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Geography vocabulary: Difference between revisions
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* formed when magma from below breaks through the earth's crust | * formed when magma from below breaks through the earth's crust | ||
** lava, ash, and gasses escape | ** when that happens, lava, ash, and gasses escape from the earth's hot mantle | ||
** as lava accumulates, volcanic mountains, below and above the | ** as lava accumulates and hardens, volcanic mountains, below and above the seas form | ||
* two principle of volcanos: | |||
** conical volcano | |||
*** the most common type of volcano with high walls and a cone at the top | |||
*** built up by layers (or "strata") of lava and other airborne, solid "fragments" of ash and cinders | |||
*** in a conical volcano the lava flow hardens before spreading far | |||
**** stratovolcano (or composite volcano from layers of lava flows), spatter cone (from a lava fountain) | |||
**** see also cinder, rootless, and tuff cones: Volcanic cone - Wikipedia | |||
** shield volcanos | |||
*** the lava flows outward and the volcano does not build up like a conical volcano | |||
* there are various types of volcanic eruptions | |||
* the earth's crust itself is originally built of lava | * the earth's crust itself is originally built of lava | ||
** = "igneous rock" | ** = "igneous rock" | ||