Geology lesson 6

burial metamorphism

a type of metamorphism that occurs when rocks are deeply buried

confining pressure

equal pressure on all sides

contact metamorphism

a type of metamorphism that occurs when rock is exposed to high temperature and low pressure

directed stress

unequal balance of forces on a rock in one or more directions

foliation

minerals lined up in planes

gneiss

a metamorphic rock having minerals separated into light and dark bands

gneissic banding

a metamorphic foliation in which visible silicate minerals separate into dark and light bands

hornfels

a non-foliated dense, fine-grained, hard, rock composed of several silicate minerals

hydrothermal metamorphism

a type of metamorphism in which fluids play a major role

lineation

linear minerals lined up in a rock

marble

a non-foliated metamorphic rock formed from limestone

metamorphic rock

rock formed as starting rock changes into another rock due to exposure to temperature, pressure, and/or fluids

migmatite

a metamorphic rock with some melt and formation of igneous rock

non-foliated

a metamorphic texture showing no preferred orientation

phyllite

a foliated metamorphic rock in which platy minerals have grown larger and the surface of the foliation shows a sheen from light reflecting

protolith

rock exposed to temperature, pressure, and/or fluids that changes into a metamorphic rock

quartzite

a non-foliated metamorphic rock formed from quartz sandstone

regional metamorphism

a type of metamorphism that occurs when parent rock is subjected to increased temperature and pressure over a large area

schist

a foliated metamorphic rock having large platy grains visible as individual crystals

schistosity

a textural description of foliation created by the parallel alignment of platy visible grains

slate

fine-grained foliated metamorphic rock that breaks into flat sheets

slaty cleavage

the flat orientation of the small platy crystals forming perpendicular to the direction of stress

stress

force applied