ENVIRSC 1G03 Lecture Notes - Lecture 16: Metamorphic Rock, Overburden Pressure, Amphibolite

• School: McMaster University
• Department: Environmental Science
• Course: ENVIRSC 1G03
• Professor: Maureen Padden

Document Summary

Metamorphic rocks are created through metamorphism; they have been changed mineralogically and/or texturally through heat, pressure, or fluids: but without the rock melting in the process, they provide a window into past temperatures, pressures, and fluid composition. Unlike igneous and sedimentary processes, we can"t see metamorphic rocks forming naturally. Instead, we: use deduction based on texture on mineralogy, recreate conditions in the lab. Prevalent in the most deformed parts of mountain ranges. Two common types: contact metamorphism: metamorphism in which high temperature is the dominant factor. Occurs relatively close to the earth"s surface (cid:697)within (cid:736)(cid:735)km(cid:698); therefore confining pressure is usually quite low. Subjected to confining pressure equal in all directions. Can occur surrounding a pluton when the body of magma intrudes into relatively cool surrounding rock (cid:710)baking(cid:711) of country rock adjacent to an intrusive contact. Usually only affects areas 1m 100m around the intrusion.