小兴安岭北段林海林场花岗岩年代学、地球化学特征及构造意义  

Geochronology and geochemistry of granites in Linhai forest farm,northern Xiaoxinganling Mountains:Tectonic implication

作　　者：牟福权 许国雨 卢鸿雁 崔雪文 常亮[1] 娄雨雷 祁迎圣 邱信东 MU Fu-quan;XU Guo-yu;LU Hong-yan;CUI Xue-wen;CHANG Liang;LOU Yu-lei;QI Ying-sheng;QIU Xin-dong(Mudanjiang Natural Resources Comprehensive Survey Center,Mudanjiang 157021,Heilongjiang Province,China;Liaoning Natural Resources Affairs Service Center,Shenyang 110033,China)

机构地区：[1]中国地质调查局牡丹江自然资源综合调查中心,黑龙江牡丹江157021 [2]辽宁省自然资源事务服务中心,辽宁沈阳110033

出　　处：《地质与资源》2025年第1期1-10,102,共11页Geology and Resources

基　　金：黑龙江省国土资源厅项目“黑龙江省逊克县福民林场、永胜经营所幅1∶5万区域地质矿产调查”(HLJKD2006-10).

摘　　要：小兴安岭-张广才岭林海林场地区发育一套高分异I型花岗岩,主要由边缘相细粒二长花岗岩和中心相细中粒二长花岗岩组成.岩石高Si和全碱(Na_(2)O+K_(2)O),富Al,贫Fe、Mg、Ca、Ti,属于准铝质、高钾钙碱性系列岩石,并且富集大离子亲石元素(LILE)、轻稀土元素(LREE),亏损高场强元素(HFSE),具中等强度Eu负异常.花岗岩的LA-ICP-MS锆石U-Pb年龄表明其形成于191.6±2.9 Ma.根据地球化学组成认为,花岗岩主要起源于早中生代浅源陆壳物质的部分熔融.高分异I型花岗岩的发现表明,区内早侏罗世发生过规模较大的岩浆侵入活动,可能与古太平洋板块西向俯冲背景下的区域伸展环境密切相关.A series of highly fractionated I-type granites,mainly composed of marginal facies fine-grained monzogranite and central facies fine-medium-grained monzogranite,is developed in Linhai forest farm area of the Xiaoxinganling-Zhangguangcailing mountains.The granites are characterized by high Si and total alkali(Na_(2)O+K_(2)O),rich Al,and poor Fe,Mg,Ca and Ti,belonging to quasi-aluminous,high-K calc-alkaline series,with enriched LILEs and LREEs,depleted HFSEs,and moderately strong negative Eu anomaly.The LA-ICP-MS zircon U-Pb age results show that the granites were formed at 191.6±2.9 Ma.According to the geochemical compositions,it is considered that the granites are mainly derived from the partial melting of shallow continental crust materials in Early Mesozoic.The discovery of highly fractionated I-type granites indicates that large-scale magmatic intrusion occurred in the Early Jurassic,which may be closely related to the regional extensional environment under the westward subduction of paleo-Pacific plate.

关 键 词：早侏罗世 花岗岩 地质年代学 地球化学 构造背景 小兴安岭 张广才岭 

分 类 号：P597[天文地球—地球化学]