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51 Cards in this Set
- Front
- Back
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who proposed "continental drift"; what year
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Alfred Wegener; 1915
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what is the age of Pangaea, the supercontinent
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200 million years
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ocean surrounding Pangaea
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Panthalassa
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sea between Laurasia and Gondwanaland
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Tethys Sea
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how long does it take to recycle rock on the sea floor
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110 million years
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flaw in Wegener's theory of continental drift
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false method for movement
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who proposed convection cells as the source of plate movement; when
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Harry Hess; 1962
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3 sources supporting continental drift
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fossils, continental fit, paleomagnetism
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animals such as sea turtles may use what as a source of navigation
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magnetic field
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axis of a mid-ocean ridge
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spreading center
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average range of speeds of plates today
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2-12 cm/yr
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depressed area of a mid-ocean ridge
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rift valley
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when land rifts, what is a high section of crust called
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horst
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when land rifts, what is a low section of crust called
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graben
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boundary where two plates move apart
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divergent boundary
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boundary where two plates move toward each other
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convergent boundary
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boundary where two plates move parallel to each other in opposite directions
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transform boundary
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where are transform faults found
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mid-ocean ridges
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what 2 general processes can occur from converging plates
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subduction, collision
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sea floor spreading is faster at oceanic rises or ridges?
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oceanic rises
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example of an oceanic rise
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East Pacific Rise
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length of oceanic ridge system
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75,000 km
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old scale for measuring earthquakes' intensities
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Richter scale
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modern scale for measuring earthquakes' intensities
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seismic moment magnitude (M-subscript-w) aka moment magnitude scale
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example of an oceanic ridge
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Mid-Atlantic Ridge
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how much stronger is an Mw=6 earthquake than Mw=5
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30 times as powerful
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what are the 2 primary types of seismic waves
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pressure (longitudinal), shear (transverse)
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what type of seismic wave can't pass through liquids
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shear waves (transverse)
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a string of volcanoes resulting from increased pressure near subduction zones
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volcano arc
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2 types of volcano arcs
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continental arc, island arc
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examples of island arcs
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Aleutian islands, Mariana islands
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average height of oceanic ridges
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2.5 km
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average width of oceanic ridges
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1000 km
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remnant of a transform fault that is no longer active
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fracture zone
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example of a transform fault on land
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San Andreas Fault
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columnar areas of molten rock that arise from deep within the mantle
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mantle plumes
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locations where mantle plumes come to the surface
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hotspots
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approximate number of active hotspots on Earth
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100+
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group of islands resulting from a plate moving over a hotspot
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nematath
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examples of nemataths
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Hawaiian islands, Galapagos islands
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newest volcano in Hawaiian chain still below water surface
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Loihi
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mountain on sea floor that is taller than 1 km but doesn't break surface
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seamount
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seamount that has a flat top due to erosion
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tablemount (guyot)
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stages of coral reef development from earliest to latest
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fringing reef, barrier reef, atoll
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largest reef in the world; how long
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Great Barrier Reef; 2000 km
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study of the historical changes of continental shapes and positions
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paleogeography
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study of changes of the oceans brought about by paleogeographical changes
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paleoceanography
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addition of material (islands, volcanoes) to a continental landmass
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continental accretion
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theory for the motion of lithospheric plates in its modern form
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plate tectonics
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life cycle of ocean basins
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Wilson cycle
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6 stages of Wilson cycle from first to last
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embryonic, juvenile, mature, declining, terminal, suturing
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