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Journal of Micropalaeontology An open-access journal of The Micropalaeontological Society
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Volume 19, issue 1
J. Micropalaeontol., 19, 69–84, 2000
https://doi.org/10.1144/jm.19.1.69
© Author(s) 2000. This work is distributed under
the Creative Commons Attribution 4.0 License.
J. Micropalaeontol., 19, 69–84, 2000
https://doi.org/10.1144/jm.19.1.69
© Author(s) 2000. This work is distributed under
the Creative Commons Attribution 4.0 License.

  01 May 2000

01 May 2000

Trans-Atlantic dinoflagellate cyst stratigraphy across the Cenomanian–Turonian (Cretaceous) Stage boundary

Paul Dodsworth Paul Dodsworth
  • Centre for Palynology, Dainton Building, University of Sheffield, Sheffield S3 7HF, UK

Abstract. The principal palynological proxy for the Cenomanian–Turonian Stage boundary, the top of consistent/common Litosphaeridium siphoniphorum (a dinoflagellate cyst), occurs in Greenhorn Bed 73 at the international stratotype section, west of Pueblo, Colorado, USA. This datum occurs in the same position, as indicated by planktonic foraminifera (a few beds higher than the range top of R. cushmani), ammonites (upper part of the S. gracile/M. geslinianum Zone) and geochemistry (immediately below maximum δ13C values), at Pueblo (Western Interior Basin) and localities in southern England (Wessex–Paris Basin) and northern Germany (Lower Saxony Basin). Of over 100 dinoflagellate cyst taxa recorded from Pueblo and a correlative section at Lulworth, southern England, possibly as few as six do not range into the Turonian. In the uppermost Cenomanian – lowermost Turonian succession at Pueblo, there are no consistent absences of any common taxa (with four exceptions) and there is no evidence for a collapse in cyst-forming dinoflagellate populations during the Cenomanian–Turonian boundary mass extinction interval/‘oceanic anoxic event’. However, the composition of palynological assemblages from the Upper Cenomanian appears to reflect palaeoenvironmental stress and/or an increase in the supply of land-derived and relatively nearshore palynomorphs.

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