Chalk Group Lithostratigraphy: East Anglia - Chalk Rock

An indurated chalk bed that has traditionally been used to mark the base of the Upper Chalk, but occurs rather sporadically in East Anglia (eg. Mundford area, nr Thetford, Norfolk and Bury St. Edmunds district, Suffolk) (Mortimore & Wood, 1986; Bristow, 1990). In the Bury St. Edmunds district, it locally consists of up to 0.3 m of hard, yellow, nodular chalk that is richly fossiliferous with elements of the 'Reussianum Fauna' (Bristow, 1990; Mortimore & Wood, 1986). The latter fauna helps to establish a correlation with the Hitch Wood Hardground, the highest of three suites of hardgrounds that form Bromley & Gale's (1982) Chalk Rock 'Formation'. The poor, non feature-forming character of the Chalk Rock in East Anglia, and the fact that its base is stratigraphically younger than the base of the Chalk Rock in the Chilterns, means that it has been replaced by the Brandon Flint Series as a marker for the base of the Upper Chalk.

Macrofossil Biozonation: S. plana Zone

Correlation: see Correlation with other UK Chalk Group successions

References

BROMLEY, R G & GALE, A S. 1982. The lithostratigraphy of the English Chalk Rock. Cretaceous Research, Vol. 3, 273 - 306.

MORTIMORE, R N & WOOD, C J.1986. The distribution of flint in the English Chalk, with particular reference to the 'Brandon Flint Series' and the high Turonian flint maximum. In SIEVEKING, G de C & HART, M B. The scientific study of flint and chert. Cambridge University Press, Cambridge.

See: Chalk Rock (Chilterns Region), Reussianum Fauna, Brandon Flint Series, Upper Chalk (East Anglia)