APES Unit 4

Continental Crust

Thicker, less dense, and older type of crust.

Oceanic Crust

Thinner, denser, and younger type of crust, primarily made of basalt.

Subduction

The process where the denser oceanic crust sinks beneath the continental crust.

Divergent Boundary

A tectonic boundary where plates move apart, resulting in the formation of new crust.

Convergent Boundary

A tectonic boundary where plates collide, resulting in features like trenches and volcanoes.

Transform Boundary

A tectonic boundary where plates slide past each other, often resulting in earthquakes.

Convection Currents

Movement within the mantle caused by hot magma rising and cool magma sinking, driving tectonic plate motion.

Mid-Ocean Ridge

An underwater mountain chain formed at divergent boundaries where magma rises and creates new crust.

Rift Valley

A lowland region formed where continental crust splits apart at a divergent boundary.

Subduction Zone

A region where one tectonic plate sinks beneath another, often creating trenches and influencing volcanic activity.

Hotspot

A stationary plume of hot magma that creates volcanoes in the middle of tectonic plates.

Island Arc Formation

Chains of volcanic islands formed from oceanic–oceanic subduction processes.

Ocean Trenches Formation

Deep depressions formed when an oceanic plate subducts beneath another plate.

San Andreas Fault

A transform boundary in California known for its earthquake activity.

Mantle Convection Cycle

The cycle involving the heating and cooling of magma in the mantle that drives tectonic plate movements.

Magnetic Striping

Alternating magnetic bands on the ocean floor that provide evidence for seafloor spreading.