Lower pleistocene dinoflagellate cyst, foraminiferal and pollen assemblages in four boreholes in the Southern North Sea

Abstract

Neogene and Lower Pleistocene stratigraphy in the Southern North Sea has been investigated in four I.G.S. boreholes between East Anglia and the Netherlands. The foraminifera of the Red Crag Formation in Borehole 81/51 are closely similar to Upper Pliocene assemblages in Holland. The overlying succession is clearly punctuated by unconformities in seismic profiles, separating four early Pleistocene formations in the boreholes, and indicating intervals of significant stratigraphic hiatus offshore. The Westkapelle Ground and Smith's Knoll Formations correlate with Thurnian and Antian Stage deposits in East Anglia. Pollen spectra in the Winterton Shoal and Yarmouth Roads Formations are similar to Baventian and Bramertonian assemblages in Britain. The autochthonous marine and allochthonous terrestrial microfauna and flora provide conflicting evidence of early Pleistocene palaeoclimate. The dinoflagellate cysts and foraminifera indicate that each formation was deposited in a warm temperate neritic environment. The pollen record, containing evidence of fluctuation between boreal and mixed coniferous-deciduous regional forest cover, suggests alternation between cool and warm temperate palaeoclimate.

Lower Pleistocene deltaic and marine sediments in boreholes from the central North Sea

“…Sangree and Widmier, 1977). This sequence has been broadly correlated with the Lower Pleistocene succession in the southern North Sea which displays many of the sedimentological and seismic characteristics of delta-related sedimentation (Cameron et al, 1984(Cameron et al, , 1987Balson and Cameron, 1985). An overall vertical and lateral transition from marine to non-marine facies is attributed to delta expansion across a shallow, open shelf marine environment due to a massive influx of sediment into the basin during the early Pleistocene.…”

“…Lower Pleistocene sediments may have originally extended much further to the west than their present distribution suggests, having been removed by later erosional events. Detailed information on the Lower Pleistocene deposits is currently restricted to the southern North Sea where open shelf marine and delta-related sediments have been identified (Cameron et al, 1984). The purpose of this paper is to describe Lower Pleistocene sediments from the central North Sea in the light of the southern North Sea interpretation.…”

The Lower Pleistocene stratigraphy of the Ormesby Borehole, Norfolk, England

“…The Red Crag Formation cyst flora (Cameron et al 1984) is comparable to units C and D in its lack of 0. israelianum and higher proportions of Protoperidinium spp. ; the Westkapelle Ground Formation with units E to G (Fig.…”

“…There are few dinoflagellate data available from the Lower Pleistocene of the British Isles (Wall & Dale, 1968;Cameron et al 1984). The succession at Ormesby has allowed the first detailed dinoflagellate cyst analysis of the Lower Pleistocene sediments from East Anglia.…”

“…multiplexum; and finally the Smiths Knoll Formation with sediments younger than unit G with high percentages of Spiniferites spp. (Cameron et al 1984).…”