What causes back arc spreading?

What causes back arc spreading?

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 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 …

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.

How does a forearc basin form?

Forearc basins typically develop along continental margins and island arcs where oceanic plates are subducting beneath the overriding crust.

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.

What is an accretionary wedge complex?

Accretionary Wedge (aka Accretionary Prism, Subduction Complex): A wedge- or prism-shaped mass of sediments and rock fragments which has accumulated where a downgoing oceanic plate meets an overriding plate (either oceanic or continental) at a subduction zone.

What is fore arc and back arc basin?

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.

What is a forearc basin geology?

Forearc basins are marine depositional basins on the trench side of arcs (Fig. 3.16A), and they vary in size and abundance with the evolutionary stage of an arc. In continental margin arcs, such as the Sunda Arc in Indonesia, forearc basins range up to 700 km in strike length.

What is the difference between a rift basin and a foreland basin?

Foreland basins represent an endmember basin type, the other being rift basins. Space for sediments (accommodation space) is provided by loading and downflexure to form foreland basins, in contrast to rift basins, where accommodation space is generated by lithospheric extension.

What is intermontane basin?

Intermontane Basin, a wide valley between mountain ranges that is partly filled with alluvium such as New Zealand’s Mackenzie Basin. Intermontane Belt, a physiogeological region in the North American Pacific Northwest. Intermontane Plateaus, the United States physiographic region of the Intermountain West.

What is the difference between Terrane and terrain quizlet?

What is the difference between terrane and terrain? “Terrane” describes a crustal fragment consisting of a distinct and recognizable series of rock formations that has been transported by plate tectonic processes, whereas “terrain” describes the shape of the surface topography.

Which orogenic event is associated with the formation of Pangaea?

2.7 Pangaea Pangaea is a term coined by Wegener in 1912, for the super-continent formed following the Hercynian orogeny which included virtually all of the earth’s continental crust.

What causes accretionary prism?

An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary.

Where are accretionary wedges?

Sediments, the top layer of material on a tectonic plate, that accumulate and deform where oceanic and continental plates collide. These sediments are scraped off the top of the downgoing oceanic crustal plate and are appended to the edge of the continental plate.

What is a mélange in geology?

Mélange. A body of rock characterized by a lack of internal continuity of contacts or strata and by the inclusion of fragments and blocks of all sizes, both exotic and native, embedded in a fragmental matrix of finer-grained material.

What is cratonic basin?

Cratonic basins are sites of prolonged, broadly distributed but slow subsidence of the continental lithosphere, and are commonly filled with shallow water and terrestrial sedimentary rocks. They remain poorly understood geodynamically.

What is foreland in geography?

1. a headland, cape, or coastal promontory. 2. land lying in front of something, such as water.

How is Intermontane Plateau formed?

Intermontane plateaus are usually flat open highlands formed when land has been uplifted by tectonic activity. Basins are formed by run-off sediment from the surrounding mountains. Throughout the western Americas, the north-south cordillera is split into a coastal mountain range and one or two interior ranges.

What’s the difference between Terrane and terrain?