GEOL 105 Chapter : GEOLOGY CH5 8
15 Mar 2019
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Erupted 79ad, buried pompeii in ash, ruins remain. Ash piles up & when settles back down to ground, still warm/compact, creates a solid layer of rock. Citizens suffocated/buried in ash/bodies decaied and left ash casts explosivity , oceanic(hawaii) 1)volcanoes a)volcanism: geologic (study of) process involved in eruptions b)mt. vesuvius: naples, italy c)volcanic landforms d)materials extruded during eruption. Relationship to explosivity: lower the pressure, bigger the bubbles. Explosiveness controlled by:amount of gas/how easily gas can escape* a)mafic lava: low viscosity, hot,gasses escape easily, lava flow, low silica, low b)felsic lava: high viscosity, colder, pressure builds up,explosive(st. helens) Columnar jointing: cracks formed when cooling form colom like textured rocks. Pillow lava: lava erupts on seafloor, comes into contact with water and top layer cools instantly, lava seeps through skin over & over, forms blob/worms. Caldera: large bowl shaped depression,material blasts out here. Occurs when magma chamber empties, top/summit collapses down onto chamber. 1-shield volcano: (looks like a normal volcano but short and not steep)
