Cenomanian 3

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This sequence is approximately coextensive with the M. dixoni Zone. The base is a silty marl containing glauconite and phosphatised intraclasts (= M4 marker of Gale, 1989) resting on a burrowed erosion surface (Robaszynski et al., 1998). The erosion surface is interpreted as a sequence boundary, and the overlying silty bed represents a transgressive lag at the base of a transgressive systems tract. An increase in carbonate content at the level of the B11/12 couplets (see: Cyclostratigraphy of the Chalk Group) of Gale (1995) represents a maximum flooding surface, and the overlying succession, containing an acme of Inoceramus virgatus surmounted by the lowest of three acmes of Orbirhynchia mantelliana, represents a highstand (Gale et al., 1999). The top of the sequence falls just below the top of the M. dixoni Zone.

References[edit]

GALE, A S. 1989. Field meeting at Folkestone Warren, 29th November, 1987. Proceedings of the Geologists' Association, 100, 73-82.

GALE, A S. 1995. Cyclostratigraphy and correlation of the Cenomanian Stage in Western Europe. In HOUSE, M R & GALE, A S (eds.), Orbital Forcing Timescales and Cyclostratigraphy, Geological Society Special Publication, No. 85, pp. 177-197.

GALE, A S, HANCOCK, J M & KENNEDY, W J. 1999. Biostratigraphical and sequence correlation of the Cenomanian successions in Mangyshlak (W. Kazakhstan) and Crimea (Ukraine) with those in southern England. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, 69, 67-86.

ROBASZYNSKI, F, GALE, A, JUIGNET, P, AMÉDRO, F, HARDENBOL, J. 1998. Sequence stratigraphy in the Upper Cretaceous series of the Anglo-Paris Basin: exemplified by the Cenomanian stage. Society of Economic Paleontologists and Mineralogists, Special Publication No. 60, 363-386.