Thuoux and Saint-Pierre d'Argençon sections (Subalpine Basin, southeastern France): case studies of ammonite biostratigraphy for the potential candidate Callovian-Oxfordian GSSP.
Résumé
The Thuoux and Saint-Pierre d'Argençon sections (Subalpine Basin, southeastern France) display a thick silty-clayey sedimentation with abundant and diversified ammonite faunas, free of detectable hiatuses. The Callovian-Oxfordian boundary is biostratigraphically located between the Lamberti and the Mariae zones or, more precisely, between the Lamberti Subzone (paucicostatum horizon) and the Scarburgense Subzone (thuouxensis horizon). The mixing of Boreal-Sub-Boreal Cardioceratinae and Sub-Mediterranean-Tethyan Hecticoceratinae, Peltoceratinae, and Perisphinctinae in this basin allows reliable worldwide correlations that enhance the choice of the Thuoux and Saint-Pierre d'Argençon sections as a Callovian-Oxfordian GSSP candidate.