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22 Cards in this Set
- Front
- Back
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Core |
Dense rock, containing rock, iron & nickel Solid inner, molten outer Temperature produced by PRIMORDIAL (left from Earth's formation) & RADIOGENIC (radioactive decay of isotopes) |
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Mantle |
Molten & semi-moloten rocks containing lighter elements (silicon & oxygen) |
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Crust |
Lighter elements, silicon, oxygen, aluminium, potassium and sodium Beneath ocean: 6-10km Below continents: 30-40km Under mountains: 70-?km |
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New plate theory |
suggests crust & mantle divided into LITHOSPHERE ASTHENOSPHERE |
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Lithosphere |
crust & rigid upper section of mantle approx 80-90km Divided into: 7 plates, number of smaller ones |
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Different Plates |
Oceanic: 6-10km, over 1,500m years old, 2.6 density, granite, silicon, oxygen & aluminium Continental: 30-50km, less than 200m years old, 3.0 density, basalt, silicon, oxygen & magnesium |
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Plate Tectonic Theory |
maps of Atlantic produced, topography fit, Wegener published theory that single continent existed called Pangaea, then split into 2 continents, further splitting formed today's continents, CONTINENTAL DRIFT THEORY |
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Geography Evidence |
fit of continenets late-carboniferous glaciation rock sequences in Northen Scotland agree with Easter Canada |
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Biological Evidence |
fossils found in Indian limestone comparable with fossils in Australia fossil remains of reptiles in South America & Southern Africa fossiled remains of plants existed when coal formed located in India & Antarctica |
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Wegener's theory |
theory had little ground: once evidence collected was proven as correct Examination of crust: floor spreading Alternating polarity in rocks Reverses at regular intervals Magnetic strips where rocks aligned alternately towards north and south poles Suggests slowly SPREADING, older with distance EARTH GETTING BIGGER |
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Destruction |
being destroyed to accomodate increase in size, huge OCEANIC trenches |
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Subduction |
sideways and downwards movement of the edge of a plate, pulled downwards |
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Convection currents |
Hot sports around core, generate c.currents Magma rises towards crust Spread before cooling and sinking Crustal plates move on Continuous process, new crust formed at constructive boundaries Destroyed at destructive |
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Oceanic ridges |
Formed when plates move apart in oceanic areas Filled with balsatic lava upwelling to form ridge volcanic activity occurs along ridge Forms SUBMARINE VOLCANOES (rise above sea) |
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RIFT VALLEYS |
plates move apart in continental areas move apart, crust drops between faults area between parallel rift valleys--> horst |
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DEEP SEA TRENCHES |
oceanic and continental meet, denser forced underneath downwarping causes deep ocean trenches similar when two move together |
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ISAND ARCS |
subduction, melts further down, begins to rise causing plutons of magma, reach surface in complex, explosive volcanoes, if underneath ocean known as island arcs |
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YOUNG FOLD MOUNTAINS |
not much subduction when meet forming CONTINENTAL CRUST edges and sediments between forced up= fold mountains material forced downwards, moutain roots sediments accumulated, uplifted as buckle during subduction of O.plate |
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Gravitational sliding |
result of gravity acting down on slope of ridge, force that acts away from ridge, shallow earthquakes shows frictional resistance= sliding |
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Slab pull |
downward gravitational forces sinks into mantle pulls oceanic plate down , negative buoyancy: SLAB PULL |
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Vulcancity |
gases and molten rock extruded and intruded from Earth's crust |
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Seismicity |
occurrence or frequency of earthquakes in a specific region |
