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ID:33017918
大小:3.93 MB
页数:59页
时间:2019-02-19
《青海省天峻南山蛇绿岩套特征分析-(6239)》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、AbstractTianjunNanshaninwesternQinghaiprovinceislocatedintheNorthChinaplate,southernQiliantectonicbeltandthenorthernmarginofthenorthernmarginoftheQaidamBasinbindingsiteZongwulongorogenicbelt.ZongwulongorogenicbeltistheSouthernQilianblockandthenorthernmargi
2、noftheQaidamBasinblockinthePaleozoiccollisionfunctionproduct,NWWdirectionlineartectonicbelt.TianjunNanshanophioliteinQinghaiprovinceinthestudyareaisnotcontinuouslyexposed.EachunitofophioliteinthetectonicrocksheetformoccursinTianjunNanshanophioliticmelangeB
3、elt.Ophiolitesequencethroughouttherockrecoveredisbasicallyintact.TianjunNanshanophiolitebeltisabout19kilometerslong,200~3000meterswide,theexposedareaofabout25squarekilometers.Controlledbyfaults,theNorthLarizhaafaultastheboundarywithsouthernQilianorogenicbe
4、ltinthelateTriassicGroupRivers(Tj)contactwithinfault.OnthesouthsideareinfaultcontactwiththeCarboniferousGuokeshangroup(Cgk)clasticrockandcarbonaterockstrata.TianjunNanshanophioliteassemblagescomposedofdifferentrockblocks,mainlyincludingintenseserpentinizat
5、ionmetamorphosedpureperidotite,peridotite,gabbros,basiclava(deep-seachert)andsiliceousrock.ThebasaltsofTianjunNanshanophiolitebelongtocalcalkalinerock,withthetholeiiteseries,chemicalcharacteristicsoflowKandhighTirocks.Themaficdykesandcumulatesgabbrosbasicl
6、avarockwiththesamechemicalcharacteristics.Metamorphicultrabasichaveperidotitefeaturesoftypicalophiolitein,theircommongeochemicalcharacteristicsreflectingthattheyaremembersofthesameophiolitesuiteinthefamily.Thedifferentrockcombinationproductformationbelongs
7、tothesametectonicenvironment.TianjunNanshanophiolitetotalcontentofREEislow.Metamorphicperidotiteisthelowest,thetotalREEisslightlyhighorclosetomidoceanridgeophiolite.REElineisnotexactlythesameofmidoceanridgeophiolite.TheREElineisclosetooceanislandophiolite.
8、TraceelementsaregenerallyenrichedinLILelements,butlossofHFSelements.8786TheophiolitemaficlavaandmaficdykeswarmsofSr/Sr(0.7037~0.703852)ratioisclosetotheratiooftypicaloceanislandbasalt,andslightlyhigherthanthe
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