Earth Sciences 1022A/B Lecture Notes - Lecture 1: Lava Lamp, Lava, Cinder Cone
Document Summary
1022a: they happen when magma reaches the earth"s surface and extruded violently (viscous) or may gently flow down the volcano, why, build up of gas, viscosity ties into the composition: lots of silicon=more viscous, iron and magnesium=more runny. Materials extruded: lava flows, hotter, runny pahoehoe (ropy) crust solidifies with lava still flowing underneath, cooler, viscous aa (blocky, pillow lavas form under water right off of the island into the ocean, the outer crust forms a crust instantly and looks like a lava lamp and break open again and form things that look like pillows, pyroclastic material ranges from fine ash to large bombs eg. mt edna in italy , nuee ardentes (very hot cloud of ash and gas) large bombs eg. mt edna in italy , nuee ardentes (very hot cloud of ash and gas) eg. mt st. helens 1980; lahars (wet ash flow) happens under a glacier or snow mixed with gas.