Farallon Plate

The Farallon Plate was an ancient oceanic tectonic plate that subducted beneath western North America. Its remnants include the Juan de Fuca and Cocos plates.

Subduction: The descent of one tectonic plate beneath another into the mantle. The Farallon Plate disappeared as it descended beneath the North American Plate.
Plate tectonics: The theory that Earth's lithosphere is divided into moving plates whose interactions shape the surface. The Farallon Plate's history is reconstructed through the motions and interactions of neighboring plates.
Panthalassa: The vast global ocean surrounding the supercontinent Pangaea during much of the Paleozoic and Mesozoic. The Farallon Plate occupied part of the ancient oceanic realm west of Pangaea.
San Andreas Fault: A major transform fault system marking motion between the Pacific and North American plates in California. Its development followed the arrival of the Pacific–Farallon spreading ridge at the continent.
North American Plate: The tectonic plate carrying most of North America and parts of the Atlantic and Arctic seafloor. Its western margin overrode the Farallon Plate for much of the plate's history.
Oceanic crust: The relatively thin, dense crust forming most of Earth's ocean floors. The Farallon Plate consisted chiefly of oceanic lithosphere created at spreading ridges.
Pacific-Farallon Ridge: The spreading ridge that separated the Pacific Plate from the Farallon Plate. This ridge produced oceanic crust and later interacted with the North American margin.
Cascade Volcanic Arc: A chain of volcanoes in the Pacific Northwest produced by subduction of oceanic plates. Present-day Juan de Fuca subduction preserves the volcanic-arc process once associated with Farallon subduction.
Laramide orogeny: A mountain-building episode that produced much of the interior western United States' Rocky Mountain region. Shallow subduction of the Farallon Plate is linked to this inland mountain-building episode.
Mid-ocean ridge: An underwater mountain chain where tectonic plates diverge and new oceanic crust forms. Seafloor spreading at ridges generated crust that became part of the Farallon Plate.

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