GL101 Chapter Notes - Chapter 7: Metamorphic Rock, Metamorphism, Parent Rock
Document Summary
It does not melt or it would become igneous rock upon cooling: the degree to which a parent rock is changed depends on the degree of the processes involved. Controlling factors in metamorphism: composition of parent rock. While some volatiles may migrate in or out during metamorphism, the chemical composition of a metamorphic rock usually resembles its parent rock. Minerals may recrystallize into different minerals but bulk composition (prevalence of various elements; si, fe, mg, ca) remains similar: heat (most important) Heat can occur from intrusive igneous bodies and earth"s internal heat. Influences the mobility and reactivity of chemically active fluid. Different minerals are stable at different temperature, so change occurs at different times: pressure. Results in harder and denser metamorphic rocks. Results in distortion of a parent rock body. Rocks are brittle at the surface and fracture when subjected to directed pressure. Rocks are ductile at depth, and can flatten and elongate, depending on conditions.
