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IUGS ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma

Ratification par l’IUGS du Quaternaire en tant que système/période et du Pléistocène en tant que série/époque avec une base à 2.58 Ma
Philip L. Gibbard and Martin J. Head
p. 411-412

Abstracts

The International Union for Geological Sciences (IUGS) on 29 June, 2009 ratified a proposal by the International Commission on Stratigraphy that the base of the Quaternary System/Period and the base of the Pleistocene Series/Epoch be lowered to that of the Gelasian Stage/Age. The Gelasian is transferred accordingly from the Pliocene to the Pleistocene. The Global Stratotype Section and Point at Monte San Nicola, Sicily, Italy, with an estimated age of 2.58 Ma, defines the lower boundary of the Gelasian, Pleistocene and Quaternary. Details of the ratification are given, and implications discussed.

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We are grateful to Jim Ogg, former Secretary- General of the ICS and current Chair of its Subcommission on Stratigraphic Information, and Stan Finney, current Chair of the ICS, for their support and advice; and we appreciate the assistance of Jean‑Jacques Bahain in translating the Abstract.

1 - Announcement

1On 29 June 2009, the Executive Committee of the International Union for Geological Sciences (IUGS) approved, by majority vote, the 2 June 2009 recommendation of the International Commission on Stratigraphy (ICS) that:

2“1) the base of the Pleistocene Series/Epoch be lowered such that the Pleistocene includes the Gelasian Stage/Age and its base is defined by the Monte San Nicola GSSP, which also defines the base of the Gelasian; the base of the Quaternary System/Period, and thus the Neogene–Quaternary boundary, be formally defined by the Monte San Nicola GSSP and thus be coincident with the bases of the Pleistocene and Gelasian, and with these definitions, the Gelasian Stage/Age be transferred from the Pliocene Series/Epoch to the Pleistocene.” (Riccardi, 2009).

3Hence, the Global Stratotype Section and Point (GSSP) at Monte San Nicola in Sicily, Italy, which has served to define the base of the Gelasian Stage/Age since 1996 (Rio et al., 1998), now also defines both the base of the Pleistocene Series/Epoch and that of the Quaternary System/Period. The Gelasian GSSP has been correlated to Marine Isotope Stage (MIS 103) and is astrochronologically constrained at 2.58 Ma. The base of the Pleistocene had hitherto been defined by the GSSP at Vrica in Calabria, Italy, which is astrochronologically dated at 1.806 Ma (Lourens et al., 2005). This GSSP remains available to define the base of the Calabrian Stage formally (Cita et al., 2008).

2 - Discussion

4The ICS decision to approve the above proposal was reported in a June issue of Quaternaire (Gibbard and Head, 2009). The ICS presented this proposal to the IUGS Executive Committee for ratification, which was duly granted. Having now reported this important final decision, we clarify several issues relating to the boundary and to the ratification process.

51) The original Quaternary proposal submitted to the ICS for consideration (reproduced in Gibbard & Head, 2009, box 1) asserted that the GSSP of the Gelasian Stage coincides with the base of Marine Isotope Stage 103. This claim was based on information then published on the website of the ICS, but is incorrect. The GSSP of the Gelasian Stage does coincide with Marine Isotope Stage 103 (Rio et al., 1998), but not specifically its base.

62) Rio et al. (1998) stated that the Gelasian GSSP is at the base of a marly layer immediately overlying a sapropel (known as the Nicola bed) assigned to Mediterranean Precession-Related Sapropel (MPRS) 250. They noted that “The astrochronological age of sapropel MPRS 250 (mid-point), corresponding to precessional cycle 250 from the present, is 2.588 Ma (Lourens et al., 1996), which can be assumed as the age of the boundary.” (Rio et al., 1998, p. 85). Although an age of 2.588 Ma for the Gelasian GSSP (Rio et al., 1998, Lourens et al., 2005) has not since been disputed, it is not strictly correct, and without knowing the sedimentation rate of the sapropel, it is unrealistic to assign four signif- icant figures to the age. Thus, if we assume that the sapropel was deposited over 7–10 kyr (e.g. Capozzi et al., 2006) and its full thickness has been preserved, then the age of the GSSP rounds down to 2.58 Ma, a figure that we accept here. Ultimately, of course, the boundary is defined by the position of the GSSP in the rock record, not by its age or indeed any other criterion.

