The carbon-isotope record of three sections of shallow-water carbonates from the Upper Cretaceous sequences of the southern Apennines (Italy) shows a pronounced positive excursion of about 4–5‰. Using the upper Cenomanian Cisalveolina fraasi level as a biostratigraphic tie-point we correlate this excursion to the OAE-2 isotopic event. Comparison with the standard reference 13C curve of Eastbourne (England) shows that the overall character of the excursion is clearly reproduced in the shallow-water curves. Chemostratigraphic correlation allows definition of the age of some important shallow-water biostratigraphic events to the precision of an ammonite zone, using the well-established bio-chronostratigraphic framework defined in the Eastbourne section. The onset of the Cenomanian–Turonian isotopic excursion coincides with a transgressive trend, recorded by the occurrence of more open-marine facies and culminating with an incipient drowning in one of the sections studied. Our data suggest that the open-ocean isotopic signal is most faithfully recorded and preserved in shallow-water platform carbonates during transgressive periods, when the effects of meteoric diagenesis and seawater ageing are less severe.
Carbon-isotope stratigraphy of Cenomanian-Turonian platform carbonates from the southern Apennines (Italy): a chemostratigraphic approach to the problem of correlation between shallow-water and deep-water successions / Parente, Mariano; G., Frijia; M., DI LUCIA. - In: JOURNAL OF THE GEOLOGICAL SOCIETY. - ISSN 0016-7649. - STAMPA. - 164:(2007), pp. 609-620. [10.1144/0016-76492006-010]
Carbon-isotope stratigraphy of Cenomanian-Turonian platform carbonates from the southern Apennines (Italy): a chemostratigraphic approach to the problem of correlation between shallow-water and deep-water successions
PARENTE, MARIANO;
2007
Abstract
The carbon-isotope record of three sections of shallow-water carbonates from the Upper Cretaceous sequences of the southern Apennines (Italy) shows a pronounced positive excursion of about 4–5‰. Using the upper Cenomanian Cisalveolina fraasi level as a biostratigraphic tie-point we correlate this excursion to the OAE-2 isotopic event. Comparison with the standard reference 13C curve of Eastbourne (England) shows that the overall character of the excursion is clearly reproduced in the shallow-water curves. Chemostratigraphic correlation allows definition of the age of some important shallow-water biostratigraphic events to the precision of an ammonite zone, using the well-established bio-chronostratigraphic framework defined in the Eastbourne section. The onset of the Cenomanian–Turonian isotopic excursion coincides with a transgressive trend, recorded by the occurrence of more open-marine facies and culminating with an incipient drowning in one of the sections studied. Our data suggest that the open-ocean isotopic signal is most faithfully recorded and preserved in shallow-water platform carbonates during transgressive periods, when the effects of meteoric diagenesis and seawater ageing are less severe.File | Dimensione | Formato | |
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