A team of geologists from the University of California, Berkeley, has discovered how a tectonic plate sank beneath another tectonic plate, a process known as subduction. The discovery, published in the journal Nature, could help scientists better understand the evolution of the Earth's crust and the formation of mountain ranges.

Subduction occurs when one tectonic plate, usually a denser oceanic plate, collides with another, usually a less dense continental plate. The oceanic plate is forced to sink beneath the continental plate, and as it does, it melts and forms magma. This magma rises to the surface and erupts to form volcanoes.

The geologists studied a region in the Pacific Ocean where the Pacific Plate is subducting beneath the North American Plate. They used seismic imaging to map the structure of the subduction zone, and they found that the oceanic plate was sinking at an angle of about 45 degrees. This is much steeper than the angle at which most other subduction zones occur, which is typically around 10 degrees.

The geologists believe that the steep angle of subduction in this region is due to the fact that the Pacific Plate is relatively young and hot. This means that it is less dense than older, cooler oceanic plates, and it is therefore more easily subducted.

The discovery of this steep subduction zone could help scientists better understand the evolution of the Earth's crust. It could also help them understand the formation of mountain ranges, such as the Andes Mountains in South America, which are formed by the subduction of the Nazca Plate beneath the South American Plate.

Source: University of California, Berkeley