EESC Tectonic plates

Lithosphere

The rigid outer layer of the Earth, broken into plates.

Asthenosphere

The semi-fluid layer beneath the lithosphere on which tectonic plates move.

Plate Boundaries

The edges where two tectonic plates meet, where geologic activity is concentrated.

Divergent Boundary

A tectonic plate boundary where two plates move away from each other.

Convergent Boundary

A plate boundary where two plates collide.

Transform Boundary

A boundary where two tectonic plates slide past each other.

Active Continental Margins

Regions associated with active tectonic boundaries, experiencing geologic activity.

Passive Margins

Regions not associated with active tectonic boundaries, with features like wide continental shelves.

Subduction Zones

Convergent plate boundaries where one plate sinks beneath another into the mantle.

Oceanic vs. Continental Collision

In a collision, the oceanic plate subducts because it is denser than continental crust.

Continental Collision Zones

Areas where two continental plates collide, resulting in mountain formation without subduction.

Sea Floor Spreading

The process by which new oceanic crust is formed at mid-ocean ridges.

Mid-Ocean Ridges (MOR)

Underwater mountain ranges formed at divergent boundaries.

Continental Rifting

The process where continental lithosphere stretches and thins, forming rifting basins.

Oceanic Transform Faults

Transform boundaries found between segments of mid-ocean ridges.

Continental Transform Boundaries

Transform boundaries that cut through continental crust.

Trenches

Deep underwater features formed at subduction zones where oceanic crust bends and sinks.

Volcanic Arcs

Chains of volcanoes formed at convergent boundaries, can be continental or oceanic.

Abyssal Plain

A flat, deep part of the ocean floor, formed by the accumulation of sediments.