Lithosphere and Plate Tectonics Lecture

20 vocabulary flashcards summarizing essential terms related to Earth's lithosphere and plate tectonics.

Lithosphere

The rigid outer layer of Earth composed of the crust and the uppermost mantle, broken into tectonic plates.

Continental Crust

Thick, buoyant part of Earth's crust primarily composed of granitic rocks that forms the continents.

Oceanic Crust

Thin, dense part of Earth’s crust made mostly of basalt that underlies the ocean basins.

Tectonic Plate

A large, mobile slab of lithosphere that moves over the asthenosphere and interacts at its edges.

Asthenosphere

The semi-molten, ductile region of the upper mantle beneath the lithosphere on which plates slide.

Plate Tectonics

The scientific theory explaining the movement, interaction, and recycling of Earth’s lithospheric plates.

Continental Lithosphere

Portion of the lithosphere that includes continental crust and the attached upper mantle.

Oceanic Lithosphere

Portion of the lithosphere that includes oceanic crust plus its underlying upper mantle.

Plate Boundary

The zone where two tectonic plates meet and interact, often producing geologic activity.

Divergent Boundary

A plate boundary where two plates move apart, creating new lithosphere through magma upwelling.

Convergent Boundary

A plate boundary where two plates collide, leading to subduction or continental mountain building.

Transform Boundary

A plate boundary where two plates slide horizontally past one another, causing earthquakes.

Subduction Zone

Region where an oceanic plate descends beneath another plate into the mantle, generating volcanism.

Mid-Ocean Ridge

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

Rift Valley

A linear depression formed on land at a divergent boundary where the lithosphere is being pulled apart.

Seafloor Spreading

The process by which new oceanic crust forms at mid-ocean ridges and moves outward on either side.

Mantle Convection

Heat-driven circulation in the mantle that acts as the primary mechanism for plate motion.

Continental Drift

Alfred Wegener’s early 20th-century hypothesis that continents move across Earth’s surface.

Hot Spot

A fixed area of intense volcanic activity thought to be caused by a mantle plume beneath a moving plate.

Deep-Sea Trench

A long, narrow depression on the ocean floor marking the surface expression of a subduction zone.