Chronostratigraphy of the Chalk Group - Maastrichtian Stage

This stage was first defined by Dumont (1850), based on the area around Maastricht in the Netherlands (Birkelund et al., 1984).

Definition of base of stage

The first appearance of the belemnite genus Belemnella (Birkelund et al., 1984), but this is difficult to precisely identify in UK successions, where a better criterion is the acme of the foraminiferan Reussella szajnochae (Bailey et al., 1984). Burnett et al. (1992) pointed out that the alleged synchroneity of micro-fossil and macro-fossil events across the Campanian / Maastrichtian boundary is false. Micro-fossil indices for the basal Maastrichtian occur below macrofossil indices for the same horizon.

Constituent Chalk Group lithostratigraphical units in the UK

East Anglia: Sidestrand Chalk Member, Trimingham Sponge Beds Member, Little Marl Point Member, Beacon Hill Grey Chalk Member

N. Ireland: Tanderagee Chalk Member, Port Calliagh Chalk Member, Ballycastle Chalk Member

North Sea: Mackerel Formation (pars), Tor Formation

Constituent macrofossil biozones in the UK (onshore)

	younger Maastrichtian macrofossil biozones not preserved onshore in the UK
MAASTRICHTIAN	B.occidentalis (pars)
	B.lanceolata s.l.

Lithostratigraphical marker-beds for the base of the stage

East Anglia: not precisely defined, owing to lack of continuous exposure; the highest exposed Campanian is marked by the Overstrand Pyramidata Hardground in north Norfolk.

N. Ireland: the Long Gilbert Flint

References

BAILEY, H W, GALE, A S, MORTIMORE, R N, SWIECICKI, A & WOOD, C J. 1984. Biostratigraphical criteria for the recognition of the Coniacian - Maastrichtian stage boundaries in the Chalk of north-west Europe, with particular reference to southern England. Bulletin of the Geological Society of Denmark, Vol. 33, 31 - 39.

BURNETT, J A, HANCOCK, J M, KENNEDY, W J & LORD, A R. Macrofossil, planktonic foraminiferal and nannofossil zonation at the Campanian / Maastrichtian boundary. Newsletters on stratigraphy, 27, 157-172

BIRKELUND, T, HANCOCK, J M, HART, M B, RAWSON, P F, REMANE, J, ROBASZYNSKI, F, SCHMID, F, SURLYK, F. 1984. Cretaceous stage boundaries - Proposals. Bulletin of the Geological Society of Denmark, 33, 3-20.

Dumont, A. 1850. Rapport sur la carte geologique de royaume. Acad. Roy. Sci. Lettres, Beaux-Arts, Belgique Bull, 16, 351-373.