Oceans Ate Alaska Into The Deep Full Album Download
Josephine Heathershaw
Accretionary wedges form as sediments from the dense, subducting tectonic plate are scraped off onto the less-dense plate. Sediments often found in accretionary wedges include basalts from the deep oceanic lithosphere, sedimentary rocks from the seafloor, and even traces of continental crust drawn into the wedge. The most common type of continental crust found in accretionary wedges is volcanic material from islands on the overriding plate.
Accretionary wedges are roughly shaped like a triangle with one angle pointing downward toward the trench. Because sediments are mostly scraped off from the subducting plate as it falls into the mantle, the youngest sediments are at the bottom of this triangle and the oldest are at the more flattened area above. This is the opposite of most rock formations, where geologists must dig deep to find older rocks.
Deep Disposal
The Challenger Deep is the deepest part of the ocean. It sits on a subduction zone, where the Pacific plate is subducting beneath the Philippine plate.
Some scientists argue that this makes the Challenger Deep the perfect place to dispose of toxic nuclear waste. The material would be far from human habitation and would melt into the Earth's molten mantle at the subduction zone. An international agreement (the London Convention) currently makes this proposed method of nuclear waste disposal illegal.