Composition of the EarthEarth LayersThe earth isnt a solid sphereIt is made of 4 major layers-Crust-Mantle-Outer core-Inner coreCrustouter skinContinental crust is about !km thickOceanic crust is about "! km thick#this is $hy so much ocean drillin% occurs&Mantle'bout ()!! km thickMade of mostly Iron* +ilicon and Ma%nesium'sthenosphere is the upper part of the mantle,ery -iscous Outer Core'ppro. ("!! km thickMade of molten Iron and /ickelInner Core'ppro. "0!! km radius+olid ball of Iron and /ickel1.tremely hot+tays a solid due to -ery hi%h pressureQuick checkT23 4 all layers are made of solid rockT23 4 thickest layer is the mantleT23 4 Inner core is made of li5uid Iron and nickelT23 4 Outer core is made of silicon and o.y%enAnswers3 4 all layers are made of solid rockT 4 thickest layer is the mantle3 4 Inner core is made of li5uid Iron and nickel3 4 Outer core is made of silicon and o.y%enPlate MovementCaused by con-ection currents in the mantleDefinitionsTrench 4 steep $alled -alley $here ( plates meet+lab pull 4 plates subductin% pulls the rest of the plate $ith it6id%e 7ush 4 ne$ formin% rock pushes plate a$ay from spreadin% centreDefinitions+preadin% Centre 4 area $here plates mo-e apart from each other6ift ,alley 4 a spreadin% centre that occurs on landTypes of MovementCollisions at Plate oun!aries8i-er%ent-7ullin% apart #spreadin%&-/e$ rock is often formed hereCollisions at Plate oun!ariesCon-er%ent-7lates come to%ether-Often subduction occurs #one slides under the other&99More on this in a moment99Collisions at Plate oun!ariesTransform-7lates slide past each other-7roduces earth5uakes-1%: +an 'ndreas 3aultConver"ent oun!ariesThere are three different types of con-er%ent boundariesThese depend on $hat type of plates come to%etherOceanic-continentalOceanic-oceanicContinental-continentalOceanic#ContinentalThe oceanic plate subducts beneath the continental plate1%: Coastal ;CThe