Presentation on theme: "Metamorphic Rocks. Rock Cycle Objectives 14 – Describe the types of changes associated with metamorphic rocks. 15 – Contrast regional and contact metamorphism."— Presentation transcript:
Objectives 14 – Describe the types of changes associated with metamorphic rocks. 15 – Contrast regional and contact metamorphism.
Metamorphic Rocks Pre-existing rocks changed by heat and pressure
Different Types of Changes Compaction Grains move closer. Rock becomes more dense. Porosity reduced. Example: clay to shale to slate Recrystallization- Growth of new crystals. No changes in overall chemistry. New crystals grow from the minerals already present Foliation Minerals separate into bands New minerals form from heat and pressure
Types of Metamorphism: Contact Contact (thermal) Small scale Associated with igneous intrusions
Types: Regional Metamorphism Regional (dynamic) Large scale Associated with mountain building
Foliated vs. Non-foliated Foliated – has bands or layers Non-foliated - No banding Form from rocks made up of single minerals
Rank The degree of metamorphism required to change a rock