Cenozoic Foraminiferal and Dinoflagellate Cyst Biostratigraphy of the Central North Sea

Abstract

We present a detailed Cenozoic biostratigraphy for Paleogene bathyal and Neogene neritic strata, north of 55? in the central North Sea, and offshore mid-Norway, using both foraminifera and dinoflagellate cysts. Construction of the zonations was assisted by the quantitative stratigraphic methods RASC and STRATCOR. Eight Paleogene and four Neogene interval zones of benthic and some planktonic foraminifera are defined. These zones involve the average last occurrence of 64 taxa present in a minimum of 7 of 33 wells studied. Eighteen geographically rare, but stratigraphically important foraminifers and dinoflagellate cysts were inserted as "unique events". Thirteen Paleogene dinoflagellate cyst interval and peak zones are defined that are interrelated with the foraminiferal zonation. The Paleocene-Eocene boundary is assigned at the top of dinoflagellate cyst zone T2c (Apectodinium augustum LO), immediately above the upper limit of the Reticulophragmium paupera Zone. The Coscinodiscus Zone and dinoflagellate cyst zone T3A (acme of Deflandea oebisfeldensis) are earliest Eocene in age. Uppermost Eocene strata may be largely missing in the central North Sea, as is part or all of the Upper Miocene.

Evidences for a Paleocene marine incursion in southern Amazonia (Madre de Dios Sub-Andean Zone, Peru)

“…(MD-177; MD-184; MD-85; see Table 1 The agglutinated benthonic foraminifer Karreriella conversa (Eggerellidae), found in MD-208 255, has an Upper Cretaceous-Lutetian range ( Fig. 2; Gradstein et al, 1988;. 209…”

Oligocene deep-water agglutinated foraminifers at Site 985, Norwegian Basin, southern Norwegian Sea

“…During the early 1980s, several biostratigraphic schemes based on agglutinated foraminifers were devised for the Paleogene of the North Sea region (Gradstein and Berggren, 1981;King, 1983;Gradstein et al, 1988). It became apparent that a number of EoceneOligocene DWAF species occur throughout the North Sea, Norwegian Sea, and Labrador Sea, suggesting that they may be useful for correlation purposes throughout the northern part of the North Atlantic.…”

“…Subsequent studies have further refined the taxonomy and biostratigraphy of Norwegian Sea DWAF Kaminski et al, 1990;Osterman and Spiegler, 1996;Kaminski and Geroch, 1997;Nagy et al, in press;Gradstein and Kaminski, 1997). Quantitative studies of biostratigraphic data from 33 North Sea and Norwegian Sea exploration wells have yielded a refined biostratigraphic zonation of the area using DWAF and other microfossils (Gradstein et al, 1988;Gradstein et al, 1992Gradstein et al, , 1994Gradstein and Bäckström, 1996).…”

Site 801

“…Rare finds of Praecystammina globigerinaeformis in Paleocene sediments in Hole 801A extends the range of this species to the lowermost Tertiary in abyssal assemblages of low latitudes. Gradstein et al (1988) observed a very similar form, which they determined as Cystammina aff. globigeriniformis, in bathyal Paleocene wells of the central North Sea.…”