ERTH 2415 Lecture 9: ERTH 2415_ Lecture 9
8 Feb 2019
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Document Summary
Volcano eruptions get their source of energy from the earth"s internal energy. To understand the magma characteristics that control peaceful versus explosive volcanic eruptions. To understand the relation between tectonic environments, magma composition and eruptive style. To be able to give examples of volcanoes from each tectonic environment. Due to planetary differentiation: 8 elements form 98% of the earth"s crust. Magma = partially molten rock below the earth"s surface. Solids: minerals crystallized from the melting rock. Volatiles: gases that are dissolved in the melting rock. Crystallization = a process of mineral formation by solid-liquid separation in cooling magma. Igneous rocks = formed by cooling and solidification from hot molten rock material. Intrusive igneous rocks: are cooled at magma depth (cooled deeply) Slow at cooling, creates large crystals, solidify at depth and then are exposed by erosion. Extrusive (volcanic) igneous rocks: cooled at the surface. Fast at cooling, creates small crystals, have contact with the atmosphere.
