GEO 303 Chapter Notes - Chapter 3: Endmember, Augite, Orthoclase
24 Dec 2017
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Document Summary
Igneous rocks form by crystallization (or solidification) of melted material. Magma is a combination of melted silicate material, volatiles, and some solidified igneous rock. At the earth"s surface , lava, cools to form volcanic, or crystals. Generalization about magma behavior and sequence of crystallization. Minerals crystallizing along the discontinuous series have different structures of. Quartz is a framework silicate in which every tetrahedron is linked at its corners. Tetrahedrons. to four other tetrahedrons (every oxygen atom is shared). than minerals lower in the series. Minerals that crystallize first, at higher temperatures, have higher melting points. Complexity of silicate structures increases down the series. Viscosity of the magma increases down the series. Minerals lower in the series are more resistant to chemical weathering. Mafic: iron (fe) and magnesium (mg) rich, high melting temperature, low viscosity, low volatile content, mild volcanic eruptions, dark-colored minerals in mafic rock (ex: augite, hornblende, ca-plagioclase)
