辽宁中沟地区条痕状花岗岩地球化学特征、构造背景及岩石成因意义  

Geochemical Characteristics,Tectonic Setting and Petrogenetic Significance of Striated Granites in Zhonggou Area,Liaoning

作　　者：李研 聂逢君[1] 严兆彬[1] 李宏宇 LI Yan;NIE Feng-jun;YAN Zhao-bin;LI Hong-yu(College of Earth Sciences, East China University of Technology, Nanchang 330013, China;No.240 Institute of Nuclear Industry, Shenyang 110000, China)

机构地区：[1]东华理工大学地球科学学院,南昌330013 [2]核工业二四○研究所,沈阳110000

出　　处：《科学技术与工程》2021年第23期9758-9766,共9页Science Technology and Engineering

基　　金：中国核工业地质局项目(201630)。

摘　　要：辽宁中沟地区大地构造位置隶属于华北克拉通北部。区内岩浆活动频繁,元古代条痕状花岗岩广泛出露,从岩相学、地球化学等方面对中沟地区条痕状花岗岩进行系统分析,目的是探讨该地区构造背景及岩石成因意义。条痕状花岗岩主要为二长花岗岩,岩石中可见钙质和镁铁质角闪石,副矿物为榍石、锆石和磁铁矿,属于高钾钙碱性-钙碱性岩浆系列,A/CNK介于1.09~1.67,A/NK变化于1.11~2.18,为弱过铝质-过铝质岩石。SiO_(2)含量介于61.91~77.48、富碱(Na_(2)O+K_(2)O=1.78~8.58)、高铝(Al_(2)O_(3)=11.57%~19.30%)、低镁钙(MgO=0.07%~2.79%、CaO=0.19%~2.70%)的特征。稀土总量相对较高(ΣREE=109.72×10^(-6)~320.27×10^(-6))、轻稀土分馏系数(La/Sm)N=2.86~10.91,重稀土分馏系数(Gd/Yb)N=0.59~7.97,Eu为中等负异常(δEu=0.18~0.75),在构造判别图解上位于活动大陆边缘区域内,具有明显的俯冲带岩浆特征。结合区域演化历史认为,在古元古代期间,胶辽吉造山带存在向北俯冲的作用。The Zhonggou Area in Liaoning Province is located in the Jiaoliaoji orogenic belt in the north of the North China Craton.There are frequent magmatic activities in the area,and the proterozoic striated granites are widely outcropping in the area.The striated granites in Zhonggou Area were systematically analyzed from the aspects of petrography and geochemistry,in order to discuss the tectonic setting and petrogenetic significance of this area.The sphene granites are mainly monzonite,in which calcium and mafic amphibole are found,and the accessory minerals are sphene,zircon and magnetite,it belongs to the high-K calc-alkaline calc-alkaline series,and its A/CNK ranges from 1.09 to 1.67,and its A/NK ranges from 1.11 to 2.18.It is a weakly peraluminous rock.The content of SiO_(2) is 61.91~77.48,rich in alkali(Na_(2)O+K_(2)O=1.78~8.58),high in aluminum(Al_(2)O_(3)=11.57%~19.30%),low in magnesium and calcium(MgO=0.07%~2.79%,CaO=0.19%~2.70%).Relatively high total rare earth(ΣREE=109.72×10^(-6)~320.27×10^(-6)),light rare earth fractionation factor(La/Sm)N=2.86~10.91,the heavy rare earth fractionation factor(Gd/Yb)N=0.59~7.97,the Eu is moderate negative anomaly(δEu=0.18~0.75),on the tectonic discrimination diagrams in the active continental margin area,has obvious subduction zone characteristics of magma.Combined with the regional evolution history,the Jiao-Liaoji orogenic belt subducted northward during the Paleoproterozoic.

关 键 词：岩相学 地球化学 构造背景 条痕状花岗岩 

分 类 号：P957.3[天文地球—自然地理学]