73) The Quaternary proposal submitted to the ICS in September 2008 had requested that “The Vrica GSSP (the present Quaternary and Pleistocene basal boundary) be retained as the base of the Calabrian Stage, the second stage of the revised Pleistocene Series.” (Gibbard and Head, 2009, p. 127). However, the ICS proposal to the IUGS omitted this request, due to oversight, and the IUGS ratification (above) made no mention of the Calabrian Stage. This stage, while meeting all necessary requirements (Cita et al., 2008) and having been accepted by both the ICS Subcommission on Quaternary Stratigraphy and the ICS itself, must therefore await future ratification by the IUGS.

8It is nonetheless evident that ratification by the IUGS Executive Committee formally brings to closure a debate on the status of the Quaternary and the position of the lower boundaries of both the Quaternary and the Pleistocene that has lasted for more than 60 years (Gibbard et al., 2009). Ratification by the IUGS is therefore a monumental event for the Quaternary community and beyond.

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Bibliography

CAPOZZI R., DINELLI E., NEGRI A. & PICOTTI V., 2006 - Productivity-generated annual laminae in mid-Pliocene sapropels deposited during precessionally forced periods of warmer Mediterranean climate. Palaeogeography, Palaeoclimatology, Palaeoecology, 235, 208-222.

CITA M.B., CAPRARO L., CIARANFI N., DI STEFANO E., LIRER F., MAIORANO P., MARINO M., RAFFI I., RIO D., SPROVIERI R., STEFANELLI S. & VAI G.B., 2008 – The Calabrian Stage redefined. Episodes, 31, 418-429.

GIBBARD P. & HEAD M.J., 2009 - The definition of the Quaternary System/Era and the Pleistocene Series/Epoch. Quaternaire, 20 (2), 125-133. [The title contains an error as it should refer to the Quaternary System/Period, not System/Era].

GIBBARD P.L., HEAD M.J., WALKER M.J.C. & the SUBCOMMISSION ON QUATERNARY STRATIGRAPHY, 2009 - Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma. Journal of Quaternary Science, 24: DOI: 10.1002/jqs. 1338.

LOURENS L.J., ANTONARAKOU A., HILGEN F.J., VAN HOOF A.A.M, VERGNAUD‑GRAZZINI C. & ZACHARIASSE W.J., 1996 - Evaluation of the Plio-Pleistocene astronomical timescale. Paleoceanography, 11, 391-413.

LOURENS L., HILGEN F., SHACKLETON N.J., LASKAR J. & WILSON D., 2005 - The Neogene Period. In F.M. Gradstein, J.G. Ogg and A.G. Smith (eds.), A Geologic Time Scale 2004. Cambridge University Press, Cambridge, 409-440 [Imprinted 2004].

RICCARDI A.C., 2009 - Letter from Prof. Alberto C. Riccardi, President, International Union of Geological Sciences, to Prof. Paul R. Bown, Secretary, International Commission on Stratigraphy, 30 June 2009.

RIO D., SPROVIERI R., CASTRADORI D. & DI STEFANO E., 1998 - The Gelasian Stage (Upper Pliocene): A new unit of the global standard chronostratigraphic scale. Episodes, 21, 82-87.

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References

Bibliographical reference

Philip L. Gibbard and Martin J. Head, « IUGS ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma », Quaternaire, vol. 20/4 | 2009, 411-412.

Electronic reference

Philip L. Gibbard and Martin J. Head, « IUGS ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma », Quaternaire [Online], vol. 20/4 | 2009, Online since 01 March 2012, connection on 19 June 2019. URL : http://journals.openedition.org/quaternaire/5289 ; DOI : 10.4000/quaternaire.5289

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About the authors

Philip L. Gibbard

Cambridge Quaternary, Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, England, U.K. Courriel: plg1@cam.ac.uk

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Martin J. Head

Department of Earth Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario L2S 3A1, Canada. Courriel: mjhead@brocku.ca

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