GEO 101 Lecture Notes - Lecture 10: Parent Rock, Phyllite, Gneiss
22 Feb 2017
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Exam #1 will cover up through today (i. e. , up through metamorphic rocks) A study guide has been posted to blackboard. On monday, february 6th, we will have an in-class review session and dr. hansen will discuss the exam in more detail then, but bring your questions. Formed by increases in temperature and/or pressure from: Causes recrystallization; results in new, stable minerals. Two main sources: heat from nearby magma, geothermal gradient, pressure. Weight of the overlying rocks; increases with depth. Mineral grains become more closely packed and may recrystallize, becoming smaller dense minerals. Pressure that is not equal on all sides; it is directional. Occurs during deformation associated with mountain building: fluids. Enhances migration of ions and promotes recrystallization of existing minerals. Where does the water come from: pore spaces of sedimentary rocks, fractures in igneous rocks, hydrated minerals, parent rock. Mineral composition determines the degree to which change will occur.
