plate tectonics: Quick Facts

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World map highlighting the major tectonic plates, each shaded in a different color, with labeled names such as Pacific Plate, North American Plate, Eurasian Plate, African Plate, South American Plate, and Indo-Australian Plate. Arrows across the map indicate the direction of movement for each plate.

Cross-sectional diagram of Earth's outer layers, showing oceanic and continental crust at the surface, the rigid lithosphere, the partially melted asthenosphere, and transitions from upper to lower mantle, with labeled depths and rock properties.

Cross-sectional diagram illustrating plate tectonics, showing oceanic and continental crust moving over the asthenosphere. It highlights divergent boundaries at oceanic ridges where crust forms, convergent boundaries at trenches with subduction zones where crust is destroyed, and a transform boundary with a fault. Features such as island arcs, rising magma, and hotspots are labeled.

Cutaway diagram of Earth's interior showing the crust, mantle, outer core, and detailed inner core, which is divided into the outer-inner core and inner-inner core. The diagram includes labeled axes, poles, and scale bars indicating core diameters.

Diagram showing three tectonic plates labeled A, B, and C on two globe cross-sections, illustrating convergent, divergent, and transform plate boundaries with arrows and labels.

Rocky cliffs and a deep rift valley with a grassy floor run through Thingvellir National Park in Iceland, marking the crest of the Mid-Atlantic Ridge.

A world map uses color bands to show the age of Earth's oceanic crust in millions of years, with red marking the youngest crust along mid-ocean ridges and blue representing the oldest crust farther from spreading centers.

Illustration comparing six major types of volcanic eruptions: Plinian, Pelean, Vulcanian, Icelandic, Hawaiian, and Strombolian, each shown with labeled cross-sections depicting eruption style, ash, lava, or gas clouds.

Cross-sectional diagram of a subduction zone showing oceanic crust moving beneath continental crust, with features labeled including transform fault, oceanic ridge, trench, accretionary wedge, rising magma, and the Benioff-Wadati zone.

A four-panel diagram illustrates the process of trench rollback and back-arc basin formation at an oceanic subduction zone. Each panel shows a cross-section of Earth's crust and upper mantle, with a subducting oceanic plate, overlying plate, trench, volcanic arc, and melted rock in the asthenosphere. The sequence demonstrates how the trench and volcanic arc migrate, rifting forms behind the arc, and a back-arc basin develops as plates move and new crust forms.

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Topics

paleocontinent subduction Wilson cycle supercontinent cycle rifting earthquake supercontinent continental drift continent How are mountains formed?Climate Biosphere ecosystem erosion Weather seismicity river geography Earth sciences geology

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Key People

Walter Alvarez

Walter Alvarez

American geologist

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J. Tuzo Wilson

Canadian geologist

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