Cainozoic biostratigraphy and palaeobathymetry, northern North Sea and Haltenbanken
pp. 3-32

This study details the biostratigraphy and palaeobathymetry of Palaeogene bathyal and Neogene neritic strata in the North Sea and on Haltenbanken, using the 'tops' or last common presence of 190 benthic and planktonic foraminifers, dinoftagellates, and miscellaneous microfossils in 26 wells. Mathematical and graphical sequencing methods assisted with definition of the zones, and with the most likely order of the microfossil events within each zone. The interval zones are: Zone NSR 13 - Cassidulina teretis, Pleistocene; Zone NSRI2B - Cibicidoides grossa, late Pliocene; Zone NSRI2A -Monspeliensis pseudotepida, early (part of) Late Pliocene; Zone NSRII - Neogloboquadrina atlantica, Early Pliocene; Zone NSRIO - Bo/boforma metzmacheri, Late Miocene; Zone NSR9B -Martinotiella cylindrica, late Middle to early Late Miocene; Zone NSR9A - Globorotalia praescitula gr., late Early to early Middle Miocene; Zone NSR8B - unnamed, Early Miocene; Zone NSR8A - Globigerina ex. gr. officinalis, Late Oligocene (Chattian); Zone NSR7B - Turrilina alsatica, Early Oligocene to early Late Oligocene; Zone NSR7A - Adercotryma agterbergi, Early Oligocene (Rupelian); Zone NSR6B - Globorotalia cerroazulensis, Late Eocene (Priabonian); Zone NSR6A - Reticulophragmium amp/ectens, late Middle Eocene (Bartonian); Zone NSRSB - Ammomarginu/ina aubertae, early Middle Eocene (Lutetian); Zone NSRSA - Reticulophragmium intermedia, late Early to early Middle Eocene; Zone NSR4 - Subbotina patagonica, Early Eocene (Ypresian); Zone NSR3 - Coscinodiscus spp., earliest Eocene; Zone NSR2B - Reticulophragmium paupera, Late Palaeocene (Selandian); Zone NSR2A - Trochammina ruthvenmurrayi, early Late Palaeocene; Zone NSRI - Subbotina pseudobulloides, Early Palaeocene (Danian). Range charts give details of the stratigraphic extent of 140 foraminifers and other shelly microfossil taxa. The zonation is correlated to a seismic sequence stratigraphy with 14 depositional units. Palaeoecological analysis reveals five foraminiferal assemblages, which characterize inner shelf through middle slope (bathyal) depth regimes. The upper Oligocene-lower Miocene siliceous biofacies on Tampen Spur is thought to reftect slope upwelling. Upper Eocene strata appear to be largely missing in the central North Sea, as is part or all of the Upper Miocene.

F.M. Gradstein1,2 & S. A. Bäckström1, 1 Saga Petroleum, Kjørboveien 16, N-1301 Sandvika, Norway; 2 Geologica/ Survey of Canada, P.O. Box 1006, Dartmouth, N.S., Canada.