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Geography vocabulary: Difference between revisions
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=== volcano === | === volcano === | ||
* formed when magma from below breaks through the earth's crust | |||
** lava, ash, and gasses escape | |||
** as lava accumulates, volcanic mountains, below and above the sea form | |||
* the earth's crust itself is originally built of lava | |||
** = "igneous rock" | |||
*** "igeneous" is from ''ignis'', Latin for "fire" | |||
*** other rock types: | |||
**** sedimentary = layered minerals and organic material | |||
**** metamorphic = new rock types formed by pressure and heat of existing rocks | |||
* breaks in the earth's crust are caused by [[File:World Distribution of Mid-Oceanic Ridges.gif|thumb|World distribution of mid-oceanic ridges]] | |||
** shifts in and colliding of tectonic plates | |||
** thus places where the plates are either separating for converging, such as: | |||
*** separating = mid-oceanic ridges, which surround several of the continents, including: | |||
**** Mid-Atlantic ridge from Greenland to southern Atlantic, in the center of the Atlantic Ocean | |||
**** Pacific ridges, which extend from Baha California south and east, below Australia and connecting with the mid-Oceanic ridges of the Indian Ocean | |||
*** converging (crashing into one another), such as: | |||
**** the "Ring of Fire" | |||
** weakening or thinning of the crust, such as: | |||
*** East African Rift | |||
*** Wells Gray-Clearwater volcanic field in British Columbia, Canada | |||
*** Rio Grande Rift: from below the Colorado Plateau to the northern border of Mexico, covering most of New Mexico and parts of Arizona | |||
**** note: the eastern edge of the Rio Grande Rift forms the North-South vertical portion of the New Mexico-Texas natural border | |||
* Sources: | * Sources: | ||
* [[https://www.nationalgeographic.org/encyclopedia/landform/ Landform (National Geographic)]] | * [[https://www.nationalgeographic.org/encyclopedia/landform/ Landform (National Geographic)]] | ||