A brief review of the Late Cretaceous “Oceanic Red Beds” of the North Sea offshore region

https://doi.org/10.1016/j.pgeola.2020.01.006Get rights and content

Abstract

Late Cretaceous red chalk units of “deep” marine origin were recognised and published from the North Sea Basin almost thirty years ago (King et al., 1989), however it is only now that we are beginning to recognise their oceanographic, depositional and climatic significance. Their stratigraphic occurrence is redefined and an additional red unit is proposed. The palaeoceanographic implications of these red units are considered in the light of recent studies on the origins and occurrences of Cretaceous Oceanic Red Beds (CORB’s) and of the red horizons in the onshore Cretaceous Chalk of North West Europe.

Introduction

As early as 1976 Chris King, working then for Paleoservices Ltd., had noted the existence of red argillaceous carbonate units (“marls”) within the Late Cretaceous sequence of the Outer Moray Firth area of the U.K. North Sea offshore (see Fig. 1). This work was part of a proprietary study of hydrocarbon exploration wells drilled around the Buchan High structure which lies predominantly within Block 21/1 in the Outer Moray Firth (see Fig. 1 for the location of this field, from Benzagouta et al., 2001). The significance and origin of these deposits was certainly not recognised at the time, but their persistence in numerous wells in the region gave rise to their inclusion in numerous unpublished proprietary zonation schemes which were in restricted circulation during the late 1970’s – early 1980’s.

Early attempts to synthesise some of the micropalaeontological and biostratigraphical studies were being actively carried out in the U.K. during this time and these resulted in a number of key publications, notably the two editions of the Stratigraphic Atlas of Fossil Foraminifera (eds., Jenkins and Murray, 1981;1989). The first edition of the Stratigraphic Atlas included an early paper on the North Sea Cainozoic (King et al., 1981) and this was followed by a further detailed paper on the Cainozoic published by the B.G.S. (King, 1983), but at this time no attempt had been made to publish any existing zonal schemes for the Cretaceous succession, largely due to commercial confidentiality. The publication of the second edition of the Stratigraphic Atlas (Jenkins and Murray, 1989) created the opportunity for a break with commercial sensitivities and the Cretaceous of the North Sea chapter (King et al., 1989) was a milestone in bringing to a wider audience the detailed micropalaeontological data which existed in the commercial sector for the North Sea succession. Only recently, with the publication of the “Stratigraphic Guide to the Cromer Knoll, Shetland and Chalk Groups of the North Sea and Norwegian Sea” by Gradstein and Waters (2016) has there been a comprehensive review of this part of the stratigraphic succession.

King et al. (1989) recognised depth related biofacies variations through the North Sea region during the Cretaceous by defining discrete “northern” (FCN) and “southern” (FCS) zonal schemes for the outer sublittoral to bathyal ‘Shetland’ facies and southern North Sea ‘shelf’ facies respectively. In the Outer Moray Firth area (King et al., 1989, fig. 8.4.) there was also recognised for the first time, the existence of a threefold series of Upper, Middle and Lower Red Units within the Chalk Group, with the ‘Upper Red Unit’ extending into the Central North Sea area, denoted as time equivalent ‘Pink Chalks’ (see Fig. 2). These red units were not recognised in the southern North Sea region and there was no real discussion of their origin, although King et al. (1989) noted that “some units are red or brown. They were deposited mainly during high eustatic sea levels”. This comment pertains primarily to red beds in the Early Cretaceous succession, although they also note the red staining of foraminifera derived from the ‘Upper Red Unit’ at the top of the Flounder Formation.

The ‘Middle Red Unit’ and ‘Lower Red Unit’ receive little further note in the King et al. (1989) publication, but they are located stratigraphically within the lower Late – upper Middle Santonian and Coniacian respectively in their Figure 8.4. The subsequent publication of the Lithostratigraphic nomenclature of the UK North Sea; Cretaceous of the Central and Northern North Sea (Johnson and Lott, 1993) acknowledges the presence of red and pink stained chalks at the top of both the time equivalent Mackerel and Flounder formations as well as within the lower part (J1) of the Jorsalfare Formation. Johnson and Lott (1993) also acknowledge the record of three red units within the Flounder Formation and they also note the presence of three argillaceous units within the Mackerel Formation, each with a distinctly raised gamma log response, although the colour of these units is not indicated.

