资源描述：
《南秦岭晚三叠世胭脂坝岩体岩石磁学及磁组构可靠性约束.pdf》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、第35卷第9期地质通报Vol.35,No.92016年9月GEOLOGICALBULLETINOFCHINASep.,2016南秦岭晚三叠世胭脂坝岩体岩石磁学及磁组构可靠性约束11222牛广智，陶威，梁文天，李阳，冉亚洲11222NIUGuangzhi,TAOWei,LIANGWentian,LIYang,RANYazhou1.陕西区域地质矿产研究院，陕西咸阳712000；2.西北大学地质学系/大陆动力学国家重点实验室，陕西西安7100691.AcademyofRegionalGeologicalSurveya
2、ndMineralResourcesExplorationofShaanxi,Xianyang712000,Shaanxi,China;2.DepartmentofGeology/StateKeyLaboratoryofContinentalDynamics,NorthwestUniversity,Xi’an710069,Shaanxi,China摘要：胭脂坝岩体是秦岭造山带内具典型代表性意义的晚三叠世花岗岩，已有的年代学和地球化学研究对该岩体的侵位机制有不同认识。对岩体的岩石磁学进行分析，结合其岩相学特征，探
3、讨了用磁组构约束岩体内部组构这一方法的可靠性。研究表明，胭脂坝岩体样品的平均磁化率Km值和校正磁化率各向异性度PJ值总体较低，与顺磁性花岗岩类一致。磁滞回线分析表明，绝大部分样品的磁化率来自顺磁性矿物的贡献，少部分高磁化率样品含有铁磁性矿物的贡献，但其浓度极低。高磁化率值样品的等温剩磁曲线获得和反向退磁曲线及χ-T曲线分析表明，铁磁性矿物为磁铁矿，且为多畴颗粒。结合岩相学特征，认为胭脂坝岩体低场磁组构反映了顺磁性的云母类矿物的组构特征，磁组构特征真实地记录了样品的内部组构特征。关键词：AMS；IRM；磁滞回线；
4、热磁曲线；铁磁性矿物；顺磁性花岗岩中图分类号：P534.51文献标志码：A文章编号：1671-2552（2016）09-1522-07NiuGZ,TaoW,LiangWT,LiY,RanYZ.MagneticmineralogyandfabricreliabilityconstraintsofLateTriassicYanzhi⁃baplutoninSouthQinlingMountain.GeologicalBulletinofChina,2016,35(9):1522-1528Abstract:TheYan
5、zhibaplutonisoneofthetypicalLateTriassicgraniteplutonsinQinlingMountain,andlotsofgeochronologicalandgeochemicalworkhasbeendonefortheYanzhibagraniteplutoninSouthQinlingMountainrecently.However,opinionsofitstectonicsettingsarecontradictory.Somerecentstudieshav
6、eplacedsomenewconstraintsonthisproblembasedonthemagneticfab⁃ricsofthesegraniteplutons.Thesestudieshavesuccessfullyelucidatedthecorrelationbetweenregionaltectonicsandgraniteemplace⁃ment.However,thereliabilityofthemagneticfabricmethodhasnotbeenspecificallystud
7、ied.Inthispaper,theauthorspresentanelaboratemagneticmineralogyanalysis,combinedwithpreviouspetrographicaldata,toshedlightonthisproblem.Meansusceptibili⁃tyKmandcorrectedanisotropydegreePJofYanzhibaplutonarelow,whichareconsistentwithdataofparamagneticgranite.H
8、ystere⁃sisloopsshowthatsusceptibilityofmostsamplesoriginatesfromparamagneticminerals,withasmallportionofferrimagneticcontri⁃bution,whoseconcentration,however,isverylow.Isothermalremanentmagnetiz
