Original paper

Proposition d'une échelle stratigraphique standard pour le Paléogène

Cavelier, Claude; Pomerol, Charles

Newsletters on Stratigraphy Volume 6 Number 1 (1977), p. 56 - 65

10 references

published: Mar 15, 1977

DOI: 10.1127/nos/6/1977/56

BibTeX file

ArtNo. ESP026000601016, Price: 29.00 €

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Le grand nombre d'étages régionaux aux stratotypes mal ou insuffisamment définis dans l'échelle stratigraphique du Paléogène est une source de confusion et alimente depuis plus d'un siècle des discussions stériles. Une première tentative de normalisation a été tentée en 1974 à propos du contenu de l'Ilerdien et de la position de la limite Paléocène-Eocène en Mésogée. Une autre importante contribution qui concerne la limite Eocène-Oligocène vient d'être présentée dans le thèse de CAVELIER avec pour corollaire la discussion sur la position relative du Bartonien et du Priabonien. Ces deux étages ne sont pas équivalents comme on l'admet généralement. Les corrélations foundées principalement sur les Mammifères, les Mollusques et le Nannoplankton montrent en effect que le Priabonien ne correspond qu'à la partie supérieure (Ludien) du Bartonien s. l. D'autre part, la discussion reste ouverte sur la limite Eocène moyen-Eocène supérieur (à la base du Bartonien, comme c'est l'usage en Europe septentrionale, ou à la base du Priabonien comme on l'admet implicitement en Mésogée) ainsi que sur la limite Oligocène-Miocène.


The large number of regional stages with poorly or insufficiently defined stratotypes in the stratigraphic scale of the Paleogene is a source of confusion and has contributed to sterile discussions for more than a century. A first effort at standardization, attempted in 1974, concerned the contents of the Ilerdian and the position of the Paleocene-Eocene boundary in the Mesogean area. Another important contribution, treating the Eocene-Oligocene boundary, has just been presented by CAVELIER and has as a corollary a discussion of the relative position of the Bartonian and the Priabonian. These two stages are not equivalents as has been generally thought. Correlations based principally on mammals, molluscs and nannoplankton demonstrate that the Priabonian corresponds only to the upper part (Ludian) of the Bartonian s. l. The considerations which have let us to propose the subdivisions presented on the table 1 are the following: - the choice of stratotypes belonging only at the marine domain, enclosing stratigraphically useful fossils; - the possibility for each of them to define stratotypic, parastratotypic, or hypostratotypic limits in continuous series of the Mesogean region (in particular in Spain and Italy); - respect, as much as possible, traditions consacrated by usage. The correlation of these stages with those used in other regions of the globe is founded on the biozones and on isotopic ages figured on table 1. However, the authors would like to point out the following facts: 1. The specific determination of microorganisms is sometime uncertain. 2. Most pelagic organisms are affected by ecologic conditions and are fiable only in a particular climatic domain. 3. The scales based on spores and pollen, dinoflagellates, charophytes and mammals, under study, are not yet mentioned. 4. Isotopic ages should be considered with prudence (because uncertainty as to the exact value and the constancy of the decay, and of occasionally delicate interpretations). On the other hand, the discussion remains open on the middle Eocene-late Eocene boundary (it can be placed either at the base of the Bartonian, as in usual in Northern Europe, or at the base of the Priabonian, as is implicitely done in the Mesogean region) and on the Oligocene-Miocene boundary.