ESC2000 Lecture Notes - Lecture 3: Aquifer, Volcanic Glass, Mafic
Document Summary
Cooling history slow cooking, deep underground = large crystal size/intrusive texture rapid cooking ex. a lava flowing on the surface = smaller crystal size/extrusive texture very fast cooling (quenching) = volcanic glass (no crystals)/glassy texture. High silica content (low fe + mg) = felsic (light in color) Lower silica content (high fe + mg) = mafic (dark in color) Int: sedimentary formed from the byproducts of weathering & erosion. Importance: they tell you about the environment they formed in, fossils are preserved in sedimentary rock, economic importance: Ground water // aquifer typically high porosity/permeability sandstone. Oil: metamorphic formed when any other rock type is subjected to elevated temps.
