Weald Basin

[4] The Weald basin gently subsided throughout the Jurassic, Cretaceous and Early Tertiary leading to a thick succession of sedimentary rocks being deposited.

[5] The overall uplift produced by the Tertiary inversion in the eastern Wealden basin has been estimated to be as much as 1525 m; which as a result of the large amount of Mesozoic sediments does not reveal the underlying Paleozoic basement.

[2] Utilising estimations of the original thickness of Chalk (400–460 m) and other Mesozoic strata indicate a complex fold structure which, in the event it was not eroded during uplift, attained a crestal elevation of 1400 m over what is today Ashdown Forest.

The Weald Basin has yielded significant quantities of gypsum from Jurassic Purbeck beds and a number of brickworks exploit the lower Cretaceous clays.

[8] The existence of the same strata within the Weald basin which are the source rocks for the Wytch Farm oilfield in Dorset led to an interest in the petroleum potential of the Wealden anticline, with exploration taking place on Ashdown forest examining the Ashdown Anticline, a large structure over 30 km long x 7 km wide, located in the centre of the Weald Basin in north Sussex; significant quantities of natural gas were found but oil was absent.

[9] Oil and gas have subsequently been found at a number of sites in the Weald including Singleton and Storrington in West Sussex, Godstone and Lingfied in Surrey, and Cowden in Kent.

Section across southern England showing the inverted nature of the Weald Basin
Geologic map of southeast England and the region around the English Channel , showing the Weald-Artois anticline and therefore the modern day form of the Weald Basin in its regional context
Cross-sectional diagram of eroded layers of geological anticline with locations of towns indicated
Geological section from north to south of the Wealden Anticline, note the unsymmetrical lower Cretaceous/Jurassic sediments in the core of the anticline. The diagram has undergone extensive vertical exaggeration