Southern Region Chalk Group Lithostratigraphy: Sussex lithostratigraphy of Mortimore (1986a) - Whitecliff Beds: Difference between revisions
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The Whitecliff Beds, c. 27 m thick locally in the Isle of Wight, are marked by the Whitecliff Marl at the base, and the Portsdown Marl at the top (Mortimore, 1986a). The chalk of this interval is typically very soft and flinty, the flints usually forming very large 'Potstones', one such being the Whitecliff Flint in the lower part of the succession. Weakly developed marls occur beneath the Whitecliff Flint, and locally on Portsdown (Downend Quarry [SU 601 067]), there is the anomalous development of a condensed succession of hardgrounds and phosphatic chalk (Mortimore, 1986a). | The Whitecliff Beds, c. 27 m thick locally in the Isle of Wight, are marked by the Whitecliff Marl at the base, and the Portsdown Marl at the top (Mortimore, 1986a). The chalk of this interval is typically very soft and flinty, the flints usually forming very large 'Potstones', one such being the Whitecliff Flint in the lower part of the succession. Weakly developed marls occur beneath the Whitecliff Flint, and locally on Portsdown (Downend Quarry [SU 601 067]), there is the anomalous development of a condensed succession of hardgrounds and phosphatic chalk (Mortimore, 1986a). | ||
Latest revision as of 15:01, 4 October 2013
The Whitecliff Beds, c. 27 m thick locally in the Isle of Wight, are marked by the Whitecliff Marl at the base, and the Portsdown Marl at the top (Mortimore, 1986a). The chalk of this interval is typically very soft and flinty, the flints usually forming very large 'Potstones', one such being the Whitecliff Flint in the lower part of the succession. Weakly developed marls occur beneath the Whitecliff Flint, and locally on Portsdown (Downend Quarry [SU 601 067]), there is the anomalous development of a condensed succession of hardgrounds and phosphatic chalk (Mortimore, 1986a).
The fauna of the Whitecliff Beds includes an abundance of small macrofossils in the lower part (particularly bryozoans, serpulids and occasionally the micro-crinoid Applinocrinus cretaceus) continuing up from the Sompting Beds below. The belemnite Gonioteuthis becomes more frequent than in underlying intervals of the Culver Chalk Member (Mortimore, 1986a), and comminuted inoceramid shell is locally common.
Macrofossil Biozonation: upper A. cretaceus Subzone and post Applinocrinus Beds (sensu Christensen, 1991) (pars)
Correlation: see Correlation with other Southern Region Chalk Group classifications
see Correlation with other UK Chalk Group successions
References
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, hardground, Sompting Beds