ERTH 2415 Lecture Notes - Lecture 22: Landform, Plinian Eruption, Exothermic Process
14 Dec 2015
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Document Summary
Crust: the earth"s crust is thin, low-density and rich in silicon and oxygen: silicon and oxygen account for ~ 75% of the crust. Mineral: naturally occurring inorganic solid with an orderly internal structure and individual characteristics. Rock: solid aggregate of one or more minerals. Silicon-oxygen tetrahedron molecules form rings, chains, sheets. Rock cycle: describers processes by which older rocks are made and 3d structures into new rocks: theoretical concept predating plate tectonics. Magma: partially molten rock below the earth"s surface: lava: magma that reaches the surface (wash in latin, Volatiles: gasses dissolved in the melt part of the 3 components: components of magma melt (liquid), solids (crystallized (ointment in greek) torrent in ital) of magma minerals) Viscosity: internal resistance of a liquid to flow: most important property controlling magma behaviour (therefore eruptive style) low viscosity = peaceful eruption for example. Types of eruptions have to do with viscosity basalt (low %sio2 and viscosity), andesite (moderate of both), rhyolite (severe)
