GEOL 106 Chapter Notes - Chapter 4: Volcanic Crater, Pyroclastic Flow, Pyroclastic Rock
6 Nov 2018
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Most occur along ring of fire surrounding pacific ocean basin areas outside ring of fire can also experience volcanoes because of hot spot activity (yellowstone) or because they are located on a portion of mid-ocean ridge (iceland) Lava flows lava flow: result when magma reaches surface and overflows central crater or erupts from volcanic vent along flank of volcano. Pahoehoe: lava that has smooth, sometimes ropey surface texture when they harden. Black sand is produced when molten lava enters relatively cold ocean water and shatters into sand sized particles. Pyroclastic deposit: accumulation of tephra that when deposited hot can be fused to form pyroclastic rock. Pyroclastic flow: flows of pyroclastic debris that are hot and race down side of volcano attaining high speeds gases within the flow can reach temperatures of 1000 degrees also known as ash flows, hot avalanches, nuee ardentes.
