Cretaceous nannofossil biozones of the brazilian continental margin: problems and possible solutions

Abstract

In this paper, each one of the twelve nannofossil zones that were proposed, up to the present date, undergoes a criticaI analysis, and their positive and negative aspects are discussed. In addition, other biological events are presented and they may be used in order to refine the sections. It is also presented a hypothetical biostratigraphical framework with an attempt to cover ali nuances and peculiarities observed in the investigated basins. This framework stiet! be tested, if accomplishable, it shall guide future studies.