Plate Boundaries - VOCABULARY Flashcards

Vocabulary flashcards covering key terms related to plate boundaries and plate tectonics from the module.

Plate tectonics

Theory that the Earth's lithosphere is divided into moving plates whose interactions at boundaries cause earthquakes, volcanism, and mountain building; movements are driven by mantle convection.

Lithosphere

The rigid outer shell of the Earth consisting of the crust and the upper mantle.

Plate boundary

The lines where two tectonic plates meet and interact, often producing earthquakes, volcanoes, and crustal deformation.

Divergent boundary

A plate boundary where plates move apart, creating new lithosphere; associated with mid-ocean ridges and continental rift valleys; also called constructive boundary.

Convergent boundary

A plate boundary where plates move toward one another; can involve subduction (oceanic plate sinks beneath another plate) or continental collision forming mountains; also called destructive boundary.

Transform boundary (transform fault)

A plate boundary where plates slide past one another horizontally; examples include strike-slip faults like the San Andreas Fault.

Subduction

The process by which one tectonic plate sinks beneath another and descends into the mantle at a convergent boundary; linked to trenches and volcanic activity.

Mid-ocean ridge

An undersea mountain range formed at divergent boundaries where new oceanic crust is created through seafloor spreading.

Rift valley

A deep valley formed when a continental plate diverges and stretches, often leading to continental break-up.

Oceanic-Continental boundary

A convergent boundary where an oceanic plate subducts beneath a continental plate, producing a volcanic arc on the continental margin and a trench.

Oceanic-Oceanic boundary

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

Continental-Continental boundary

A convergent boundary where two continental plates collide, causing crustal thickening and mountain building (no subduction).

Island arc

A curved chain of volcanic islands formed parallel to a trench at oceanic-oceanic convergence.

Volcanic arc

A chain of volcanoes that forms on a continent or island arc at an oceanic-continental convergence.

Trench

A long, deep depression at subduction zones where one plate sinks beneath another.

Himalayas

Mountain range formed by the collision of two continental plates at a convergent boundary (no subduction).

San Andreas Fault

A famous transform fault boundary in California where the Pacific and North American plates slide past each other.

Convection current

Heat-driven movement of mantle material that propels the motion of tectonic plates.

Oceanic crust

Thin, dense part of Earth's crust that sinks beneath less dense continental crust at subduction zones.

Continental crust

Thicker, less dense part of Earth's crust that lies above oceanic crust and forms continents.

Destructive boundary

Another term for a convergent boundary, where crust is destroyed by subduction.

Constructive boundary

Another term for a divergent boundary, where new lithosphere is created.