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PLATE TECTONICS. Why the Earth is Like It Is. What Did The Earth Look Like In The Past?. Evidence to support Tectonic Theory. Continents coast lines fit together like a jig saw puzzle same fossils found on different continents.
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PLATE TECTONICS Why the Earth is Like It Is
Evidence to support Tectonic Theory • Continents coast lines fit together like a jig saw puzzle • same fossils found on different continents
Plates are “pushed” and “pulled” over the surface of the Earth due to unbalanced forces. Why Do Plates Move? REMEMBER CONVECTION? Convection currents reach the surface, plates are pushed apart. As the plates move away from each other, part of them are pulled into the Earth’s mantle.
THREE TYPES OF MOVEMENT. • CONVERGENT- oceanic and continental plates collide forcing the oceanic plate to slide beneath. • DIVERGENT - plates move away from each other, where they diverge molten rock rises. • TRANSFORM - plates move horizontally past each other.
Convergent Boundaries- Three Types Continent/Continent Ocean/Continent Ocean/Ocean
Resulting landforms from Convergence – Moving Together Trenches Structural Mountains Volcanoes
Divergent Plate boundary Sea Floor Spreading forms ridges as the sea floor spreads apart and lava rises Rift Valley forms if the land is above water
TRANSFORM BOUNDARY • Transform boundaries occur in a few places to accommodate lateral, or side to side motion, in which plates slide past one another.
As two continental plates move toward each other, what landforms would you expect to see? • Volcanoes • Cliffs • Mesas • Structural Mountains
As two continental plates move toward each other, what landforms would you expect to see? • Volcanoes Incorrect These form at edges of plates or over hot spots.
As two continental plates move toward each other, what landforms would you expect to see? • Cliffs Incorrect These are erosional landforms or minor uplift areas.
As two continental plates move toward each other, what landforms would you expect to see? • Mesas Incorrect These are erosional landforms in a desert.
As two continental plates move toward each other, what landforms would you expect to see? • Structural Mountains – correct - Two continental masses will push into each other and “crumple” the edges to form mountains.
Where would you find the newest land on Earth? • In areas of continental convergence • In areas where two ocean plates come together • In areas where plates are moving apart • In areas where two plates are sliding past each other
Where would you find the newest land on Earth? • In areas of continental convergence Incorrect Structural mountains would form here from existing land.
Where would you find the newest land on Earth? • In areas where two ocean plates come together Incorrect You would find trenches and subduction in this area.
Where would you find the newest land on Earth? • In areas where two plates are sliding past each other Incorrect You would find land movement, but not new land being formed.
Where would you find the newest land on Earth? • In areas where plates are moving apart Correct When plates move apart, it is due to magma reaching the surface. When magma cools, new land is formed.
