What is the fore arc basin?

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 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.

How does fore arc basin form?

Forearc basin is a sedimentary basin formed in the arc-trench gap between a volcanic arc and plate subduction zone (Figure 1) [1].

What does arc mean in geology?

A chain of volcanic activity
« Back to Glossary Index. A chain of volcanic activity, typically in a curved pattern, rising from a subduction zone. The arc is on the overriding plate, typically a few hundred kilometers from the trench, but parallel to the trench.

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. This category is also used for Melange.

What’s a foreland?

foreland. / (ˈfɔːlənd) / noun. a headland, cape, or coastal promontory. land lying in front of something, such as water.

What is back-arc volcanism?

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 island arc in geography?

As the name implies, island arcs are typically a curving chain of volcanic islands occurring around the margin of ocean basins. The curvature and the volcanic nature are important characteristic features.

What forms island arcs?

Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries (such as the Ring of Fire). Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle along the subduction zone.

Where are Ophiolites found?

Ophiolites have been found in Cyprus, New Guinea, Newfoundland, California, and Oman. The Samail ophiolite in southeastern Oman has probably been studied in the greatest detail. The rocks probably formed in the Cretaceous not far from the what is now the Persian Gulf.

What is melange composed of?

mélange A mappable body of rock composed of broken rock fragments, of all sizes and many origins, in a sheared matrix. A mélange with a chaotic nature, initially of sedimentary origin, is called an ‘olistostrome’.

What is Foreland Port?

The foreland is the ocean-ward mirror of the hinterland, referring to the ports and overseas markets linked by shipping services from the port. It is above all a maritime space with which a port performs commercial relationships, namely its overseas customers.

What do you mean by cape?

Definition of cape (Entry 2 of 2) 1 : a sleeveless outer garment or part of a garment that fits closely at the neck and hangs loosely over the shoulders. 2 : the short feathers covering the shoulders of a fowl — see duck illustration.

What defines a back-arc region?

Is the Sea of Japan a back-arc basin?

The Japan Sea, a mature backarc basin in the northwestern Pacific region, is located between the Asian continent and the northeastern and southwestern Japan Arcs (Fig. 1).

Where are island arcs?

the Pacific Ocean
Some well-known examples of island arcs are Japan, Aleutian Islands of Alaska, Mariana Islands, all of which are in the Pacific, and the Lesser Antilles in the Caribbean. The abundance of volcanic rocks around the Pacific Ocean has led to the designation of the Pacific margin as a “Ring of Fire”.

What are island arcs and how are they formed?

What is a forearc basin?

Fore-arc basins lie behind the topographic high-point of the wedge, which in places forms an outer (sedimentary) island arc. Fore-arc sediments lie unconformably on accretionary wedge material and show progressive shoaling.

What type of geologic sequence is formed in the forearc?

The constant circulation of material in the forearc region (accretionary prism, forearc basin and trench) generates a mixture of igneous, metamorphic and sedimentary sequences.

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.