Southern Region Chalk Group Lithostratigraphy: The North Downs (Robinson, 1986) - Broadstairs Member

The Broadstairs Member (composite stratotype: north side of St. Margarets Bay [TR 371 446] to Kingsdown Rifle Range [TR 380 473], Pegwell [TR 368 640] and Joss Bay [TR 398 702]), with a composite thickness of 58.5 m, comprises soft, white flinty chalk, with thin marl seams in the lower part (Robinson, 1986). The succession contains conspicuous flint marker beds, particularly in the middle part of the succession, between the Oldstairs Bay Flint and Bedwell's Columnar Flint, and this interval was named the Kingsdown Beds by Robinson (1986). The lower boundary of the member is the East Cliff Marl 2, or in condensed sections, the Rochester Hardground (Robinson, 1986). The top of the member is the upper surface of the Barrois Sponge Bed, the latter locally being condensed into a hardground (Clandon Hardground) (Robinson, 1986). Inoceramid bivalves are locally common through the succession, especially Platyceramus (locally forming laterally extensive shell drifts), Volviceramus involutus and Cladoceramus undulatoplicatus (Robinson, 1986). Key named marker beds are, in ascending order, the East Cliff Marl 2, White Fall Marl, Hope Point Marls, Otty Bottom Marls, Oldstairs Bay Flint, Pegwell Inoceramid Band, Chartham Flint, Bedwell's Columnar Flint, Whitaker's 3" Flint, the Barrois Sponge Bed and the Clandon Hardground (Robinson, 1986).

Macrofossil Biozonation: M. coranguinum Zone

Correlation: see Correlation with other lithostratigraphical schemes for the Southern Region

see Correlation with other UK regions

References

ROBINSON, N D.1986. Lithostratigraphy of the Chalk Group of the North Downs, southeast England. Proceedings of the Geologists' Association, Vol. 97, 141-170.

See: flint, marl (plus key markers highlighted above)