How are back arc basin formed?
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 causes a forearc basin?
Between the break and the magmatic arc, a sedimentary basin filled with erosive material from the volcanic arc and substrate can accumulate into a forearc basin which overlays the oldest thrust slices in the wedge of the forearc region.
What is sedimentary basin in petroleum?
A sedimentary basin is an area of the earth’s crust that is underlain by a thick sequence of sedimentary rocks. Hydrocarbons commonly occur in sedimentary basins and are absent from intervening areas of igneous and metamorphic rocks (North, 1971).
What is basin gas?
1. n. [Geology, Shale Gas] A depression in the crust of the Earth, caused by plate tectonic activity and subsidence, in which sediments accumulate.
What is arc back?
Definition of arc-back : failure of a gas-filled or mercury-vapor rectifier to suppress the current during the inverse-voltage half of a cycle due to overheating of the anode or to other causes.
What kinds of material end up in a forearc basin?
Sediments in forearc basins, which are chiefly turbidites with sources in the adjacent arc system, range up to many kilometers in thickness. Hemipelagic sediments, which have mixed continental and oceanic sources, are also of importance in some forearc basins, such as in the Mariana Arc.
Where do forearc basins 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 is meant by sedimentary basin?
Where is Bassein oil field located?
Located 80-km off the Mumbai coast, the Bassein gas field, also called the Vasai field, was discovered in 1976 and put in production in 1988.
What is basin in oil industry?
If rich hydrocarbon source rocks occur in combination with appropriate depth and duration of burial, then a petroleum system can develop within the basin. Most basins contain some amount of shale, thus providing opportunities for shale gas exploration and production. Synonyms: sedimentary basin.
What composition of magma is initially generated in a subduction zone?
The initial magma formed as mantle rock melts beneath a subduction zone has low silica (basalt) composition. As the basalt magma rises up through the thick continental crust of North America, it melts some of that rock, too.
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 are the minerals formed in fore arc basin?
Metamorphic effects include compaction, pore-space reduction, cementation and dissolution and replacement of detrital grains by clay minerals (smectite, illite/smectite, corrensite and kaolinite), calcite, chlorite, laumontite, prehnite, pumpellyite, albite and mica, with less common quartz, haematite, pyrite and …
What do sedimentary basins contain?
How is the sedimentary basin formed?
Basin Formation Sedimentary basins are formed over hundreds of millions of years by the combined action of deposition of eroded material and precipitation of chemicals and organic debris within water environment (Figure 1.2).
How do you identify a sedimentary basin?
Sedimentary basin analysis is a geologic method by which the formation and evolution history of a sedimentary basin is revealed, by analyzing the sediment fill and subsidence. Subsidence of sedimentary basins generates the spatial distribution of accommodation infilling sediments.
Where is Salsette and Bassein?
Bassein and Salsette were situated in Maharashtra, Salsette is an island. This battle is popularly known as the Battle of Vasai.
What is the difference between convergent and back-arc basins?
At convergent boundaries, such as subduction zones, oceanic lithosphere is consumed at deep-sea trenches, leading to the eruption of chains of andesitic arc volcanoes near the edge of the overriding plate. Back-arc basins are especially diverse geologic settings because they inherently involve both of these types of plate boundaries.
What are the characteristics of back-arc basins?
Back-arc basins are typically very long (several hundreds to thousands of kilometers) and relatively narrow (a few hundred kilometers). The restricted width of back-arc basins is probably because magmatic activity depends on water and induced mantle convection and these are both concentrated near the subduction zone.
Is a subduction zone required for back-arc extension to form?
For back-arc extension to form, a subduction zone is required, but not all subduction zones have a back-arc extension feature. Back-arc basins are found in areas where the subducting plate of oceanic crust is very old.
How does back-arc rifting lead to surface spreading?
The thinning of the overriding plate at the back-arc (i.e., back-arc rifting) can lead to the formation of new oceanic crust (i.e., back-arc spreading). As the lithosphere stretches, the asthenospheric mantle below rises to shallow depths and partially melts due to adiabatic decompression melting. As this melt nears the surface spreading begins.