Southern Region Chalk Group Lithostratigraphy: Bristow et al. (1997) - Zig Zag Chalk
The Zig Zag Chalk (lower boundary reference section: foot of Zig Zag Hill [ST 8911 2071] ), comprises c. 50 m of firm, pale-grey to off-white, blocky chalk, rhythmically bedded with soft grey marls in the lower part, becoming massively bedded with thin, grey marls in the upper part (Bristow et al., 1997). Key marker beds are the Cast Bed at the base, Jukes-Browne Bed 7 around the middle of the unit, and the Plenus Marls marking the top of the unit (Bristow et al., 1997). The Zig Zag Chalk equates with the upper part of the Chalk Marl and the Grey Chalk (plus White Bed where developed) of traditional classifications (Bristow et al., 1997).
Macrofossil Biozonation: A. rhotomagense Zone (pars), A. jukesbrownei Zone, C. guerangeri Zone, M. gelinianum Zone (pars)
Correlation: see Correlation with other Southern Region Chalk Group classifications
see Correlation with other UK Chalk Group 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.
See: marl, Cast Bed, Jukes-Browne Bed 7, Plenus Marls, Chalk Marl (traditional classification), Grey Chalk (traditional classification), White Bed (traditional classification)