EPSC 201 Lecture Notes - Lecture 6: Fracture Zone, Oceanic Trench, Convergent Boundary
5 Feb 2016
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*zone where two tectonic plates moving towards each other come together at their plate boundaries. At the subduction zone, where the oceanic crust sinks beneath the continental crust, a deep oceanic trench or valley is created. They are the deepest part of the ocean floor* One plate sinks back into the mantle (subduction) Continental crust cannot be subducted as it is too buoyant. The new trench forms, and the downgoing plate slowly sinks down in the asthenosphere. *when an oceanic plate collides with a continental plate, the crust forming the oceanic plate gets bent and pulled under the continental crust. Because the rocks that form the oceanic crust are denser and thinner than the rocks that form the continental crust! Accretionary prism is a wedge-shaped mass of sediment that is scraped off the subducting oceanic plate. Similar to oceanic-continental convergence in that one of the plates is subducted under the other during the collision!
