大别山北部桃花岭岩体年代学、地球化学特征及构造意义  

Zircon Geochronology and Geochemistry of the Taohualing Pluton in Northern Dabieshan and Their Tectonic Implications

作　　者：袁德志[1] 唐相伟[1] 史兴俊 包峻帆 刘奎松[1] 范金伟 郭跃闪 YUAN Dezhi;TANG Xiangwei;SHI Xingjun;BAO Junfan;LIU Kuisong;FAN Jinwei;GUO Yueshan(No.3 Institute of Geological and Mineral Resources Survey,Henan Bureau of Geoexploration and Mineral Development,Xinyang 464000,China;College of Geographic Sciences/Southern Henan Center for Mineral Rock and Gem-Jade Identification and Processing,Xinyang Normal University,Xinyang 464000,China)

机构地区：[1]河南省地质矿产勘查开发局第三地质矿产调查院,河南信阳464000 [2]信阳师范学院地理科学学院/豫南岩矿宝玉石鉴定及加工中心,河南信阳464000

出　　处：《信阳师范学院学报（自然科学版）》2022年第1期97-102,共6页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(41802239);河南省两权价款地质科研项目(豫国土资函[2015]258号);河南省科技攻关项目(192102310268)。

摘　　要：由于缺少可靠的年代学资料和系统研究,大别山北部桃花岭岩体的时代和成因背景尚不清楚。MC-ICP-MS锆石U-Pb分析结果显示,桃花岭正长花岗斑岩侵位于154±1 Ma,花岗闪长岩侵位于142±1 Ma,表明桃花岭岩体是形成于侏罗纪末-早白垩世的复式岩体。地球化学分析表明,桃花岭花岗岩为高钾钙碱性、准铝质-弱过铝质的I型花岗岩。这些花岗岩都相对富集轻稀土,亏损重稀土,同时具有高Sr低Y和弱的Eu负异常(0.7~0.8),类似低镁埃达克质岩石,代表了加厚下地壳熔融的产物。Due to the lack of detailed field geological and high-precision geochronological studies,the age and tectonic setting of the Taohualing pluton have been poorly understood so far.Zircon U-Pb of MC-ICP-MS dating yields the mean age of 154±1 Ma and 142±1 Ma for the syenogranite-porphyry and granodiorites,respectively,which indicates that the Taohualing pluton is a composite granite formed in the late Jurassic-early Cretaceous.The Taohualing granites are metaluminous to slightly peraluminous and high-K calc-alkaline,belonging to the I-type granites.Besides high Sr and low Y contents,the REE patterns of all the rocks show enrichment in LREEs relative to HREEs and weakly negative Eu abnormal.These geochemical characteristics are similar to the low-Mg adakitic rocks,and can be best explained by deep melting of a thickened lower continental crust.

关 键 词：大别造山带 花岗岩类 桃花岭岩体 锆石年代学 埃达克质岩 

分 类 号：P581[天文地球—岩石学]