Plate Tectonics

Continental Drift

The theory that continents have moved away from each other over time.

Plate Tectonics

The scientific theory explaining the movement of the Earth's lithosphere.

Types of Plate Boundaries

Divergent, convergent, and transform boundaries.

Driving Force of Plate Motion

Plates that are driven by mantle convection, slab pull, and ridge push.

Alfred Wegener

The scientist who proposed the theory of continental drift and provided evidence such as fossil distribution and geological similarities.

Paleomagnetism

The study of the magnetic properties of rocks to determine the history of the Earth's magnetic field.

Paleomagnetism and Continental Drift

Paleomagnetism provides evidence for continental drift by showing how Earth's magnetic poles have changed positions over time.

Two Types of Ocean Crust

Continental crust and oceanic crust; oceanic crust is denser and thinner than continental crust.

Subduction

The process where one tectonic plate moves under another and sinks into the mantle.

Seafloor Spreading

The process by which new oceanic crust is formed at mid-ocean ridges and slowly pushes older crust away.

Slab Pull

A force exerted by the weight of a subducting plate that pulls the rest of the plate along with it.

Dividing the Layers of Earth

The two common methods are by physical properties (lithosphere and asthenosphere) and by chemical composition (crust, mantle, core).

Mid-Ocean Ridges

Underwater mountain ranges formed by plate tectonics, where seafloor spreading occurs.

Active Margins

Coastal regions that are tectonically active, often featuring earthquakes and volcanic activity.

Passive Margins

Coastal areas that are not tectonically active, typically characterized by wide continental shelves.

Wadati-Benioff Zones

Zones of earthquakes occurring at subduction zones that indicate the presence of an oceanic plate descending into the mantle.

Hot Spots

Volcanically active areas that are not at plate boundaries, caused by upwelling of hot mantle material.

Triple Junctions

Points where three tectonic plates meet, commonly associated with significant geological activity.

Trenches

Deep valleys in the ocean floor formed at convergent plate boundaries, where one plate is subducting beneath another.

Transform Faults

Faults that form where two tectonic plates slide past one another horizontally.