7.10A Changes in Earth Over Time Flashcards

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climate

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The general weather of a particular area over a long period of time

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continental drift theory

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The theory that states Earth's continents were once joined together as one supercontinent, called Pangaea, and have since drifted apart to their present-day locations

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convection currents

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The circular flows of material, generally liquids or gases, caused by temperature differences

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fossil evidence

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The preserved remains of extinct organisms that provide geological records of past events

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mid-ocean ridge

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An underwater mountain belt formed by seafloor spreading where rising magma creates new crust

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Pangaea

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The huge landmass or supercontinent Earth's seven continents once formed about 250 million years ago

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plate tectonic theory

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The theory that states Earth's surface is broken into large slabs of rock, whose movements cause the formation of various landforms as well as phenomena such as volcanic eruptions and earthquakes; also known as plate tectonics

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seafloor spreading

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The separation of two oceanic plates that results in the formation of new oceanic crust at mid-ocean ridges

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supercontinent

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A giant landmass composed of most or all of Earth's land

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superposition

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A geologic principle stating that as undisturbed rock layers form, younger rock layers sit on top of older rock layers