Plate Boundaries - Vocabulary

Vocabulary flashcards covering plate boundaries concepts from the notes.

Plate boundary

The border between two tectonic plates where deformation of the lithosphere occurs.

Divergent boundary

A boundary where two plates move apart, often creating seafloor spreading and features like mid-ocean ridges and rift valleys.

Convergent boundary

A boundary where two plates move toward each other; three types exist: oceanic-continental, oceanic-oceanic, and continental-continental.

Transform boundary

A boundary where two plates slide horizontally past one another, causing earthquakes along faults (e.g., San Andreas Fault).

Mid-ocean ridge

An undersea mountain range formed by upwelling magma at divergent boundaries, where seafloor spreading occurs.

Rift valley

A linear valley formed in continental crust as it stretches and pulls apart at divergent boundaries.

Fissure

A long crack in the lithosphere through which magma can erupt at divergent boundaries.

Subduction zone

A region where a denser plate sinks beneath a less dense plate at a convergent boundary.

Trench

A deep underwater trough formed where subduction occurs.

Volcanic arc

A chain of volcanoes formed on the overriding plate above a subduction zone.

Island arc

A chain of volcanic islands formed when an oceanic plate subducts beneath another oceanic plate.

Oceanic crust

Thinner, more dense crust that forms the ocean floor.

Continental crust

Thicker, less dense crust that forms the continents.

Oceanic lithosphere

Rigid outer shell of the Earth that includes oceanic crust and the upper mantle.

Continental lithosphere

Rigid outer shell of the Earth that includes continental crust and the upper mantle.

Asthenosphere

The partially molten, weak layer beneath the lithosphere that allows plate movement.

Oceanic-Continental convergence

A convergent boundary where an oceanic plate sinks beneath a continental plate (subduction), forming a trench and volcanic arc.

Oceanic-Oceanic convergence

A convergent boundary where one oceanic plate subducts beneath another, forming a trench and often an island arc.

Continental-Continental convergence

A convergent boundary where two continental plates collide, creating tall mountain ranges and collision zones.

San Andreas Fault

A transform boundary between the Pacific and North American plates known for horizontal movement and earthquakes.

Seafloor spreading

The creation of new oceanic crust as magma rises at divergent boundaries and pushes plates apart.

Earthquakes

Ground shaking caused by movement along faults at plate boundaries.

Mountain ranges

Long, high landforms formed by continental-continental convergence (collisions).