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30 Cards in this Set
- Front
- Back
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Igneous rock
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any rock that comes from the cooling of a molten state
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Sedimentry rocks
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rocks that come from pre-existing fragment or made by chemical activity.
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Metamorphic rocks
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rocks buried deep in the earth and can changed by heat and pressure by not melting
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What are almost all rocks made of?
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silicate+metals
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Wht makes lava thicker?
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more silica
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What makes volcanos explode?
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when thick lava traps gases and ...BOOM!!!
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Basalt - low silica content
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; runny lava allows gases to peacefully escape
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Andesite/Ryolite - high silica contaent
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thick lava traps gases causing an explosion
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- Shield volcanos
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made of basalt; not explosive but are huge; lava runs out and spreads so they are wider than they are tall
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Composite Volcano aka strato-volcano
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high silicate; layers of ash and thick lava. Shape is more pointy and sides are steep. Explosive!!!
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How many layers is the earth's surface made of?
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two
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Waht is the longest maontain range system in the world?
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Mid-ocean Ridge System
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What must you understand in order to undersand Plate Tectonics?
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The layers of the earth
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How many layers does the earth's crust haev and what are the?
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Two; Continental crust and Oceanic Crust
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What are the specs of the oceanic crust?
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Thinner of the two (4 mi apprx; variable); heavy in weight and darker in color; made of basalt; because they are heavy theyare lower in elevation
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What are the specs of the Continental crust?
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thicker of the two (20 mi apprx; variable); light in clr&wght; made of high silica rock; lighter so it stays afloat
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The Theory of Plate Tectonics
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- lithosphere moves over the asthenosphere
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What is the layer of earth called that is under the crust?
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Mantle
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What are the layers of the mantle?
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lithosphere and athenosphere
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Which is the upper layer of the mantle and what is it broken into?
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lithosphere; broken into plates (continents)
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What is the lithospshere composed of?
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really dense silica rock
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What is the lower level of the mantle?
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athenosphere
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What's the athenosphere's compostion?
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Thin weak partly melted zone; mostly solid but like a hot slush
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What is the MOHO?
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The area between the lithoshere and the athenosphere; top of the athenosphere
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What drives pate tectonics?
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earth's internal temp; convection
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What is pangea?
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When all the continents are connected
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When was the last Pangea?
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300,000 million years ago
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When was the last ice age?
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20,000 years ago but it was not the first one
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How do we know that ice once covered a certain part of the earth?
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it leaves a certain sediment or scratches that no other element leaves
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What is the evidence of plate tectonics?
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-Continents fit togather
-rocks fit -fossils match back up -mountains line up -earthquakes concentrate at plates -magnetometry strngst evdenc; some areas rocks are pointed south and others north |
