Metamorphic Rocks and Plate Tectonics Vocabulary

Metamorphic Rock

rock formed from the alteration of pre-existing rock under the influence of heat and pressure

Contact Metamorphism

metamorphism due to contact with or proximity to an igneous intrusion

Regional Metamorphism

morphism that occurs over broad areas of the crust

Foliated

metamorphic rocks that have layers and banding

Non-foliated

metamorphic rocks that do not have layers and banding

Rock Deformation

the action or process of changing in shape or distorting, especially through the application of pressure

Rock Stress

a force acting on a rock per unit area; compression, tension, and shear

Rock Strain

a change in shape or size resulting from applied forces

Anticline

a ridge-shaped fold of stratified rock in which the strata slope DOWNWARD from the crest (like an arch)

Syncline

a trough or fold of stratified rock in which the strata slope UPWARD from the axis (like a U)

Earthquake

a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth’s crust or volcanic action

Earthquake Fault

a fracture along which the blocks of crust on either side have moved relative to one another parallel to the fracture

Earthquake Focus

the place inside Earth’s crust where an earthquake originates

Epicenter

the point on the earth’s surface vertically above the focus of an earthquake

Seismic Waves

an elastic wave in the earth produced by an earthquake or other means

Primary (P) Wave

first seismic wave to leave the focus, it forces the ground to move backwards and forwards

Secondary (S) Wave

second seismic wave to leave the focus; it forces the ground to move up and down

Surface Wave

a seismic wave that travels along or parallel to the earth’s surface; most destructive

Tsunami

a long high sea wave caused by an earthquake, submarine landslide, or other disturbance

Earth’s Crust

the outermost shell of a terrestrial planet

Earth’s Mantle

the mostly-solid bulk of Earth’s interior; convection happens here

Outer Core

the third layer of the Earth; liquid

Inner Core

solid material found in the center of some planets at extremely high temperature and pressure

Continental Drift

the gradual movement of the continents across the earth’s surface through geological time

Pangaea

a supercontinent that incorporated almost all the landmasses on Earth

Plate Tectonics

a theory explaining the structure of the earth’s crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle

Divergent Boundary

boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth’s surface between the two plates

Convergent Boundary

a boundary where two plates come together; impact of the colliding plates can cause the edges of one or both plates to buckle up into a mountain ranges

Subduction Boundary

a boundary in which one edge of one crustal plate is forced below the edge of another; can form deep ocean trenches

Transform Boundary

boundary where two of the Earth’s tectonic plates touch and slide alongside one another