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ID:51413508
大小:3.27 MB
页数:12页
时间:2020-03-23
《内蒙古北山地区月牙山蛇绿质构造混杂岩带地质特征、形成时代及大地构造意义.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34卷第2~3期地质通报Vo1.34.Nos.2~32015年3月GEoLoGICALBULLETINoFCHINAMar.,2015内蒙古北山地区月牙山蛇绿质构造混杂岩带地质特征、形成时代及大地构造意义胡新茁,赵国春,胡新悦。,廖云峰。,程海峰。HUXinzhuo,ZHAOGuochun,HUXinyue,LIAOYunfeng2CHENGHaifeng,1.中国地质大学(北京),北京100083;2.河北省区域地质矿产调查研究所,河北廊坊0650001.ChinaUniversityofGeoscierwes,Beifng100083,China;2
2、.RegionalGeologicalandMineralResourcesSurveyInstituteofHebeiProvince,Langfang065000,Hebei,China摘要:月牙山蛇绿质构造混杂岩带位于红柳河一洗肠井蛇绿岩带东部的月牙山一带。月牙山蛇绿岩套出露较完整,自下而上由超基性杂岩、辉长岩、层状玄武岩、枕状玄武岩及放射虫硅质岩组成。蛇绿岩套北侧发生了强烈的构造混杂作用,形成蛇绿质构造混杂岩带,由强糜棱岩化、强蛇纹石化的辉橄岩、玄武岩基质和辉石岩、堆晶辉长岩、斜长花岗岩、橄榄岩、橄辉岩、角闪石岩、白云岩、放射虫硅质岩、蚀变玄武岩等
3、岩块组成。通过对蛇绿岩套中辉石岩、辉长岩、斜长花岗岩、辉长闪长岩及蛇绿岩套北侧斜山——东七一山火山弧中的安山岩、花岗闪长岩等开展锆石u—Pb同位素测年研究,确定月牙山蛇绿岩套形成时代约为530Ma,相当于早寒武世;洋盆发生犬规模自南向北俯冲作用的时间为421.0+15-442.4+1.5Ma,相当于志留纪。通过对蛇绿岩带两侧地层形成环境及蛇绿岩带对两侧地层单位的限定意义等研究认为,红柳河一洗肠井蛇绿岩带是代表古大洋闭合的板块缝合带,以该带为界,北侧为哈萨克斯坦板块,南侧为塔里木板块。关键词:蛇绿岩;蛇绿质构造混杂岩;地质特征;形成时代;大地构造意义中图分类
4、号:P588.3;P597~.3文献标志码:A文章编号:1671—2552(2O15)02/03—0425—12HuXZ,ZhaoGC,HuXY,LiaoYF,ChengHF.Geologicalcharacteristics,formationepochandgeotectonicsignificanceoftheYueyashanophiolitictectonicm61angeinBeishanarea,InnerMongolia.GeologicalBulletinofChina,2015,34(2/3):425-436Abstract:TheYu
5、eyashanophiolitetectonicmelangebeltislocatedintheHongliuhe——XichangjingophiolitebeltofeasternYueyas-hanarea.Yueyashanophiolitesuiteisexposedcompletely,composedfromthebottomupwardofultrabasiccomplex,gabbro,lay—eredbasaltandpillowbasaltaswellasradiolariansiliceousrocks.Onthenorthems
6、ideoftheophiolitesuitetherehappenedintensetectonicmelangeactivity,formingtheophiolitetectonicmelangebeltcomposedmainlyofstronglymylonitizedandserpentinizedpyroxeneperidotite,basaltmatrix,pyroxenite,cumulategabbro,plagioclasegranite,peridotite,olivinegabbro,homblendite,dolo-mite,ra
7、diolariansiliceousrocks,andalteredbasalt.TheauthorscarriedoutzirconU—Pbisotopicdatingofophiohtesuitepyroxe—nite,gabbro,plagioclasegraniteandgabbrodiorite.Inaddition,theauthorsconductedU—PbisotopeexperimentsonandesiteandgranodioritederivedfromtheXieshan—Dongqiyishanvolcanicarconthe
8、northernsideoftheophiohtesuite.Th
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