01:460:100 Lecture Notes - Lecture 8: Metamorphic Rock, Clay Minerals, Protolith

• School: Rutgers University
• Department: Geological Sciences
• Course: 01:460:100
• Professor: Mark Feigenson

Document Summary

Chapter 8 - metamorphism: a process of change. Metamorphism - metamorphic rock forms from a pre-existing rock or protolith. During metamorphism, new minerals grow at the expense of old minerals, and/or the shape, size, and arrangement of grains in the rock may change. Changes occur in the solid state because melting doesn"t occur. Changes induced by heat, pressure, differential stress, and/or hydrothermal fluids. Metamorphic texture: minerals have grown in situ and interlock. Recrystallization: changes the shape and size of a mineral grain without changing the mineral. Metamorphic minerals: distinct minerals that only grow under metamorphism (may have a metamorphic mineral assemblage). Old minerals (reactants) decompose to form new ones (products). Metamorphic foliation: defined by the parallel alignment of platy minerals and/or the presence of light and dark colored bands. Protoliths - undergo changes in texture and mineralogy. These changes are due to variations in temperature, pressure, tectonic stress, and the amount of reactive water.