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Earth science exam 2


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Alfred Wegener
A scienctist who was also trained in astronomy and geophysics and was a professor of geophysics and meteorology
name of the single landmass that broke apart 225 million years ago and gave rise to today's continents.
supercontinent in the Southern Hemisphere, which included South America, Africa, peninsular India, Australia, and Antarctica
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
Evidence for continental drift
match of continental drift
Continuity of Mountain Belts
Geological Formations
Fossils of the Upper Paleozoic fern,
Glascial Deposits & Paleoclimate(occur in southern hemisphere)
Why was he theory of the continental drift rejcted?
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
layers of the Earth
Crust, Lithosphere, Mantle, Inner Core, Outer Core
outer skin and very thin. 25-70 miles thick
uppermost part of the mantle. oceanic and continental crust
thickest layer
Inner Core
behaves like a solid due to the increased pressure
Outer Core
liquid which generates the Earth's magnetic field
Evidence for Plate Techtonics
Paleomagnetism, seafloor spreading, patterns of earthquakes and valcanoes, hot spots
lithosphereic plates
Euraisian Plate, Pacific Plate, Antartic Plate, North American Plate, South American Plate, African Plate, Caribbean Plate, Indo-Australian Plate
Plate Boundaries
Divergent, convergent (oceanic oceanic, oceanic continental, continental continental) Transform
moving apart-rifts- valcanoes (not explosive)
coming together
oceanic oceanic
islands are valcanoes (explosive)
Ocanic continental
mountains/valcanoes (explosive)
continental continental
mountains, stacking (earthquakes)
downwellign of the earth's lithosphere
a valcano is a weak spot in the crust where magma, comes to the surface
where are valcanoes found
aroudn the ring of fire
why does magma rise?
rises because liquid magma is less dense than the surrounding solid material, gasses dissolved in magma rush out
what determines if a valcano will erupt?
viscosity, gas content, and temperature, silica content
parts of a valcano
crater, lava, pipe, vent, magma chamber, magma, side vents,
3 stages of a valcano
active, dormat, extint
one that is erupting or has shown signs that it may erupt in the near future
one which is expected to become active in the future
volcano has typically not erupted for thousands of years and is unlikely to erupt again
sheild valcanoes
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
cinder cone
ash cinders and bombs build up and pile around the vent in a steep cone-shaped hill
composite valcano
tall cone shaped mountains in which layers of lava flows alternate with explosive eruptions of ash, cinder, and bombs
what is an earthquake
the vibration of earth produced by the rapid release of energy
poitn beneath earths surface where rick breaks under stress and causes an earthquake
the point on earths surface directly above and earthquakes focus
what are earthquakes associated with?
earthquakes are associated with faults
p waves
push and pull waves, they can travel through all mediums, they arrive first
s waves
right angle waves, they can only travel through solids, they arrive second
surface waves
up and down and side to side motion, produce most damnage and arrive last
what is a tsunami
waves produced by the tidal effect of the moon or the sun

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