Plate Tectonics – Key Vocabulary

30 vocabulary flashcards covering the essential terms and concepts from the lecture on plate tectonics.

Plate Tectonics (Theory)

Scientific theory stating that Earth’s lithosphere is divided into moving tectonic plates whose interactions shape the planet’s surface.

Tectonic Plate

A rigid slab of lithosphere that moves slowly over the asthenosphere.

Lithosphere

The rigid outer layer of Earth, consisting of the crust and uppermost mantle.

Asthenosphere

The semi-plastic, slowly flowing layer of the upper mantle on which tectonic plates move.

Convection Currents

Circular flow of heated, less-dense mantle material rising and cooler, denser material sinking, driving plate motion.

Mantle Convection

Heat transfer process in the mantle that acts like a conveyor belt, moving tectonic plates.

Ridge Push

Plate-motion force produced when cooling, denser lithosphere slides down an elevated mid-ocean ridge.

Slab Pull

Force generated as a dense, sinking lithospheric plate edge drags the rest of the plate into a subduction zone.

Plate Boundary

The border where two tectonic plates meet and interact.

Divergent Boundary

Plate boundary where two plates move apart, forming mid-ocean ridges or rift valleys.

Convergent Boundary

Plate boundary where two plates collide or one subducts beneath another, forming trenches, mountains, or volcanoes.

Transform Boundary

Plate boundary where two plates slide past one another horizontally; often marked by faults and earthquakes.

Subduction Zone

Region where one tectonic plate descends beneath another into the mantle.

Mid-Ocean Ridge

Underwater mountain chain formed at divergent boundaries where new oceanic crust is created.

Rift Valley

Long, narrow depression formed when continental plates diverge.

Sea-Floor Spreading

Process of new oceanic crust forming at mid-ocean ridges and moving outward.

Trench

Deep, narrow depression in the ocean floor created at a subduction boundary.

Island Arc

Curved chain of volcanic islands formed above a subducting oceanic plate.

Hot Spot

Fixed area of exceptionally hot mantle where magma rises to create volcanoes, often forming island chains.

Volcano

Opening in Earth’s crust that erupts gases, ash, and lava; commonly occurs at divergent and convergent boundaries or hot spots.

Magma

Molten rock located beneath Earth’s surface.

Lava

Molten rock that has reached Earth’s surface during a volcanic eruption.

Fault

Fracture in Earth’s crust where rocks have slipped past each other.

Normal Fault

Fault caused by tension where the hanging wall moves down relative to the footwall.

Reverse (Thrust) Fault

Fault produced by compression where the hanging wall moves up relative to the footwall.

Strike-Slip Fault

Fault where two blocks slide horizontally past each other; characteristic of transform boundaries.

Earthquake

Vibration of Earth’s crust produced by sudden release of energy along faults or boundaries.

Tsunami

Large sea wave generated mainly by underwater earthquakes, landslides, or volcanic eruptions.

Folded Mountains

Mountain ranges formed by compression and crustal folding at convergent boundaries, e.g., the Himalayas.

Ring of Fire

Seismically active zone of volcanoes and earthquakes encircling the Pacific Ocean.