Contribution
Age constraint of the Cenomanian (Late Cretaceous) Fossillagerstätte of Hjoûla (Lebanon) based on ammonites
Lehmann, Jens; Bornemann, André; Jattiot, Romain; Nohra, Roy; Resch, Udo
Newsletters on Stratigraphy Volume 57 Number 2 (2024), p. 203 - 223
115 références bibliographiques
publié: Apr 22, 2024
publication en ligne: Feb 1, 2024
manuscrit accepté: Nov 21, 2023
révision final du manuscrit reçu: Nov 21, 2023
révision du manuscrit demandée: Nov 1, 2023
manuscrit reçu: Sep 20, 2023
ArtNo. ESP026005702004, Prix: 29.00 €
Abstract
The Upper Cretaceous (Cenomanian) laminated limestones of Lebanon are among the most productive Cretaceous Fossillagerstätten in the world, but their geological age is poorly constrained. Ammonites only occur at the famous Hjoûla site, but they are usually too poorly preserved for identification. Here we present the first biostratigraphical dating at the zonal level based on well-preserved specimens. Eucalycoceras rowei and Eucalycoceras cf. pentagonum indicate a correlation with the lower upper Cenomanian, Calycoceras (Proeucalycoceras) guerangeri Zone, of western Europe. We also record Euomphaloceras varicostatum and Forbesiceras aff. baylissi, E. varicostatum constitutes the first record out of India and F. baylissi is a rare species that is hitherto only recorded from the lower and possibly middle Cenomanian. We also investigated calcareous nannofossils of the samples taken from the matrix of the ammonites. Corollithion kennedyi (base NC10B) unequivocally supports a Cenomanian age, whereas other Cenomanian marker species have not been identified. Preservation appears a major factor in controlling the assemblage composition, and is, thus, hampering a detailed nannofossil biostratigraphy.
Mots-clefs
Ammonites • Upper Cretaceous • upper Cenomanian • Lebanon • biostratigraphy