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Carbon-isotope stratigraphy recorded by the Cenomanian-Turonian Oceanic Anoxic Event; correlation and implications based on three key localities

H. Tsikos, H. C. Jenkyns, B. Walsworth-Bell, M. R. Petrizzo, A. Forster, S. Kolonic, Elisabetta Erba, I. Premoli Silva, M. Baas, T. Wagner and J. S. Sinninghe Damste
Carbon-isotope stratigraphy recorded by the Cenomanian-Turonian Oceanic Anoxic Event; correlation and implications based on three key localities (in Organic-carbon burial, climate change and ocean chemistry (Mesozoic-Palaeogene), Helen S. Morgans-Bell (prefacer) and Anthony S. Cohen (prefacer))
Journal of the Geological Society of London (July 2004) 161 (4): 711-719

Abstract

We present new, detailed carbon-isotope records for bulk carbonate, total organic carbon (TOC) and phytane from three key sections spanning the Cenomanian-Turonian boundary interval (Eastbourne, England; Gubbio, Italy; Tarfaya, Morocco), with the purpose of establishing a common chemostratigraphic framework for Oceanic Anoxic Event (OAE) 2. Isotope curves from all localities are characterized by a positive carbon-isotope excursion of c. 4ppm for TOC and phytane and c. 2.5ppm for carbonate, although diagenetic overprinting appears to have obliterated the primary carbonate carbon-isotope signal in at least part of the Tarfaya section. Stratigraphically, peak delta (super 13) C values for all components are followed by intervals of high, near-constant delta (super 13) C in the form of an isotopic plateau. Recognition of an unambiguous return to background delta (super 13) C values above the plateau is, however, contentious in all sections, hence no firm chemostratigraphic marker for the end-point of the positive isotopic excursion can be established. The stratigraphically consistent first appearance of the calcareous nannofossil Quadrum gartneri at or near the Cenomanian-Turonian boundary as established by ammonite stratigraphy, in conjunction with the end of the delta (super 13) C maximum characteristic of the isotopic plateau, provides a potentially powerful tool for delimiting the stratigraphic extent and duration of OAE 2. This Oceanic Anoxic Event is demonstrated to be largely, if not wholly, confined to the latest part of the Cenomanian stage.


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: 161
Serial Issue: 4
Title: Carbon-isotope stratigraphy recorded by the Cenomanian-Turonian Oceanic Anoxic Event; correlation and implications based on three key localities
Title: Organic-carbon burial, climate change and ocean chemistry (Mesozoic-Palaeogene)
Affiliation: Oxford University, Department of Earth Sciences, Oxford, United Kingdom
Affiliation: University of Oxford, Dept. of Earth Sciences, Oxford, United Kingdom
Pages: 711-719
Published: 200407
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 30
Accession Number: 2004-061342
Categories: StratigraphyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N37°45'00" - N38°30'00", W105°04'60" - W104°04'60"
Secondary Affiliation: Open University, GBR, United KingdomUniversita di Milano, ITA, ItalyRoyal Netherlands Institute of Sea Research, NLD, NetherlandsUniversity of Bremen, DEU, Federal Republic of Germany
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 200418
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