The Aptian Stage: Back to fundamentals
Abstract
The original definitions of the Aptian, Albian and Urgonian stages by d'Orbigny (1840, 1842, 1847, respectively) on the basis of lithological and paleonto-logical criteria were sufficiently clear and should not have generated the misinterpretations and confusion that began at the end of the 19th century and continue today. The purpose of this paper is thus to clarify the succession of stages within this period of the Cretaceous as well as their relationships, by a better respect for the thought of their creator and also in light of recent work on the historical stratotypes. This return to fundamentals leads us to propose the insertion of a Bedoulian stage between the Barremian (ex Urgonian) and the Aptian s.s. Our proposal includes also recommendations for the definition of the Barremian, Bedoulian (sensu novo), Aptian (s. s.) and Albian boundaries and the corresponding Global Boundary Stratotype Sections and Points (GSSP).