英语翻译
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Thehardplatesthatformthesurfacepartoftheearthareabout100kilometersthick.Theseplatesincludeboththeearth'scurstandtherppermantle.
Togetherthecrustanduppermantleformthesurfaceplatesoftheearth.Thishardplatefloatsonthedensermaterialofthelowermantlethewayapieceofwoodfloatsonapond.Theplatesarecarriedalongbyslowflowsbeneaththem.
Withanunderstandingofplateformation,scientistshaveputforwardanewtheoryfortheearth'ssurface.About200millionyearsago,theplatesattheearh'ssurfaceformedasuper-continent.Whenthissuper-continentstartedtotearapartbecauseofplatemovement,itfirstbrokeintotwolargecontinentalmasses,withanewlyformedseathatgrewbetweenthelandareas.ThesouthernoneincludedthemoderncontinentsofSouthAmerica,Africa,Australia,andAntarctica.ThenorthernonewasmadeupofNorthAmerica,Europe,andAsia.NorthAmericatoreawayfromEuropeabout180millionyearsago,formingtheNorthernAtlanticOcean.
Theplatemovementisresponsibleforearthquakes,volcanoesandtheearth'slargestmountainranges.Forexample,theedgeofthePacificOceanhadbeencalled"RingofFire"becausesomanybolcaniceruptionsandearthquakeshappenthere.Beforethe1960's,scientistscouldnotexplainwhyactivevolcanoesandstrongearthquakeswereconcentratedinthatarea.Thetheoryofplateformationgavethemananswer