What defines a back arc region?
The back-arc region is the area behind a volcanic arc. In island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs.
What is a back arc spreading center?
: a geological region that forms at a subduction zone when the overriding plate thins and begins to spread out —often used before another noun The hot springs there are not connected at all to the midocean ridge system: they lie on what is called a back-arc spreading center, a geologic feature that occurs not where two …
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 are back-arc basins less common today?
The restricted width of back-arc basins is due to magmatic activity being reliant on water and induced mantle convection, limiting their formation to along subduction zones. Spreading rates vary from only a few centimeters per year (as in the Mariana Trough), to 15 cm/year in the Lau Basin.
How do back-arc basins form quizlet?
Back arc basins form because: The subduction of old oceanic lithosphere may make the volcanic arc move toward the trench and produce an extensional back-arc basic behind the arc. Why is the composition of some of the magna in volcanic arcs different from that in oceanic ridges?
Where do forearc basins form?
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.
Which best describes how wedge basins form quizlet?
How does a wedge basin form? When two plates collide, the non-subducting plate scrapes and subducting plate and forms a depression where sediments gather.
What is a forearc region?
The forearc is the region between the subduction zone and the volcanic chain (volcanic arc).
What is an example of a volcanic island arc?
Keys to the Interpretation of Geological History. A volcanic arc is a chain of volcanoes,hundreds to thousands of miles long,that forms above a subduction zone.
What is back arc spreading?
back-arc spreading The formation of the oceanic crust of the marginal basins, which is thought to occur by a process similar to that of normal oceanic crust, but involving a convective system developed over a subducting lithospheric plate.
What is back arc?
The back-arc region is the area behind a volcanic arc. In island volcanic arcs it consists of back-arc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs. In continental arcs the back-arc region is part of continental platform, either dry land (subaerial) or forming shallow marine basins.