Earth Sciences 1022A/B Lecture Notes - Schist, Mica, Amphibole
Document Summary
Earth sciences 1022b lecture brief 30 jan 14. Rocks can be deeply buried, intruded by magma, or squeezed; they are subjected to heat, pressure, and chemically active fluids: these agents result in metamorphism. Increases mainly with temp. , as indicated by index minerals in metamorphic rocks: (low grade) chlorite, muscovite, biotite, garnet, staurolite, sillimanite (high grade) Contact metamorphism: caused by magma intrusion into cooler parent rocks. Results in metamorphic aureoles with decreasing effect away from the intrusion. Host rock minerals recrystallize to new minerals but are not reoriented (nonfoliated) e. g. marble from baking limestone, quartzite from baking sandstone, because calcite and quartz do not recrystallize into platy or elongate minerals.