The Calabrian Stage redefined

The name Calabrian was introduced in the geological literature by the French stratigrapher Maurice Gignoux in 1910, and later described in his important monograph (633 pages) “Les formations marines pliocènes et quaternaires de l'Italie du sud et de la Sicile” published in 1913. Detailed data were provided on several sections (Santa Maria di Catanzaro, Caraffa, Monasterace, Palermo) and on their fossil content. The Calabrian Stage has commonly been used for over fifty years as the oldest subdivision of the Quaternary, notably in the time scales of Berggren & van Couvering (1974) and Haq & Eysinga (1987). However, after the GSSP for the Pliocene/Pleistocene boundary (P/P) was approved by INQUA in 1982 and ratified by IUGS in 1984 at the Vrica section of Calabria, there was a decline in the usage of the stage name, and an increasing tendency by many Quaternary workers to question the boundary stratotype. This was because there was increasing evidence that it did not correspond to the beginning of the “ice age”. In doing so, they were not complying with the recommendations presented at the 18th International Geological Congress (IGC) in London, 1948 (Oakley, 1950). The purpose of this paper is to clarify the current definition and usage of the Calabrian Stage, with a proper historical background and the presentation of several marine fossiliferous sections exposed on land that can be chronostratigraphically correlated with multiple criteria including biostratigraphy, magnetostratigraphy, isotopic stratigraphy, “astrocyclostratigraphy” and occasionally tephrastratigraphy. Other sections considered and equated with those from land are from the Mediterranean deep-sea record (Tyrrhenian Sea ODP Site 653, Ionian Sea ODP Site 964, Levantine Sea ODP Site 967, Balearic Sea ODP 975). The Calabrian Stage has a duration of approximately 1.1 Ma. Its base occurs in the latest part of the Olduvai Event; its top is coincident with the base of the following Ionian Stage. After a general agreement, the definition of the base of the Ionian Stage (in progress) will be proposed coincident with the Brunhes/Matuyama magnetic reversal. The choice of a physical parameter as a leading criterion for its identification facilitates its recognition in continental successions.