EESA06H3 Lecture Notes - Lecture 5: Salar People, Andes, Atacama Desert
9 Apr 2014
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Document Summary
When oceans close is the dangerous volcanoes because of subduction. Iceland is very fluid not that dangerous, all gases come out. More viscosious - dangerous, stuff comes out pyroclastic. Pyroclastic broken by fire, rocks are shattered by eruptions and thrown up into air. Volcanic bombs or ash(is a misnomer - named improperly: italy thought it was coal burning. The green areas subduction back into the mantle. The pacific ring of fire: tectonics of a closing ocean. Pacific rim - dense concentration of volcanes, major earthquakes, tsunamis subduction viscosiy of. The stars marks earthquakes - the deepest earthquakes are 700km down. We know that slabs don"t melt till after 700km down. Magmatic arc a line of volcanoes directly above. Oceanic crust made out of basalt. Silicic magma - sediment + seawater melted, reducing. Deep water trenches ocean floor going down into subduction zone. New zealand: small island, exposed tip of a much larger land mass (zealandia)
