Southern Region Chalk Group Lithostratigraphy: Bristow et al. (1997) - Lewes Nodular Chalk

From Earthwise
Jump to navigation Jump to search

The Lewes Nodular Chalk, 45 to 60 m thick, mostly equates with the Lewes Chalk of Mortimore (1986a), except that the base of the unit is defined by the upward appearance of hard, nodular, regularly flinty chalk, forming a major positive feature; the Glynde Beds, at the base of the Lewes Chalk of Mortimore (1986a) forming the top of the New Pit Chalk of Bristow et al. (1997). In parts of Wiltshire (eg. Charnage Down [ST 836 328], near Mere), the base of the Lewes Chalk is marked by the Chalk Rock, comprising a closely welded succession of the bottom, middle and upper hardground suites of Bromley & Gale's (1982) Chalk Rock 'Formation'. The top of the Lewes Nodular Chalk is marked by the change from hard, nodular chalk with common nodular flints, to fine-grained, soft to firm chalk with common tabular and semitabular flints, approximately coincident with Shoreham Marl 2 of Mortimore (1986a), although in some areas occurring slightly above this horizon (Bristow et al., 1997).

Macrofossil Biozonation: upper T. lata Zone, S. plana Zone & M. cortestudinarium Zone

Correlation: see Correlation with other Southern Region successions

see Correlation with other UK successions


BRISTOW, C. R., MORTIMORE, R. N. & WOOD, C. J. 1997. Lithostratigraphy for mapping the Chalk of southern England. Proceedings of the Geologists' Association, Vol. 108, 293-315.

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

See: Lewes Chalk (Mortimore, 1986a), flint, Glynde Beds, New Pit Chalk (Bristow et al., 1997), Shoreham Marl 2.