The Neogene - Quaternary boundary definition: a review and proposal

The problem of the Neogene/Quaternary (N/Q) boundary is examined in the light of the stratigraphic approach favoured by the International Stratigraphic Guide (HEDBERG, 1976) and in the ligth of the most recent advances in uppermost Pliocene-lower Pleistocene biostratigraphy. Based upon a critical review of the historical concepts of the Pliocene and Pleistecene epochs and upon the most recent data on the various N/Q boundary stratotypes proposed (Le Castella, Santa Maria di Catanzaro and Vrica) we consider that the Vrica Section is undoubtedly the most suitable for correctly defining the N/Q boundary. Regarding the precise definition of this boundary, it is proposed to the International Committees in charge of the problem that the N/Q boundary be defined in the Vrica Section by the lithological level of the first appearance of Cytheropteron testudo, because it represents a chronohorizon widely recognizable in the global geologic record and because it is the most historically appropriate