Subduction usually happens at a somewhat steep angle directly at the convergent plate boundary. However, anomalous shallower angles of subduction, as well as ones that are exceptionally steep, are known to exist. When the slab subducts nearly horizontally, it is called flat-slab subduction (subducting angle less than 30 degrees).
Flat-slab subduction occurs along most of the coast of Chile and parts of Argentina. In these areas, oceanic crust is being consumed at shallow depths (less than 500 km) by rapidly moving slabs of continental crust.
The consumption of oceanic crust by continents can be seen in many places around the world where ocean floors have been raised up and become part of the land surface. One example is the ocean floor off the coast of California where sinking islands are forming due to the action of marine currents on top of the remaining solidified lava flows from ancient volcanoes.
Another example is the Mid-Atlantic Ridge where ocean floors are being consumed by deep-sea earthquakes caused by the movement of lithospheric plates relative to one another. The resulting motions raise and lower coastal regions worldwide.
In conclusion, subduction happens at a plate boundary but does not always do so. If the slab subducts at a very shallow angle or nearly horizontal, it is called flat-slab subduction. This type of subduction occurs along most of Chile and parts of Argentina.
Subduction is a geological phenomenon that occurs along the convergent borders of tectonic plates, in which one plate slides beneath another and is pushed to sink due to high gravitational potential energy in the mantle. Plates contain both oceanic and continental crust. As two plates collide and one plate dives into the other, the upper plate is forced downwards with great force generating seismic waves and causing volcanoes to erupt. The result is a large area of mountains and islands covered in water.
When two plates collide, they do not always completely fuse together. Sometimes part of each plate remains above or below the other. Where this happens, there are often deep trenches between them which can be thousands of meters deep. In areas where subduction does not occur, sediment builds up on the upper surface of one plate but gets dragged back down toward the middle of the earth where it forms new rock layers. Subduction zones are different because there they go all the way through the solid earth's core and return to the surface again miles away.
The word "subduction" comes from the Latin sub meaning "below" and ducere meaning "to lead". It refers to the fact that as one plate dips beneath the other, it leads an indentation in its path.
In conclusion, subduction is the process by which one plate sinks beneath another.
The word "subduction" comes from the Latin sub, under, and ducere, to lead or guide. In this context, it means to lead something deeper into the earth.
The leading edge of an oceanic plate sinks as it collides with and is dragged underneath another plate. This process forms a trench on the leeward side of the sinking region. Sulfur dioxide and other gases released at the surface combine with water vapor to form sulfuric acid clouds that can damage vegetation and cause acid rain. On land, subduction causes earthquakes and controls the distribution of minerals.
Subduction is important for understanding how plates move and why some areas experience many earthquakes while others are quiet. It also has significant effects on climate through processes such as volcanism and ocean circulation.
Subduction starts when one plate dives below another. The lower plate bends and often crumples before finally being forced down into the mantle. The transition between the two plates may be abrupt, with no evidence of their previous contact, or gradual where they overlap and slide past each other.
Subduction zones are areas where this phenomenon happens. There are three main types of subduction zone boundaries: divergent, parallel, and transverse.
Divergent boundaries occur when two moving plates meet head-on, without changing their directions or speeds. These are usually steep cliffs with many faults marking where rock has been uplifted or dropped relative to its surroundings. Divergent boundaries can be either oceanic or continental. Oceanic divergent boundaries are marked by deep trenches such as the Pacific Ocean's Marianas Trench or Indian Ocean's Makran Fault Zone. Continental divergent boundaries include the Alps and Appalachians.
Parallel boundaries occur when two plates move toward each other at nearly the same speed but in opposite directions. They appear as long bands of destroyed land with few if any fractures or cliffs. Parallel boundaries can also be very smooth; there may be no visible break between the plates beyond some depth. The African continent exhibits this type of boundary with its Eifel Tower-like mountains created by ancient cratons that were once part of an ancient supercontinent called Gondwana.