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Continental drift - Coggle Diagram
Continental drift
Convergent Boundaries
Definition
When two tectonic plates collide, the boundary between them is a convergent boundary.
What happens at a convergent boundary depends on the kind of crust at the leading edge of each tectonic plate.
When two plates collide, the density of the plates determines which one comes out on top.
continental–continental
occurs when two plates carrying continental crust push together. Because both crusts have the same density, neither crust can sink beneath the other
If the plates keep moving, their edges crumple and fold. In some cases, the folded crust can be pushed up high enough to form mountains.
oceanic–oceanic
occurs where one plate with oceanic crust sinks, or subducts, under another plate with oceanic crust.
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Two main features form from an oceanic–oceanic subductions: deep–ocean trenches (are like deep canyons that form in the ocean floor as a plate sinks. Most deep-ocean trenches are found in the Pacific Ocean) and island arcs (chains of volcanic islands that form on the top of the plate, parallel to a deep–ocean trench. As oceanic crust of the sinking plate melts, magma rises through the top plate. Over time, the flows build up a series of islands).
ocean–continental
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At these sites, deep ocean trenches also form, along with coastal mountains.
Divergent Boundaries
When two tectonic plates separate, the boundary between them is called a divergent boundary.
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As the tectonic plates move away from each other, the seafloor spreads apart and magma fills the gap.
As this new crust forms, the older crust gets pushed away. New sea floor forms at divergent boundaries.
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Transform Boundaries
When two tectonic plates slide past each other horizontally, the boundary between them is a transform boundary.