辽东岫岩地区晚侏罗世侵入岩的年代学、地球化学特征及地质意义  

Geochronology,Geochemistry,and Geological Significance of Late Jurassic Intrusions at Xiuyan,Eastern Liaoning Province

作　　者：王玉平 吴文彬 刘永俊 李海洋 王晓亮 李超 WANG Yuping;WU Wenbin;LIU Yongjun;LI Haiyang;WANG Xiaoliang;LI Chao(Liaoning Instiute Co.Ltd.of Geology&Mineral Resources,Shenyang,Liaoning 110032,China)

机构地区：[1]辽宁省地质矿产研究院有限责任公司,辽宁沈阳110032

出　　处：《现代地质》2021年第4期955-967,共13页Geoscience

基　　金：中国地质调查局项目“辽东-吉南成矿带永吉-凤城地区地质矿产调查”(DD20160049)。

摘　　要：对辽东岫岩地区锉草沟黑云母二长花岗岩、刘家堡子二云母二长花岗岩进行了岩相学观察、LA-ICP-MS锆石U-Pb年代学和地球化学测试。测年结果显示锉草沟黑云母二长花岗岩的锆石年龄为(162.7±2.5)Ma,刘家堡子二云母二长花岗岩锆石年龄为(156.9±1.1)Ma,均形成于晚侏罗世。两个岩体具有相似的地球化学特征,主量元素具有富Si、Al和K以及贫Fe、Mg和Ca的特征,A/CNK值为1.01~1.15,A/NK值为1.13~1.33;微量元素亏损Nb、P和Ti等高场强元素,富集Rb、K和Hf等不相容元素,(La/Yb)_(N)为7.10~41.13,Eu无负异常,具有高Sr(128×10^(-6)~454×10^(-6))、低Y(3.03×10^(-6)~12.10×10^(-6))和Yb(0.40×10^(-6)~1.32×10^(-6))特征,表现为具有埃达克质亲和性的过铝质I型花岗岩。结合两个岩体的时空特点分析认为,在晚侏罗世时期,辽东岫岩地区花岗质岩浆作用的发生是太平洋Izanaqi板块向西俯冲、西伯利亚板块与华北板块碰撞挤压造成地壳增厚,进而引发下地壳物质部分熔融的结果。Petrographic and geochemical data and LA-ICP-MS zircon U-Pb ages have been obtained for the Cuo-caogou biotite monzogranites,Liujiapuzi two-mica monzogranites at Xiuyan,eastern Liaoning Province.LA-ICP-MS zircon U-Pb ages of the Cuocaogou biotite monzogranites(162.7±2.5 Ma)and Liujiapuzi two-mica monzogranites(156.9±1.1 Ma)indicate that the granitoid emplacement occurred in the Late Jurassic.Two kinds of intrusions have the same geochemical characteristics,with their major element contents featured by high Si,Al,and K,but low Fe,Mg,and Ca.The rocks have A/CNK=1.01-1.15 and A/NK=1.13-1.33.Trace elements are enriched in incompatible elements such as Rb,K,and Hf,but depleted in Nb,P,and Ti.The rocks have(La/Yb)_(N)=7.10-41.13,and have no discernible Eu anomaly.With high Sr(128×10^(-6)-454×10^(-6))and low Y(3.03×10^(-6)-12.10×10^(-6))and Yb(0.40×10^(-6)-1.32×10^(-6))features,the.rocks show adakitic and peraluminous I-type affinity.Combined with spatial-temporal characteristics of the two plutons,magmatism at Xiuyan was likely formed in a continental crustal thickening setting,which may have been related to the Paleo-Pacific(Izanaqi plate)subduction when the Siberian and North China plate collided.This may have induced partial melting of lower crustal materials.

关 键 词：辽东岫岩 晚侏罗世侵入岩 锆石U-PB测年 过铝质I型花岗岩 埃达克质岩石 

分 类 号：P588.12[天文地球—岩石学] P595[天文地球—地质学]