Back حوض القوس الخلفي Arabic Zaoblouková pánev Czech Backarc-Becken German حوضه پشت‌کمانی Persian Bassin arrière-arc French Cekungan busur belakang ID Bacino di retroarco Italian 背弧海盆 Japanese 배호분지 Korean Bacia de retroarco Portuguese

Back-arc basin

Cross-section through the shallow part of a subduction zone showing the relative positions of an active magmatic arc and back-arc basin, such as the southern part of the Izu–Bonin–Mariana Arc.

A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of them result from tensional forces, caused by a process known as oceanic trench rollback, where a subduction zone moves towards the subducting plate.[1] Back-arc basins were initially an unexpected phenomenon in plate tectonics, as convergent boundaries were expected to universally be zones of compression. However, in 1970, Dan Karig published a model of back-arc basins consistent with plate tectonics.[2]

Cross-section sketch showing the development of a back-arc basin by rifting the arc longitudinally. The rift matures to the point of seafloor spreading, allowing a new magmatic arc to form on the trenchward side of the basin (to the right in this image) and stranding a remnant arc on the far side of the basin (to the left in this image).
  1. ^ Cite error: The named reference :4 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference :0 was invoked but never defined (see the help page).

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