Ashdown Formation

Ashdown Formation
Stratigraphic range: Late Berriasian to Valanginian
An exposure of the Ashdown Formation on the East Sussex coast.
TypeGeological formation
Unit ofWealden Group
Sub-unitsFairlight Clays
UnderliesWadhurst Clay Formation
OverliesDurlston Formation
Thicknesstypically in the range 200-230 m
Lithology
PrimarySiltstone, Sandstone
OtherMudstone, Clay
Location
Country UK
ExtentWeald Basin
Type section
Named forAshdown Forest

The Ashdown Formation is a geological unit, which forms part of the Wealden Group and the lowermost and oldest part of the now unofficial Hastings Beds. These geological units make up the core of the Weald in the English counties of East Sussex and Kent.

The other component formations of the Hastings Beds are the overlying Wadhurst Clay Formation and the Tunbridge Wells Sand Formation. The Hastings Beds in turn forms part of the Wealden Supergroup which underlies much of South East England. The sediments of the Weald of East Sussex, including the Ashdown Formation, were deposited during the Early Cretaceous Period, which lasted for approximately 40 million years from 140 to 100 million years ago. The Ashdown Formation is of Late Berriasian to Early Valanginian to age.[1] The formation takes its name from the Ashdown Forest in the High Weald of Sussex.

  1. ^ Hopson, P.M., Wilkinson, I.P. and Woods, M.A. (2010) A stratigraphical framework for the Lower Cretaceous of England. Research Report RR/08/03. British Geological Survey, Keyworth.