Coniacian 3

The basal sequence boundary is not well defined in Sussex, being marked by an interval of nodular chalk between the Beeding and Light Point Hardgrounds (Grant et al., 1999). In Kent, the boundary equates with Corn Hill Hardground 1, and the overlying lowstand systems tract comprises either nodular chalk horizons (Sussex) or further hardgrounds (Kent; Corn Hill Hardgrounds 2-3). A transgressive surface is marked by hardgrounds in both Sussex (Light Point Hardgrounds) and Kent (Corn Hill Hardground 4), and a thin (1-2 m, but less than 1 m in Sussex) transgressive systems tract includes further hardgrounds in Kent (Corn Hill Hardgrounds 5 & 6) that are interpreted as further transgressive pulses (Grant et al., 1999). The maximum flooding surface is Corn Hill Hardground 7 in Kent, and the upper of the paired Light Point Hardgrounds in Sussex (Grant et al., 1999). The highstand systems tract comprises a couple of metres of flinty chalk (Grant et al., 1999) in the upper part of the Light Point Beds of Mortimore (1986).

References

GRANT, S F, COE, A L, ARMSTRONG, H A. 1999. Sequence stratigraphy of the Coniacian succession of the Anglo-Paris Basin. Geological Magazine, 136, 17–38.

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