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18 Cards in this Set
- Front
- Back
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What is the Icelandic Ridge?
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The portion of the Mid-Atlantic Ridge that runs through Iceland. Iceland is on the boundary of the North American Plate and the Eurasian Plate
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What is the East African Rift?
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An active continental rift zone in eastern Africa developing at a divergent plate boundary
Contains a triple junction - the African plate is splitting into two new tectonic plates |
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Where are converging boundaries found most in the world?
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Ring of Fire
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What are hotspots?
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An area of persistent volcanic activity.
Originate at unusually hot areas of the mantle-core boundary |
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What is the Hawaiian hotspot?
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A volcanic hotspot responsible for the creation of the Hawaiian Islands
The chain of islands extends from Hawaii to the eastern edge of Russia |
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What are the three classifications of lava-forming rocks?
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Basalt, Andesite, Rhyloite
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What are the characteristics of basaltic lava?
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highest density
lowest viscosity highest tendency to form lava lowest tendency to form pyroclastics typical minerals include feldspar, pyroxene, olivine, horneblende |
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What are the characteristics of andesitic lava?
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intermediate density
intermediate viscosity intermediate tendency to form lava intermediate tendency to form pyroclastics typical minerals include feldspar, horneblende, pyroxene, micas |
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What are the characteristics of rhyolitic lava?
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least density
highest viscosity least tendency to form lava highest tendency to form pyroclastics typical minerals include feldspar, quartz, mica, horneblende |
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What is Pahoehoe and a'a'?
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Types of lava flow
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What is pahoehoe lava flow?
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Basaltic lava that has a smooth surface - due to the movement of very fluid lava under a congealing surface crust
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What is a'a' lava flow?
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Basaltic lava characterized by a rough surface composed of broken lava blocks
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What are pyroclastics?
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Fragmented material that sprayed out of a volcano and landed on the ground or sea floor in solid form
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What are some different types of pyroclastics?
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Ash
Lapilli Bombs (largest) |
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What is pyroclastic flow?
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a fast-moving current of superheated gas and rock (ash) from a volcanic eruption
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What are ignimbrites?
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Rock formed when deposits of pyroclastic flows solidify
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What are lahars?
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A type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water
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What are calderas?
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A large circular depression with steep walls and a fairly flat floor, formed after an eruption as the center of the volcano collapses into the drained magma chamber below
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