Presentation on theme: "EARTH MATERIALS EQ:What are metamorphic rocks? A rock that has changed its mineral assemblage and texture from a pre- exiting one due to increases in temperature."— Presentation transcript:
EARTH MATERIALS EQ:What are metamorphic rocks? A rock that has changed its mineral assemblage and texture from a pre- exiting one due to increases in temperature and pressure. Metamorphic Rocks CLASSROOM UNSQUARED
Metamorphic Rocks Temperature Depth of burial (Avg. geothermal gradient = C / km) Proximity to magma Pressure (Stress) A. Overburden (Avg. geopressure gradient = 33 MPa / km) B. Lateral Compression Foliation Metamorphism causes Recrystallization Foliation (mineral bands) Chemical change Metamorphic grade Old bedding planes A. B.
Metamorphic Rocks and Parent Rocks Parent Rock Sandstone Shale Limestone Granite Diorite Slate Phyllite Schist (Identification Key)Identification Key Quartzite Slate Marble Gneiss Phyllite Schist Gneiss Metamorphic Rock
Two Kinds of Metamorphism Regional metamorphism Compression in convergent plate boundary Covers large area in a region along a plate boundary Contact metamorphism Local effect along the margin of a magma intrusion Location of valuable mineral ores