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21 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is plate tectonics?
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The theory that pieces of Earth's lithosphere move slowly on top of the asthenosphere.
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The theory that...
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What does the theory of plate tectonics explain?
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The formation and movement of Earth's plates.
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The formation and movement of...
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What did Alfred Wegener do?
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He hypothesized that the continents were once joined in a single supercontinent, which then moved into pieces that moved apart (Pangaea).
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He hypothesized that...
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What is continental drift?
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A process in which continents move slowly on the Earth's surface.
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A process in which...
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What is a mid-ocean ridge?
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A chain of underwater mountains.
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A chain of...
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What did Harry Hess do?
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He proposed the idea of sea-floor spreading.
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He proposed...
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What happens as pieces of ocean floor move apart?
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Magma from the mantle wells up and solidifies to form new oceanic crust.
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Magma from the mantle...
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What is subduction?
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A process in which old oceanic plates sink into the mantle.
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A process in which...
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What happens during subduction?
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Gravity slowly pulls the dense edges of oceanic plates into the mantle, destroying old ocean floor.
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Gravity slowly pulls...
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What is a trench?
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A depression in the ocean floor that forms when a plate bends as it sinks through a subduction zone.
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A depression in...
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What did geologists find about underwater rocks?
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Rocks near the mid-ocean ridge were younger and those farther away were older.
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Rocks near the mid-ocean ridge...
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What does sea-floor spreading do?
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It creates new oceanic crust at mid-ocean ridges. Sunduction destroyes old oceanic crust at subduction zones.
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It creates new...
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What force moves the plates?
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Convection currents form in the mantle as hot rock rises at mid-ocean ridges, cools and spreads horizontally as ocean lithosphere, and then sinks back into the mantle at subduction zones.
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Convection currents...
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At what rates do plates move?
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Very slowly (about 10 to 0.1 cm per year)
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Very...
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How do plate motions relate do mantle convections?
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They are the visible part of it.
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They are...
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What are the types of plate boundaries?
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Divergent boundaries, convergent boundaries, and transform boundaries.
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DCT
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What is a divergent boundary?
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Where plates move away from each other
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Where plates...
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What is a convergent boundary?
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Where plates come together or collide.
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Where plates...
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What is a transform boundary?
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Where plates slide past each other, moving in oppositre directions.
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Where plates...
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Where do most mountains form?
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Along plate boundaries.
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Along...
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How do mountains form?
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As plates collide, the crust buckles, folds, and thickens, pushing up mountains.An oceanic plate collides with a continental plate. Two plates diverge and magma wells up and solidifies as mountains (mid-ocean ridge).
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3 things
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