板块构造理论超大陆旋回与威尔逊旋回构造supercontinentcyclisityandwilsoncycl

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1、2)SuperContinentcyclisity(?)andWilsoncycletectonicsDoestheearth’scontinentallithospheregothroughstagesofassemblyanddisintegrationtoproduceperiodswhenmostcontinentsareunitedintoone,aSupercontinent?.TheWilsonCycle:namedafterJ.TuzoWilson,oneofthefoundingfathersofplate-tectonicsa

2、nddiscovereroftransformfaults.Wilsonusedhisreferencebackground,intheNorthAtlanticrealmandtheAppalachian-CaledonianorogenicbeltsonbothsidesoftheAtlanticoceantoformulateahypothesissayingthatthebuildingofmountainbeltshaveacloserelationshiptotheopeningandclosureofoceanswithoceani

3、clithosphere.Henceheintroducedtheterm”theProto-Atlantic”asanameforthepostulatedoceanthataccordingtothemodelonceopenedandclosedtoproducetheAppalachiansandtheCaledonidesTraditionalWilsoncyclemodel:Orthogonalopeningandclosurelikeonthepreviousslide,two-dimensionalmodels.ModifiedW

4、ilsoncyclemodel:Wilson-cycletypetectonicswithamodernapproach;---oneoceanopening---anotherclosing,cf.TheCaledonianWilsoncycleortheIndianoceanopening--easternTethyanclosing.Supercontinentcyclisity?FromRodiniatoPangeaandafuturesupercontinent??Doestheearth´scontinentallithospheri

5、cplatesassembleandriftapartinlongertermcycles?http://www.geodynamics.no/platemotions/500-400/BALTICAaseparatecontinent≈550-425Ma500Ma460Ma440Ma420Ma400MaCaledonianorogeniccycleinbrief460Ma440MaNoticethattraditionalWilson-cycletectonicsdoesnotworktoexplainformationoftheCaledon

6、idesAWilsoncycleproducesgeo-tectonicrockunitscharacteristicofthevariousstagesofthecycle.Continentalrift(riftsedimentsandmagmaticproducts)2)Volcanicornon-volcanicpassivemargins(riftmarginwiththinnedcontinentalcrustandassociatedsedimentaryandvolcanicproducts3)Oceancontinenttran

7、sitionalcrust(highlystretchedcrustanddykeintrudedcrust)4)Oceaniccrustw/exoticelements(continentalcrustfragments,oceanislandshot-spots,transformcomplexesetc.)Intra-oceanicconvergentmargins(subductioncomplexes,island-arcsandback-arccomplexesetc)6)Ophiolite/islandarcobduction7)A

8、ndeanmargins(compositebatholiths)Continent-continentcollisionSomeimp