Earth Sciences 1022A/B Chapter Notes - Chapter 4: Magma Chamber, Lava, Feldspar
22 Sep 2012
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Gas build-up in magma chamber: carbon dioxide, methane. Eruption releases pressure at critical point and process repeats. Running mafic flow: magnesium and ferrum. More violent felsic flow: feldspar and silica. Hotter, runny pahoehoe (ropy) - picture 1. Cooler, viscout aa (blocky) - picture 2. Pillow lavas form under water - picture. 2: repeatedly breaks through quenched tube ends. Ranges from fine ash to large bombs. Very hot cloud of white ash and gas. Gets mixed up with snow, ice, during rain fall. Mass of molten rock form when a volcano ejects viscous fragments of lava during an eruptios. Shield figure 4: broad dome of lava flows, reminded early hawaiian of warrior shield, thus the name, biggest volcanoes, eg. hawaii. Cinder cone figure 5: small, pyroclastic, eg. Composite cone figure 6: mixed materials, intermediate size, eg. Pour lava onto land to build up lava plateaus: flat sheets of lava lava fountaining occurs. Plate boundaries (most active: *** esp. at convergent boundaries.
