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Unit 07 24-25
Plate Tectonics
Term | Definition |
---|---|
Continental drift theory | the hypothesis that the Earth’s continents were once one large landmass and have moved over geologic time relative to each other |
Convergent boundaries | plate boundaries where the plates are moving toward each other |
Divergent boundaries | plate boundaries where the plates are moving apart |
Fossils | mineral replacements, preserved remains, or traces of organisms that lived in the past |
Plate tectonics | Earth's surface is broken into large pieces called plates that are constantly moving and changing at a very slow rate |
Superposition (law of) | each rock layer is older than the one above it |
Transform boundaries | plate boundaries where the plates are moving past each other in different directions |
Alfred Wegener | primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered as the originator of continental drift hypothesis by suggesting in 1912 that the continents are slowly drifting around the Earth |
Asthenosphere | a portion of the Earth's mantle that flows like molten plastic despite being solid. |
Continental plate | one of the large pieces of the surface of the earth that move separately. |
Convection | process by which heat is transferred by movement of a heated fluid such as air, water, or magma. |
Dense | the measurement of how tightly a material is packed together. |
Earthquakes | the sudden release of strain energy in the Earth's crust, resulting in waves of shaking that radiate outwards from the earthquake source. |
Harry Hess | an American geologist and a United States Navy officer in World War II who is considered one of the "founding fathers" of the unifying theory of plate tectonics. |
Hot spots | a large plume of hot mantle material rising from deep within the Earth. A line of volcanoes develops as a plate moves over a hotspot. |
Index fossils | the remains of plants and animals that have existed only for a limited geologic period. |
Lithosphere | includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth's structure. |
Magnetic striping | a pattern of magnetic fields in strips of rock as they radiate outward from an ocean ridge. |
Mountains (fault block) | formed by the movement of large crustal blocks when forces in the Earth's crust pull it apart. |
Mountains (folded) | created where two or more of Earth's tectonic plates are pushed together. At these colliding, compressing boundaries, rocks and debris are warped and folded into rocky outcrops, hills, mountains, and entire mountain ranges. |
Ocean basin | any of several vast submarine regions that collectively cover nearly three-quarters of Earth's surface. |
Oceanic plate | plates that are located beneath the ocean. |
Pangaea | was a supercontinent formed during the late Paleozoic era that existed until the late Triassic era approximately 280 - 230 million years ago |
Ring of Fire | a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes. |
Sea floor spreading | a geologic process in which tectonic plates—large slabs of Earth's lithosphere—split apart from each other. |
Subduction zone | where Earth's tectonic plates dive back into the mantle, at rates of a few to several centimeters per year. |
Supervolcanoe | a volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index (VEI), meaning that at one point in time it erupted more than 1,000 cubic kilometers (240 cubic miles) of material. |
Volcanoes | openings, or vents where lava, tephra (small rocks), and steam erupt onto the Earth's surface. |