Evidence of Plate Tectonics

Plate Tectonics

The theory explaining the arrangement of continents and the mechanisms behind geologic phenomena like earthquakes, volcanic activity, and mountain building.

Pangaea

The supercontinent that included all of Earth's landmasses, which has since broken apart.

Continental Drift

The movement of continents away from their original positions within Pangaea.

Lithosphere

The rigid outer part of the Earth, consisting of the crust and upper mantle.

Asthenosphere

The slowly flowing part of the upper mantle on which tectonic plates float.

Convergent Plate Boundaries

Regions where two tectonic plates move toward one another, often creating mountains or subduction zones.

Subduction Zone

A boundary where an oceanic plate moves beneath a continental plate, leading to deep ocean trenches and volcanic activity.

Mid-Ocean Ridge

An underwater mountain range formed by the upwelling of magma at divergent plate boundaries.

Rift Valley

A long valley formed when a continental plate is stretched and thinned at divergent boundaries.

Continental Rift

A rift valley that occurs on land when parts of a continental plate pull away from each other.

Transform Plate Boundaries

Locations where two tectonic plates slide past each other without significant vertical movement.

Seafloor Spreading

The process of the Earth's crust moving away from mid-ocean ridges, leading to the formation of new oceanic crust.

Volcano Formation

The process by which magma from the Earth's interior rises to the surface and erupts, forming a volcano.

Earthquake

A sudden release of energy in the Earth's crust resulting from the movement of rocks along faults.

Faults

Cracks in rock bodies along which movement has occurred.

Ring of Fire

A major area in the Pacific Ocean where many earthquakes and volcanic eruptions occur, associated with tectonic plate boundaries.

Fracture Zones

Cracks or faults on the ocean floor that offset mid-ocean ridges horizontally.

Fossil Distribution

The geographic distribution of fossils that provides evidence for the movement of continents over time.

Continental Volcanic Arc

A chain of volcanoes formed on a continental plate at a subduction zone.

Volcanic Island Arcs

Chains of volcanic islands formed where one oceanic plate subducts beneath another.

Folded Mountain Ranges

Landforms created by the collision of continental plates, causing the crust to buckle and rise.

Convection Currents

Circulating flows of molten rock in the Earth's mantle that drive the movement of tectonic plates.

Oceanic Crust

The portion of Earth's crust that underlies the ocean, which is thinner and denser than continental crust.

Continental Crust

The portion of Earth's crust that forms the continents, thicker and less dense than oceanic crust.

Geologic Phenomena

Natural events or processes on Earth such as earthquakes, volcanic activity, and mountain formation.

Mid-Atlantic Ridge

An example of a divergent boundary where tectonic plates are pulling away from each other, resulting in seafloor spreading.