What is a forearc sliver?
The forearc sliver is, on average, a ~ 105-km-wide crustal block bounded at northeast by a ~ 650-km-long LVC fault zone striking parallel to the MAT. This fault system accommodates most of the oblique component of convergence between the CO and NA plates.
Why do volcanoes occur at the forearc?
A forearc basin develops in the low area between the two mountain ranges. Farther inland, the subducting plate reaches depths where it “sweats” hot water. The rising water melts rock in its path, forming a volcanic arc on the overrriding plate.
What is a four arc basin?
Forearc basins are marine depositional basins on the trench side of arcs, and they vary in size and abundance with the evolutionary stage of an arc.
What is back-arc basin in geology?
back-arc basin, submarine basin that forms behind an island arc. Such basins are typically found along the western margin of the Pacific Ocean near the convergence of two tectonic plates.
What is fore arc and back-arc?
The area between the trench and the arc is the forearc region, and the area behind the arc (i.e. on the side away from the trench) is the back-arc region.
How do back-arc basins form?
A back-arc basin is formed by the process of back-arc spreading, which begins when one tectonic plate subducts under (underthrusts) another. Subduction creates a trench between the two plates and melts the mantle in the overlying plate, which causes magma to rise toward the surface.
What defines a back-arc region?
The backarc is the region landward of the volcanic chain on the other side from the subduction zone.
How is a forearc basin formed?
Forearc basin is a sedimentary basin formed in the arc-trench gap between a volcanic arc and plate subduction zone (Figure 1) [1].
Why do forearc basins form?
Formation. During subduction, an oceanic plate is thrust below another tectonic plate, which may be oceanic or continental. Water and other volatiles in the down-going plate cause flux melting in the upper mantle, creating magma that rises and penetrates the overriding plate, forming a volcanic arc.
How is a back arc basin formed?
A Back-arc Basin is a geological formation that occurs on the ocean floor. This marine formation is most commonly identified along subduction zones, which occur where one tectonic plate moves beneath another, and island arcs, which are a kind of archipelago made up primarily of volcanos.
What is the difference between forearc and backarc regions?
The area between the trench and the arc is the forearc region, and the area behind the arc (i.e. on the side away from the trench) is the back-arc region . Initial theories proposed that the oceanic trenches and magmatic arcs were the primary suppliers of the accretionary sedimentation wedges in the forearc regions.
What is a forearc?
A forearc is the region between an oceanic trench and the associated volcanic arc. Forearc regions are found at convergent margins, and include any accretionary wedge and forearc basin that may be present.
What is the remnant arc in a back-arc basin?
This division strands a remnant arc on the side of the basin away from the trench and subduction zone, and the remnant arc shifts away from the arc axis as it reforms. Most of the sediment that reaches back-arc basins originates in the active magmatic arc.
Is the Okinawa Trough an arc or a backarc?
The Okinawa Trough is at an early stage of evolution from arc type to backarc activity [ s ]. Forearc basins are sea floor depressions located between subduction zones and their associated volcanic arc. Forearc basins receive sediments from the adjacent landmass, the island arc system, and trapped oceanic crustal material.