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42 Cards in this Set
- Front
- Back
Alfred Wegener
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A scienctist who was also trained in astronomy and geophysics and was a professor of geophysics and meteorology
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Pangaea
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name of the single landmass that broke apart 225 million years ago and gave rise to today's continents.
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Gondwanaland
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supercontinent in the Southern Hemisphere, which included South America, Africa, peninsular India, Australia, and Antarctica
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Lauraisa
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supercontinent that broke off from the Pangaean supercontinent in the late Mesozoic era. It included most of the landmasses which make up today's continents of the northern hemisphere
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Evidence for continental drift
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match of continental drift
Continuity of Mountain Belts Geological Formations Fossils of the Upper Paleozoic fern, Glascial Deposits & Paleoclimate(occur in southern hemisphere) |
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Why was he theory of the continental drift rejcted?
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continent fit wasnt perfect, correlation of rock units was weak, tillites werent glacial deposits, northern hemisphere colas werent tropical.
wegener wasnt a geologist so his credicility was attacked No mechanism |
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layers of the Earth
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Crust, Lithosphere, Mantle, Inner Core, Outer Core
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Crust
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outer skin and very thin. 25-70 miles thick
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Lithosphere
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uppermost part of the mantle. oceanic and continental crust
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Mantle
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thickest layer
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Inner Core
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behaves like a solid due to the increased pressure
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Outer Core
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liquid which generates the Earth's magnetic field
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Evidence for Plate Techtonics
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Paleomagnetism, seafloor spreading, patterns of earthquakes and valcanoes, hot spots
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lithosphereic plates
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Euraisian Plate, Pacific Plate, Antartic Plate, North American Plate, South American Plate, African Plate, Caribbean Plate, Indo-Australian Plate
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Plate Boundaries
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Divergent, convergent (oceanic oceanic, oceanic continental, continental continental) Transform
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Divergent
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moving apart-rifts- valcanoes (not explosive)
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Convergent
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coming together
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oceanic oceanic
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islands are valcanoes (explosive)
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Ocanic continental
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mountains/valcanoes (explosive)
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continental continental
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mountains, stacking (earthquakes)
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transform
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earthquakes
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subduction
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downwellign of the earth's lithosphere
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valcano
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a valcano is a weak spot in the crust where magma, comes to the surface
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where are valcanoes found
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aroudn the ring of fire
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why does magma rise?
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rises because liquid magma is less dense than the surrounding solid material, gasses dissolved in magma rush out
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what determines if a valcano will erupt?
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viscosity, gas content, and temperature, silica content
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parts of a valcano
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crater, lava, pipe, vent, magma chamber, magma, side vents,
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3 stages of a valcano
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active, dormat, extint
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active
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one that is erupting or has shown signs that it may erupt in the near future
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dormat
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one which is expected to become active in the future
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extinct
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volcano has typically not erupted for thousands of years and is unlikely to erupt again
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sheild valcanoes
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layers of lava pour out of the vent and harden on top of previous layers, lave flows gradually build up a wide, gently sloping mountain
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cinder cone
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ash cinders and bombs build up and pile around the vent in a steep cone-shaped hill
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composite valcano
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tall cone shaped mountains in which layers of lava flows alternate with explosive eruptions of ash, cinder, and bombs
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what is an earthquake
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the vibration of earth produced by the rapid release of energy
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focus
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poitn beneath earths surface where rick breaks under stress and causes an earthquake
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epicenter
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the point on earths surface directly above and earthquakes focus
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what are earthquakes associated with?
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earthquakes are associated with faults
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p waves
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push and pull waves, they can travel through all mediums, they arrive first
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s waves
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right angle waves, they can only travel through solids, they arrive second
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surface waves
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up and down and side to side motion, produce most damnage and arrive last
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what is a tsunami
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waves produced by the tidal effect of the moon or the sun
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