The Weald Basin is the main topographical feature of the area that is now southern England and northern France from Triassic to the Limestone End. His appointment at Late Cretaceous marked the formation of Anticline Wealden. The rock layer contains hydrocarbon deposits that produce coal, oil and gas.
Video Weald Basin
Formation
The Weald Basin formation began during Carboniferous, with rocks currently stored underground in low swamps that provide exploited coal to the north and east of Kent, but drill holes drilled in the 19th century failed to locate these deposits in the Weald area. Coal Carbon can be overlaid by early Triassic sediments. The sediment is lifted and blamed in Orogeny Variscan, with the land now occupied by Weald Basin being the low external folding belt to the main orogeny, which lies within the current English Channel. The remains of the mountain belt can be seen today in Devon and Cornwall in what is known as the Cornubian Massif. Unlike in Devon and Cornwall deformation causes little or no metamorphism.
Mountain belts collapse immediately after orogeny, leading to the previous northward thrust to be reactivated as a normal fault, and leading to the formation of the Weald basin, developed as an extension of the much larger Wessex Basin. The reconstruction of the early fault system geometry at Weald Basin reveals that for early history the basin of a series of normal steep errors to the north was active against the London-Brabant Massif, but it is not clear whether this reflects the origin sin-for these stones. The Weald basin is gently alleviated throughout the Jurassic, Cretaceous and Early Tertiary that leads to succession of sedimental sediments deposited. During the Beginning of Jura, a shelf dominated by northern and eastern mud flourished.
Maps Weald Basin
Reinforcement basin
As a result of the Alpine orogeny basin sandwiched between the crypt to the north and south, this resulted in the reactivation of the previous normal faults into small pricks (as happened during Variscan Orogeny) and the formation of Wealden Anticline. The two highest surfaces in the region (raised crust and rock areas), Wealden Anticline and Channel High, are superimposed earlier, Mesozoic basins, (Weald and Channel basins). This almost exact superimposition of compositions in previous extensional features extensively exemplifies perfectly the principles of structural inversion across large, well-defined geological features. The overall rapture produced by Tertiary inversion in the eastern Wealden basin has been estimated at 1525 m; which as a result of a large number of Mesozoic sediments did not reveal the underlying Paleozoic basement. Utilizing approximate Chalk native thickness (400-460 m) and other Mesozoic strata shows a complex fold structure which, if not eroded during lifting, reaches a crestal elevation 1400 m above what is currently Ashdown Forest. However it is possible that erosion continues to race with the rapture, resulting in large quantities of sediment supply to the North Sea and the English Channel
Economic resources
The coal seam was discovered when a tedious test for an initial proposal for the Channel Tunnel in Dover in 1890. This led to the development of four deep mines at Kent Coalfield in the early 20th century. The Weald Basin has produced a large number of gypsum from a Jurassic Purbeck bed and a number of bricks exploiting low limestone clays.
Inversion of the Weald Basin throughout the Cretaceous and Early Tertiary end results in Wealden Anticline formation and a smaller number of anticlines in larger structures. The discovery in 1897 natural gas while drilling for water at Heathfield railway station provides fuel for the first natural gas illumination in the UK. The existence of the same strata in the Weald Basin which is a source rock for the Wytch Farm field in Dorset leads to an interest in the oil potential of the Wealden anticline, with exploration occurring in the Ashdown forest checking Ashdown Anticline, a large structure. over 30 km long x 7 km wide, located in the center of the Weald Basin in northern Sussex; large amounts of natural gas are found but no oil. Oil and gas were later found at sites in Weald including Singleton and Storrington in West Sussex, Godstone and Lingfied in Surrey, and Cowden in Kent. In 2009, recoverable oil reserves at Weald Basin were estimated at one and a half million tonnes. In 2010, Weald Basin contributed 18% of land gas and less than 5% of the UK's groundwater production. In August 2013 there was a significant opposition to the growing hydraulic fracturing in southeastern England centered on Balcombe where exploration wells were planned and Balcombe drilling protests were under way.
The BGS/Department of Energy and Climate Change (DECC) report from May 2014 indicates that there is a possibility for the extreme crude oil extraction (LTO) in Weald Basin and an average of 4.4 billion barrels (700 million cubic meters) is recommended. The overall estimated range is 2.2 to 8.6 billion barrels (350 to 1,370 million cubic meters). The data is said to have a "high degree of uncertainty", and the amount that can be generated is unknown, and can be zero.
See also
- Weald Region in South East England
- Eastern Sussex Geology
References
Source of the article : Wikipedia
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