ERS120H5 Study Guide - Midterm Guide: Divergent Boundary, Subduction, Oceanic Crust
Document Summary
Metamorphosis is about change, changing from one state to another. Change in form, by applying heat and pressure. Deformation: compression or shear; not all rocks are deformed. Composition: what you start with dictates what you end with. Time: takes a long for it to become a metamorphic rock. Recrystalization: same composition, same minerals; crystals are either bigger or smaller. Phase change: same composition, new mineral; ex. Neocrystalization: new composition, new minerals; most common process. Same mineral, but different size or shape. Solid state meaning there is no melting. Example: sandstone becomes larger in crystal size and forms new grains (quartz) after metamorphism. Example: mineral is calcite; protolith (limestone) and the new mineral has calcite in it. Protolith (clay minerals) and after metamorphism, the mineral now contains quartz, garnet and mica. As these minerals grow and are deformed by pressure, they align. Shearing allows one part of the mineral to move sideways relative to another.
