GL101 Lecture Notes - Lecture 22: Metamorphic Rock, Silly Putty, Metamorphism
Document Summary
When a rock is subjected to t or p very different from where they formed. Not melting, crystallizing, changing because of temperature. Texture and specific mineral makeup depend on particular physical processes in the metamorphic transformation. Only in extreme cases of fluid migration do metamorphic rocks change in composition form their parent rocks. Heating: from intrusive igneous bodies, from earth"s internal heat different times. Different minerals are stable at different temperature, so change occurs at. Applies forces equally in all directions harder and denser metamorphic rocks. ^ sort of like play dough or silly putty. Unequal pressure in different directions results in distortion. Directed pressure layered or banded texture: foliation. Foliation: preferred orientation of platy and elongate minerals in a metamorphic rock; oriented parallel to direction of minimum stress. At depth, higher temperature and higher pressure cause minerals to dehydrate. Ions expelled with water and travel to other sites in crystal structure: recrystallization.
