Earth Sciences 1022A/B Lecture Notes - Lecture 7: Metamorphic Rock, Clay Minerals, Hornfels
21 Nov 2018
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Document Summary
Metamorphic rock = changed-form rock: occurs in the presence of heat and pressure. There are different textures that occur: contact metamorphism (only heat, placing something cool next to a heat source, occurs to uniform pressure, regional metamorphism (heat and pressure, uneven pressure (usually through tectonic activity) and heat. Definition: pre-existing rock is heated (i. e. baked ) under uniform pressure: produces a new rock over time. Rock produced: minerals in the product are in a random orientation may be confused as an igneous rock, there is no pressure direction applied so the minerals are oriented randomly (no visible grains) Example: shale (sedimentary) hornfels (metamorphic: andelusite = new mineral containing silica and other materials, begins as the ingredients in shale and clay (ex. Silica, aluminum: these minerals will re-arrange themselves to become new minerals that are. More stable at a higher temperature: same basic ingredients that are slightly changed.
