What are Foreland sets?
A foreland basin system is defined as: (a) an elongate region of potential sediment accommodation that forms on continental crust between a contractional orogenic belt and the adjacent craton, mainly in response to geodynamic processes related to subduction and the resulting peripheral or retroarc fold-thrust belt; (b) …
How did the foreland basin form?
Foreland basins are associated with regions of compressional tectonics. They are formed primarily as a result of the downward flexing of the lithosphere in response to the weight of the adjacent mountain belt, though many geological and geodynamic processes combine to control their subsequent evolution.
What is retro arc basin?
A type of back-arc basin which is floored by continental crust. The main sediments are fluvial, deltaic, or marine, derived from the uplifted area behind the arc. From: retro-arc basin in A Dictionary of Earth Sciences » Subjects: Science and technology — Earth Sciences and Geography.
What does the presence of a foreland basin indicate?
Lithospheric strength envelopes The foreland basin typically shows a thermal and rheological structure similar to a rifted continental margin with three brittle layers above three ductile layers. The temperature underneath the orogen is much higher and thus greatly weakens the lithosphere.
What is a molasse in geology?
Molasse, thick association of continental and marine clastic sedimentary rocks that consists mainly of sandstones and shales formed as shore deposits. The depositional environments involved include beaches, lagoons, river channels, and backwater swamps.
How are back-arc basins 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.
How is a flexural basin formed?
Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithosphere to bend, by a process known as lithospheric flexure.
Where are basins located?
Basin and Range Province, arid physiographic province occupying much of the western and southwestern part of the United States. The region comprises almost all of Nevada, the western half of Utah, southeastern California, and the southern part of Arizona and extends into northwestern Mexico.
Why Mizoram is called molasses basin?
Mizoram is also known as Molasses basin because it is made up of unconsolidated deposits. With its mountainous geography it contains many foreland basins which is a valley type depression running parallel to mountains. When unconsolidated deposits fill up these depressions it is called molasses basin.
What are the characteristics of the foreland basin?
The greatest thickness of foreland basin sediments borders the fold-thrust belt reflecting enhanced subsidence caused by thrust-sheet loading and deposition of sediments. Another characteristic feature of retroarc foreland basins is that the proximal basin margin progressively becomes involved with the propagating fold-thrust belt ( Figure 3.18).
How are variations in forelandbasinsystemsrisited depend on tectonic setting?
These variations depend on tectonic settingandthenatureoftheassociatedfold-thrustbelt.Continuedgrowthofthefold- thrust belt by horizontal shortening requires foreland lithosphere to migrate toward the fold-thrust belt.
What kind of unroofing is in the foreland basin?
Progressive unroofing in the fold-thrust belt should lead to an “inverse” stratigraphic sampling of the source in foreland basin sediments as illustrated in Figure 3.18. Such a pattern is well developed in the Cretaceous foreland basin deposits in eastern Utah ( Lawton, 1986).
How are foreland basins related to orogenic wedges?
Foreland basins are adjacent to orogenic wedges and accommodate the influx of detrital material arising from erosion of the wedge. Kent C. Condie, in Earth as an Evolving Planetary System (Third Edition), 2016