Section snippets

Constraining the Age of the North Sea Red Units within the Late Cretaceous

In order to place the Red Units into stratigraphic context they have been superimposed onto a standard stratigraphic zonation scheme for the Central North Sea region modified from Fritsen et al. (1999) (see Fig. 3).

The origin of Late Cretaceous Oceanic Red Beds in the North Sea Basin

In order to produce red beds in deep or shallow water, fine grained, carbonate deposits require the preservation of the originally ferric oxidised state of any detrital iron hydroxide or hydrated oxides (responsible for the red pigment) during diagenesis. Under normal diagenetic conditions the Chalk sediment, with its low organic content, would have passed from the zone of oxic into the zone of anoxic diagenesis, where any ferric iron hydroxides and hydrated oxides would have been reduced with

Conclusions

King et al. (1989) recorded the existence of three red chalk units within the Late Cretaceous deep water succession of the North Sea Basin. They noted that the geographical extent of these red units was limited to the Northern and Central Grabens and the Outer Moray Firth of the North Sea. These red levels are not identified in the southern North Sea, to the south of the mid North Sea or Rinkøbing-Fyn High or in any of the onshore Chalk sections in adjacent areas of northern Europe. They do not

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This paper was originally presented at the “celebration” event organised to recognise the contribution made by Dr. Chris King to the stratigraphy of the British Isles and the adjacent offshore areas, so the author acknowledges that without Chris King this work would not have been possible. In addition, thanks go to Chris Jeans for his additional information regarding the geochemistry of red chalks and to Matt Hampton for his helpful comments regarding the structuring of the text. The anonymous

References (35)

  • S. Neuhuber et al.

    Turonian oceanic red beds in the Eastern Alps: Concepts for paleoceanographic changes in the Mediterranean Tethys

    Palaeogeography, Palaeoclimatology, Palaeoecology

    (2007)
  • N.R. Ainsworth et al.

    An Early Cretaceous lithostratigraphic and biostratigraphic framework for the Britannia Field reservoir (Late Barremian - Late Aptian), U.K. North Sea

    Petroleum Geoscience

    (2000)
  • F.T. Banner et al.

    Barremian-Aptian Praehedbergellidae of the North Sea area: a reconnaissance

    Bulletin of the Natural History Museum

    (1993)
  • M.S. Benzagouta et al.

    Reservoir heterogeneities, in fractured fluvial reservoirs of the Buchan Oilfield (Central North Sea)

    Oil and Gas Science and Technology, Review IFP

    (2001)
  • N.P. Bramwell et al.

    Chalk exploration, the search for a subtle trap

  • J.A. Burnett et al.

    Upper Cretaceous

  • S. Crittenden

    The distribution of Palaeogene planktonic foraminifera and the biostratigraphy of a borehole in the southern North Sea

    Newsletters on Stratigraphy

    (1981)
  • S. Crittenden et al.

    The Early to “Middle” Cretaceous lithostratigraphy or the Central North Sea (U.K. Sector)

    Journal of Petroleum Geology

    (1991)
  • J. Engelke et al.

    Tracking Late Cretaceous environmental change: Geochemical environment of the upper Campanian to lower Maastrichtian chalks at Kronsmoor, northern Germany

    Cretaceous Research

    (2017)
  • G. Ernst et al.

    Event-stratigraphie im Cenoman und Turon von NW-Deutschland

    Zitteliana

    (1983)
  • A. Fritsen et al.

    A Joint Chalk Stratigraphic Framework

    (1999)
  • F.M. Gradstein et al.

    Stratigraphic Guide to the Cromer Knoll

    (2016)
  • M.J. Hampton et al.

    A Holostratigraphic approach to the chalk of the North Sea Eldfisk Field, Norway

  • J.M. Hancock

    The petrology of the Chalk

    Proceedings of the Geologists’ Association

    (1976)
  • M.B. Hart

    Late Cretaceous climates and foraminiferid distribution

  • M.B. Hart et al.

    Cretaceous

  • W.W. Hay

    Cretaceous oceans and ocean modelling

  • 1

    Formerly: Network Stratigraphic Consulting Ltd., Harvest House, Cranborne Road, Potters Bar, Hertfordshire, EN6 3JF.

    View full text