GARY HINCKS / SCIENCE PHOTO LIBRARY GARY HINCKS / SCIENCE PHOTO LIBRARY
Accretionary prism. Artwork of a cross-section through the Earth's crust showing the formation of an accretionary prism at a subduction zone. A subduction zone occurs in the region where two convergent tectonic plates collide. Tectonic thrusting forces one plate beneath the other down into the mantle (orange) beneath the crust. This causes the formation of a trough or trench along the plate boundary. Sedimentary material is scraped off the subducted plate by the upper plate as they converge. This material accumulates in a prism or wedge shape (centre), filling the trough. The rock in the subducted plate melts as it is forced down and then rises again as magma. This is forced out of volcanoes (left).
Model release not required. Property release not required.