地区：[1]中化地质矿山总局地质研究院,河北涿州072750 [2]中化地质矿山总局,北京100013

出　　处：《新疆地质》2017年第3期235-244,共10页Xinjiang Geology

基　　金：中国地质调查局国土资源大调查项目(12120115021201)

摘　　要：新疆西天山天山乡地区大面积分布片麻状花岗闪长岩,含较高的Na_2O+K_2O,A/CNK为0.74~0.97,为准铝质、钠质,成因类型为I型花岗岩,稀土元素富集、重稀土亏损的右倾型分布模式,δEu在弱片麻状似斑状花岗闪长岩中呈中等负异常,在强片麻状花岗闪长岩中基本无异常;微量元素总体富集大离子亲石元素,亏损高场强元素,Ba,Rb,K,Nb,Ta,Ti元素呈明显的亏损特征,具岛弧火山岩特征;锆石U-Pb年龄为(321.9±1.2)Ma,为早石炭世晚期。综合野外地质观察、区域地质构造,认为天山乡南部片麻状花岗闪长岩形成于南天山洋闭合时期,岛弧基本消亡逐渐向陆陆碰撞的过渡阶段。A large area of distributed granodiorite in the West TianShan of Xinjiang,containing higher Na2O+K2O,A/CNK 0.74～0.97,is quasi alumina,Sodic,the genetic type is I type granite;REE enrichment,the heavy REE behave as right deviation allocation model;δEu in weakly foliated porphyritic granodiorite showes moderate negative anomaly,there is no anomaly in the strong granulite granodiorite.General enrichment of trace elements with large ion affinity stone elements,loss of high field elements.Ba,Rb,K,Nb,Ta,Ti elements showed obvious loss characteristics,characterized by island arc volcanic rocks.The zircon U-Pb age is(321.9+1.2)Ma,which belongs to late carboniferous.Comprehensive geological observation,regional geological structure,southern Tianshan Xiang gneissic granodiorite formed in the South Tianshan ocean closure period,arc largely vanished gradually to the collision of the transition phase.

关 键 词：西天山 片麻状花岗闪长岩 LA-ICPMS锆石U-PB定年 岩石地球化学 构造环境 

分 类 号：P588.1[天文地球—岩石学] P597.3[天文地球—地质学]