Southern Region Chalk Group Lithostratigraphy: Sussex lithostratigraphy of Mortimore (1986a) - Cuckmere Beds

From Earthwise
Jump to navigation Jump to search

The Cuckmere Beds, c. 15 m thick in Sussex, are marked by the Seven Sisters Flint at the base, and the Michel Dean Flint at the top (Mortimore, 1986a). They comprise a rather monotonous sequence of pure white, flinty chalk, mostly lacking inoceramid shell debris, except in the basal part near the Seven Sisters Flint (Mortimore, 1986a). The Seven Sisters Flint is a conspicuously thick, semitabular flint, sometimes rusty iron-stained in appearance, typically containing inoceramid bivalve shell fragments, particularly Volviceramus involutus. This flint horizon is persistent over huge geographical areas, and is an important marker for long-range correlation.

The fauna of the Cuckmere Beds is characteristically sparse, except near the Seven Sisters Flint, which has acmes of the inoceramid bivalve Volviceramus involutus immediately above and below it, and is associated with common, thick shelled (+5mm) Platyceramus (Mortimore, 1986a).

Macrofossil Biozonation: lower M. coranguinum Zone

Correlation: see Correlation with other Southern Region Chalk Group classifications

see Correlation with other UK Chalk Group successions


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, Seven Sisters Flint