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67 Cards in this Set
- Front
- Back
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Group of lithospheric rock moving in the same direction |
plates |
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tectonic plates = |
crust+ upper mantle |
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do edges of plates correspond with continents always? |
no |
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What kind of crust and core does Earth have? |
large core, thin crust |
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how do plates move? |
convection in the mantle; cold lithosphere sinks, hot lithosphere rises |
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arc shaped depression with steep sides at the bottom of the ocean. Coincides with subduction zone |
trenches |
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How is plate movement tracked? |
GPS |
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How much do plates move per year? |
1-15 cm |
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Divergent boundaries create: |
oceanic ridges |
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convergent boundaries create: |
subduction zones and trenches |
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What kind of boundaries do NOT produce volcanoes? |
continent/continent convergent and transform |
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where is the subduction zone in an ocean/continent convergent boundary? |
ocean |
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What is formed at a divergent continental boundary? |
rift valleys and mountains |
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What is formed at ocean/ocean convergent |
island arc trench |
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what is formed at ocean/continent convergent? |
continental arc trench |
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what is formed at oceanic divergent |
mid ocean ridge |
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what is formed at a transform boundary? |
parallel ridges and valleys |
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where is the age of oceanic crust youngest? |
near the ridges |
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What can produce melting of rocks? |
increased temperature, decreased pressure, reactions from adding water |
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When do divergent plate boundaries occur? |
rising mantle rock causes plates to move apart |
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modern divergent oceanic |
Mid atlantic ridge |
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modern divergent continental |
east african fault |
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modern ocean convergent |
Japan Aleutian Islands |
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Modern ocean/continent convergent |
Andes Cascades |
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modern continent convergent |
Himalaya |
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modern transform |
San Andreas |
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What are formed from the solidification of magma and pyroclastic material? |
igneous rocks |
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What kind of boundaries can igneous rocks be found on? |
convergent and divergent |
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pressures relationship with melting: |
higher pressure, higher melting |
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Water content relationship with melting: |
higher water content, lower melting point |
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composition relationship with melting: |
higher silica, lower melting point |
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What are mafic rocks? |
low silica, high melting temp |
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what are felsic rocks? |
high silica, low melting temp |
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changes in pressure allowing the rocks to melt and rise to the surface |
decompressional melting |
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What are intrusive igneous rocks? |
formed inside the earth |
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what are extrusive igneous rocks? |
formed outside the earth |
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Why do rocks melt in convergent boundaries? |
they have water induced melting |
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Where is new oceanic lithosphere created? |
divergent plate boundaries |
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where is new oceanic lithosphere released |
convergent plate boundaries |
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granite |
coarse grain felsic |
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rhyolite |
fine grained felsic |
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diorite |
coarse grained intermediate |
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andesite |
fine grained intermediate |
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gabbro |
coarse grained mafic |
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basalt |
fine grained mafic |
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peridotite |
coarse grained ultra mafic |
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what are fast cooling extrusive rocks |
fine grained |
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what are slow cooling intrusive rocks |
coarse grained |
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Vent in the surface of the earth where magma gasses and ash erupt |
volcano
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Types of volcanoes from smallest to largest
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scorcia cone
dome small shield composite shield |
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what are volcanic hazards
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pyroclstic material, lava flows, volcanic gasses
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what are volcanic gasses composed of
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50-60% water vapor
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Mt st helens
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high silica, felsic, strato-composite, highly viscous
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What controls how quickly the lava moves?
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viscosity
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high viscosity is..
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high resistance to flow
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low viscosity is..
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free flowing, more liquid
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What affects viscosity?
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temperature and content
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What temperatures result in more viscous?
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lower temperature
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what silica content is more viscous?
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more felsic - more viscous
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What speeds the movement of lava to the surface?
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bubbles
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what has the least amount of bubbles?
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more viscous
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what kind of explosion does a high viscous lava cause?
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explosive
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What volcano has more of a peak
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composite
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What kind of lava is in a composite volcano?
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felsic, highly viscous
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what kind of lava is in a shield volcano?
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mafic, low viscosity
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What volcano has multiple layers of ash?
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strato/composite
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what kind of magma do the Hawiian islands have?
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low silica
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