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Earth Theories
Continental Drift, Sea Floor Spreading, Plate Tectonics
Question | Answer |
---|---|
Alfred Wegener | A German scientist who generated the theory of continental driftin 1910 |
Pangea | The name of the single landmass that broke apart 300 million years ago and gave rise to today's continents |
Continental Drift | The hypothesis that states that the continents slowly move across Earth's surface |
Evidence from Mountain Ranges | Wegener noticed that a mountain range in South Africa lined up with a mountain range in Argentina |
Evidence from Fossils | Fossils of reptiles Mesosaurus and Lystrosaurus have been found in places now seperated by ocean |
Evidence from Climate | There have been tropical plant fossils found on the island of Spitsburgen which has a harsh polar climate |
Glossopteris | A fernlike plant that lived 250 million years ago |
Deep Sea Vent | Black smokers in the ocean |
Mid-Ocean Ridge | The undersea mountain chain where new ocean floor is produced; a divergent plate boundary |
Sonar | A device that determines the distance of an object under water by recording echoes of sound waves |
Iceland | An island that is part of the mid-ocean ridge that rises above the surface in the North Atlantic Ocean |
Harry Hess | He proposed the idea that the ocean floors move like conveyor belts, and carry the continents with them |
Sea-Floor Spreading | The process that continually adds new material to the ocean floor |
Evidence from Pillow Magma | This evidence showed that molten material has erupted again and again from cracks along the central valley of the mid-ocean ridge |
Evidence from Magnetic Stripes | This evidence shows that new seafloor is being made |
Evidence from Drilling Samples | This evidence shows that newer rock is closer to the mid-ocean ride and the older rock is near the continents |
Deep Ocean Trenches | A deep valley along the ocean floor through which oceanic crust slowley sinks towards the mantle |
Subduction | The process by which oceanic crust sinks beneath a ddeep-ocean trench and back into the mantle at a convergent plate boundary |