Chichester and Bognor district - Sheet Explanation for sheet E317
Price £9.00(no VAT)
Sheet Explanations provide a brief description and interpretation of the geology of the relevant BGS 1:50 000 scale map sheet area. More detailed geological information for the same area is available via the Sheet Descriptions.
Sheet Explanations are printed A5 booklets and are available either singly, or as a pack together with the relevant 1:50 000 scale map, where this map is available.
The Chichester and Bognor district lies on the south-western edge of the Weald, stretching from the South Downs to the coast at Selsey Bill. Geologically, it lies within the Wessex basin, on the southern limb of the Wealden Anticlinorium. The oldest formations known to be present at depth are of Devonian and Carboniferous age, but the main period of basin development and sedimentary deposition occurred during the Mesozoic, and a thick sequence of Jurassic strata underlies the Cretaceous rocks that outcrop at the surface. Sedimentary deposition was eventually terminated in mid-Cainozoic times, when extensive earth movements resulted in the formation of a series of large en échelon folds, each marking major faults at depth.
This brief account describes the geology of the district. The oldest exposed strata are part of the Lower Cretaceous Wealden 'Group'. Passing south, these are successively overlain by the Lower Greensand Group, Gault and Upper Greensand formations and the Upper Cretaceous Chalk Group. Cainozoic (Palaeogene) strata underlie the broad coastal plain, and include the Reading Formation, London Clay Formation and the Bracklesham Group.
Author Aldiss D T
ISBN 0852724357
Sheet(s) Covered E317
Year Published 2003
