GEOL 104 Study Guide - Midterm Guide: Igneous Textures, Silicate Minerals, Peridotite
6 Feb 2018
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Distributing prohibited | downloaded by scarlet choi (choia980806@gmail. com) lomoar cpsd| 1578061. Rare composition that is composed entirely of ferromagnesian silicates. Silica (sio2) content in crustal rocks exhibits a considerable range - a low of 40% in ultramafic rocks. Used to described the overall appearance of an igneous rocks based on the size, shape, and crystal arrangement of interlocking crystal. Tells us about the environment in which the rock was formed. Three factors affecting crystal size: rate of cooling. Slow rate promotes the growth of fewer, but larger, crystals fast rate forms many small crystals. Very fast rate forms glass (unordered ions: amount of silica (sio2) present, amount of volatiles (dissolved glass)
