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25 Cards in this Set
- Front
- Back
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What are Mountains
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Areas that rise significantly above the surrounding landscape.
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What is Orogeny?
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The period of mountain building.
1. Compressional folding and thrusting 2. Igneous Activity 3. Metamorphism |
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What happens at an Oceanic Oceanic plate boundary?
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Older denser oceanic plate subducts
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What forms at an Oceanic Oceanic plate boundary?
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Volcanic island arc
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What happen when partial melting of the mantle occurs at an Oceanic Oceanic plate boundary?
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1. Mantle has low density and rises.
2. Andesitic lava and pyroclastics |
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What kind of rocks can be produced when mountains are formed in an Oceanic Oceanic plate boundary?
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Igneous & Metamorphic rocks
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Aleutian Islands and Tonga Islands are examples of what?
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Volcanic Island Arcs
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On Continental - Oceanic plate boundaries what forms on a continent?
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Continental Volcanic Arc
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On the Continental - Oceanic plate boundary where does the melting occur?
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Melting occurs along the subduction zone
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What type of magma/lava are there at a Continental - Oceanic plate boundary?
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Andesitic to Granitic
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Thick continental crust slows ascent of magma producing...
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massive plutons (igneous intrusions)
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What type of continental margin has thick wedges of sedimentary rocks?
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passive continental margin
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Passive margins eventually become what?
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Active Continental Margins
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How did the South America become an Active Continental Margin?
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The sudduction with the Nazca plate.
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Andean Type Margins have a...
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Subduction Zone and Continental Volcanic Arc
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What is formed of material (oceanic crust and deep sea sediments) scraped off the subducting plate?
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Accretionary Wedge
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What is an example of an eroded continental volcanic arc?
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Sierra Nevada of California
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The Franciscan sediments of the COast Ranges (of California) are composed of what material?
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Accretionary Wedge
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Continental Continental Collisions form what type of mountains?
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Folded Mountains
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What is the result with Continental Continental Collisions?
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Folding, thrusting, emplacement of plutons (igneous intrusions) and metamorphism.
*Crust is shortened and thickened |
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Examples of Folded Mountians?
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Himalayas
Appalachians |
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How did the Himalayas form?
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India began colliding with Eurasia 40 million years ago.
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How did the Appalachians form?
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The collision of North America, Europe & Africa.
*Final orogeny 250-300 million years ago. |
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What has lowered the Appalachians?
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Subsequent erosion
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What is the origin of the extension of continents?
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Mantle upwelling and intrusion, accompanied by volcanism, domes, and extension of the crust.
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