First evidence for the Cenomanian–Turonian oceanic anoxic event (OAE2, ‘Bonarelli’ event) from the Ionian Zone, western continental Greece

Karakitsios, V. and Tsikos, Harilaos and Van Breugel, Y. and Koletti, L. and Sinninghe Damsté, J.S. and Jenkyns, H.C. (2007) First evidence for the Cenomanian–Turonian oceanic anoxic event (OAE2, ‘Bonarelli’ event) from the Ionian Zone, western continental Greece. International Journal of Earth Sciences, 96 (2). pp. 343-352. ISSN 1437-3254

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Official URL: http://dx.doi.org/10.1007/s00531-006-0096-4

Abstract

Integrated biostratigraphic (planktonic foraminifera, calcareous nannofossils), chemostratigraphic (bulk C and O isotopes) and compound-specific organic geochemical studies of a mid-Cretaceous pelagic carbonate—black shale succession of the Ionian Zone (western Greece), provide the first evidence for the Cenomanian–Turonian oceanic anoxic event (OAE2, ‘Bonarelli’ event) in mainland Greece. The event is manifested by the occurrence of a relatively thin (35 cm), yet exceptionally organic carbon-rich (44.5 wt% TOC), carbonate-free black shale, near the Cenomanian–Turonian boundary within the Vigla limestone formation (Berriasian–Turonian). Compared to the ‘Bonarelli’ black-shale interval from the type locality of OAE2 in Marche–Umbria, Italy, this black shale exhibits greatly reduced stratigraphic thickness, coupled with a considerable relative enrichment in TOC. Isotopically, enriched δ[superscript 13]C values for both bulk organic matter (−22.2‰) and specific organic compounds are up to 5‰ higher than those of underlying organic-rich strata of the Aptian-lower Albian Vigla Shale member, and thus compare very well with similar values of Cenomanian–Turonian black shale occurrences elsewhere. The relative predominance of bacterial hopanoids in the saturated, apolar lipid fraction of the OAE2 black shale of the Ionian Zone supports recent findings suggesting the abundance of N[subscript 2]-fixing cyanobacteria in Cretaceous oceans during the Cenomanian–Turonian and early Aptian oceanic anoxic events.

Item Type:Article
Additional Information:H.Tsikos, Department of Geology, Rhodes University, Grahamstown, South Africa. The original publication is available at www.springerlink.com
Uncontrolled Keywords:Cenomanian-Turonian; Cretaceous; Greece; Oceanic anoxic events (OAE); Stable isotopes; Stratigraphy
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Geology
ID Code:645
Deposited By: Mrs Eileen Shepherd
Deposited On:04 May 2007
Last Modified:01 Aug 2012 13:01
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