GEOS 1004 Lecture Notes - Lecture 8: Convergent Boundary, Biotite, Rock Cycle
Document Summary
Blueschists near san francisco indicate that subductions was once active here. Metamorphic rocks are produced when existing rocks are changed (cooked essentially) by changes in heat, pressure, and/or fluids. All metamorphic processes occur in the solid state. Understanding the results of metamorphism is key to learning an area"s tectonic history and thus how to best interact with/live in that area i. Under blacksburg is sedimentary rock, but not buried deep enough to be metamorphic rock. Metamorphism- a solid state process which changes the texture, mineralogy, and sometimes the chemical composition of a rock a. b. Basalt + heat, pressure, and water = greenschist. Presence of water = chemical changes ii. iii. Limestone (calcium carbonate) + heat, pressure = marble. Size of the crystal or grains that we see in a rock. In general, metamorphic changes increase crystal size c. Certain elements (or compounds like water) may be added or removed.
