Collisions in Earth's Crust

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Lithosphere Noun

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[lith-uh-sfeer]

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Lithosphere

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The rigid outer layer of the Earth, consisting of the crust and upper mantle, which is broken into tectonic plates.

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Example: This diagram shows the lithosphere, which includes the crust and solid upper mantle, during a collision where a dense oceanic plate sinks under a continental plate.

Front

Tectonic Plate Noun

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[tek-ton-ik pleyt]

Back

Tectonic Plate

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A large, rigid piece of Earth's lithosphere that moves slowly over the underlying asthenosphere, causing geologic activity.

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Example: This diagram shows two tectonic plates colliding, where one plate slides under the other, causing magma to rise and form a volcano.

Front

Plate Tectonics Noun

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[pleyt tek-ton-iks]

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Plate Tectonics

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The scientific theory describing the large-scale motion of the tectonic plates that make up Earth's lithosphere.

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Example: This world map shows how the Earth's crust is broken into large, distinct pieces called tectonic plates, which move and interact at their boundaries.

Front

Mid-Ocean Ridge Noun

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[mid-oh-shuhn rij]

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Mid-Ocean Ridge

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An underwater mountain system formed by plate tectonics where new ocean lithosphere is created at a divergent boundary.

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Example: This diagram shows magma rising from the mantle to create new oceanic crust at a mid-ocean ridge, pushing tectonic plates apart.

Front

Subduction Zone Noun

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[suhb-duhk-shuhn zohn]

Back

Subduction Zone

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A geologic region where one tectonic plate moves under another and is forced to sink into the mantle.

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Example: This diagram shows a subduction zone, where a denser oceanic crust plate slides underneath a continental crust plate, creating a deep ocean trench.

Front

Mantle Noun

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[man-tl]

Back

Mantle

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The layer of the Earth between the crust and the core, where convection currents drive tectonic plate motion.

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Example: This diagram shows the Mantle as the thickest layer of the Earth, located between the thin outer Crust and the hot inner and outer Cores.

Front

Divergent Boundary Noun

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[dahy-vur-juhnt boun-dree]

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Divergent Boundary

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A boundary where two tectonic plates are moving away from each other, often resulting in rifting and volcanism.

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Example: This diagram shows two oceanic crust plates moving away from each other, allowing magma from below to rise and create new crust at the boundary.

Front

Convergent Boundary Noun

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[kuhn-vur-juhnt boun-dree]

Back

Convergent Boundary

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A boundary where two tectonic plates move toward each other, resulting in geologic features like collision or subduction.

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Example: This diagram shows two tectonic plates colliding, where the denser oceanic crust sinks beneath the continental crust, forming a trench and a volcanic arc.

Front

Transform Boundary Noun

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[trans-fawrm boun-dree]

Back

Transform Boundary

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A boundary where two tectonic plates slide past one another horizontally, often causing frequent and powerful earthquakes.

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Example: This diagram shows a transform boundary where two tectonic plates slide horizontally past each other, causing stress that results in earthquakes along the fault line.

Front

Intraplate Deformation Noun

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[in-truh-pleyt dee-fawr-mey-shuhn]

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Intraplate Deformation

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The folding, stretching, or fracturing of rock within a tectonic plate, occurring away from its primary boundaries.

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Example: This topographic map shows the vast, elevated Tibetan Plateau, which formed far from a plate edge due to the collision of the Indian and Eurasian plates.