2BellworkAlfred Wegener could not explain what caused the continents to move. It is now believed that _____ currents inside Earth cause plates to move.Bands or stripes of basaltic rock on the seafloor showing alternating magnetic orientation indicate Earth's magnetic field has _____ in the past.While studying the ocean floor, scientists found _____ of magnetism.As you get farther from a mid-ocean ridge, sea floor rocks become _____.Answer BankconvectionMid-ocean ridgesolderstripesreversed
3BellworkAnswer BankolderOcean ridgesContinentalFossilsseafloor(see figure above) As you get farther from a mid-ocean ridge, sea floor rocks become ______.Alfred Wegner noticed that the _____, rocks, and mountains matched up across continentsMid-_____ _______ are a continuous chain of volcanoes that extends through many of the earth’s oceans where new crust of the Earth is created.The two theories that lead up to plate tectonics are ______ drift and ______ spreading.
4Bellwork 1. Earth’s magnetic field protects us from the ____ ______ 2. When magma cools at mid-ocean ridges, a mineral called magnetite ______ itself with the earth’s magnetic field.3. Harry Hess noticed ______ on the seafloor.4. Each magnetic ________on the seafloor showed a _______in the earth’s magnetic field.5. These magnetic stripes were strong evidence for seafloor ________ and plate tectonics.Answer BankReversalReversedspreadingStripe(2)youngerSolar windaligns
5Continental (use twice) BellworkEast Africa and Mid-ocean ridges are two examples of a _______ plate boundary.A _______ zone is the area where the plate sinks back into earth melting as it descends.The two types of crust are ________ and _______ crust.An island arc like Japan formed by a collision of ocean crust colliding with _____ crust at a convergent plate boundary.The Himalayan Mountains formed from the collision of continental crust colliding with _________ crust.6) Draw& Label:Answer BankSubductionContinental (use twice)Ocean (use twice)DivergentRift ValleyConvergent BoundaryDivergent BoundarySubduction Zone
6BellworkA _______ is located at location A where plates collide and ocean plate subducts .2) New rock or plate is created at ______ boundaries and plate is destroyed at _________ boundaries.3) At location B, ocean plate is _____ as it subducts and sinks4) The subduction of oceanic plate beneath continental plate produces ____ _____Answer BankVolcanic mountainsTrenchconvergentDivergentMelting