Geological investigation of the Ashdown Beds at Fairlight, East Sussex

Abstract

The coastline from Hastings eastward to Cliff End in Sussex is dominated by cliffs that expose a significant proportion of the Ashdown Formation, the lowest part of the Wealden succession described from the Weald of Sussex and Kent. The cliffs from East Hill in Hastings to Pett Beach, some 7.5 km distant to the east-northeast, are designated as a Site of Special Scientific Importance (SSSI) for its geological interest. These cliffs expose the most complete succession of terrestrial Lower Cretaceous rocks in Europe and are the principal exposure of the Ashdown Formation in the Weald. Within this SSSI the Ashdown Formation is preserved in a low amplitude northnorthwest to south-southeast trending anticline (the Fairlight Anticline) that cuts the coast between Lee Ness Ledge and Fairlight Cove. At the eastern end of this anticline adjacent to a bounding reverse fault (the Fairlight Cove Reverse Fault) the cliffs have suffered a catastrophic landslide. The British Geological Survey was commissioned by English Nature to report upon the accessible principal elements of the succession adjacent to the western limit of this landslide and to compare the beds identified with those exposed over the crest of the anticline to its opposite limb at Lee Ness Ledge (about 1.5 km to the west). This report gives a historical appraisal of the data held at BGS for this SSSI, provides outline stratigraphical logs for the accessible portion of the cliffs between the landslide and Lee Ness Ledge and discusses the significance of the exposures presently visible