Southern Region Chalk Group Lithostratigraphy: Sussex lithostratigraphy of Mortimore (1986a) - Lewes Member

From Earthwise
Jump to navigation Jump to search

The Lewes Member, 58 to 89 m thick in Sussex (Lake et al., 1987) (holostratotypes: Caburn Pit [TQ 447 089], Navigation Pit [TQ 426 099] & Beachy Head [TV 576 953]), mostly comprises a complex succession of hard, nodular, regularly flinty chalk, with marl seams and hardgrounds. Beds of softer chalk locally occur, and there are local trace fossil concentrations, especially Zoophycos. The base of the succession is the lowest of the Glynde Marls, and the top is marked by the higher of the paired Shoreham Marls (Mortimore, 1986a). Mortimore (1986a) subdivided the Lewes Member into beds as follows:

Member Beds
Lewes Shoreham
Beachy Head
Light Point
Hope Gap
South Street

select a subdivision for more information

Macrofossil Biozonation: T. lata Zone (pars), S. plana Zone & M. cortestudinarium Zone

Correlation: see Correlation with other Southern Region Chalk Group classifications

see Correlation with other UK Chalk Group successions


LAKE, R D, YOUNG, B, WOOD, C J & MORTIMORE, R N. 1987. Geology of the country around Lewes. Memoir of the British Geological Survey.

MORTIMORE, R N.1986a. Stratigraphy of the Upper Cretaceous White Chalk of Sussex. Proceedings of the Geologists' Association, Vol. 97(2), 97-139.

See: flint, marl, hardground, trace fossils, Zoophycos