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

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The Hope Gap Beds, c. 3 m thick, are marked by the top surface of the Cliffe Hardground at the base, and the Hope Gap Hardground at the top (Mortimore, 1986a). They comprise beds of hard, nodular, iron stained, flinty chalk, with a pair of marl seams (Hope Gap Marls), capped by the Hope Gap Hardground, which is typically a very conspicuous nodular-textured, indurated horizon (Mortimore, 1986a). Locally these beds show evidence of synsedimentary slumping, that in some cases has disrupted and shattered flint horizons (Mortimore, 1986a).

The fauna of the Hope Gap Beds, below the Hope Gap Hardround, is dominated by the echinoid Micraster normanniae and the inoceramid bivalve Cremnoceramus; Micraster cortestudinarium occurs at and above the Hope Gap Hardground (Mortimore, 1986a).

Macrofossil Biozonation: lower M. cortestudinarium Zone

Correlation: see Correlation with other Southern Region Chalk Group classifications

see Correlation with other UK Chalk Group successions

References[edit]

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, Marl, Nodular Chalk, Hardground, Hope Gap Hardground