Origin of Ocean Basins and Plate Tectonics

These flashcards cover key vocabulary and concepts related to the origin of ocean basins and plate tectonics.

Ocean Basin

A large portion of the ocean floor that lies deeper than 2,000 meters below sea level.

Exotic Terrane

A rock body that is bound by faults and unrelated to rock bodies adjacent to it.

Hot Spots

Fixed plumes of rising lava that originate in the mantle, found within ocean basins.

Lithosphere

The coherent rigid outer shell of the earth that includes both the crust and upper mantle.

Lithospheric Plate

A portion of the lithosphere bounded by various types of boundaries: transform faults, spreading centers, and subduction zones.

Magma

Molten rock material within the earth; magma that reaches the surface is called lava.

Spreading Center

A mid-ocean rise or ridge where molten material rises to create new sea floor.

Subduction Zone

An elongate region where a crustal plate descends below another.

Transform Fault

A lateral-slip fault along which the displacement suddenly stops.

Seafloor Spreading

The process by which new oceanic crust is created at mid-ocean ridges as magma rises up.

Paleomagnetism

The study of the record of Earth's magnetic field in rocks, sediment, or archeological materials.

Wilson Cycle

The sequence of events leading to the formation, expansion, contraction, and eventual elimination of ocean basins.

Benioff Zone

An area of increasingly deeper seismic activity that runs parallel to a subduction trench.

Continental Drift

The hypothesis that continents have moved across the Earth's surface over geological time.

Andesite Lava

Lava with a composition intermediate between granite and basalt, typically found at subduction zones.

Normal Fault

A fault along which the crustal rocks are displaced vertically relative to each other.

Magnetic Anomalies

Variations in magnetic field strength detected in rocks, reflecting seafloor spreading and magnetic history.

Lithospheric Plates

Large segments of the lithosphere that move and interact at plate boundaries.

Seismicity

The frequency, magnitude, and distribution of earthquakes.

Tectonism

The deformation of Earth's crust caused by tectonic forces.