Revision of the Geological Time Scale; Implications for the "Quaternary"
Posted by John J. Clague 08 Jul 2004 11:55:00
Revision of the Geological Time Scale; Implications for the "Quaternary"
The International Commission on Stratigraphy (ICS) intends to extend the Neogene System to the present and eliminate Quaternary as a formal chronostratigraphic
unit in the new Geological Time Scale. Brad Pillans, President of the INQUA Commission on Stratigraphy and Chronology, has made a proposal to ICS and
INQUA to redefine the Quaternary as a Subsystem of the new Neogene System. Dr. Pillans' proposal has been circulated to INQUA members and the larger
community of earth scientists interested in the late Cenozoic and is included in next issue of Quaternary Perspectives. An alternative position, advocating that we
stand our ground and demand that the Quatenary be retained as a System separate and distinct from the Neogene, is presented in the same issue by Phil Gibbard,
Chair of the ICS Subcommission on Quaternary Stratigraphy.
The INQUA Executive Committee is concerned that ICS has not consulted representatives of the Quaternary community about its changes to the late Cenozoic
part of the time scale. It would be prudent for ICS to defer any changes to the "Quaternary" until the Quaternary community has had time to more fully considered
options and consequences. Consultation is in progress and will continue, with INQUA's support, at IGC in Florence this summer and at the next INQUA Congress
in Cairns, Australia, in 2007.
The INQUA Executive Committee asks that consider it's formal position on this important issue and the similar position of the International Association of
Geomorphologists (IAG), both of which are given below. Please express your views to the ICS Chairman (Felix Gradstein, felix.gradstein@nhm.uio.no) and
Secretary General (James Ogg, jogg@purdue.edu), with a copy to John Clague, President of INQUA (jclague@sfu.ca).
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The following is the position of the INQUA Executive Committee on the proposed revision of the Geological Time Scale.
INQUA insists that "Quaternary" be retained as a formal unit in the new Geological Time Scale. The Quaternary is in some respects the most important
period in earth history, a time of major climatic, oceanographic, and biotic changes, and the appearance and evolution of the human species. Its importance is
reflected in the fact that it has a strong interdisciplinary union (INQUA), that it is appreciated by scientists outside of the geological sciences, and that it is a
doorway through which new approaches and ideas are introduced into geology. "Quaternary" is too important a term to be removed simply because it is may make
the geological time scale tidier (the "Primary" and "Secondary" having been eliminated long ago, and the Tertiary shortly to follow). "Quaternary" is the bridge
between humans and geology, and it provides an umbrella for bringing other important and fundable disciplines into the geological sciences.
In the interim, until this important matter is given full consideration by the Quaternary community, INQUA recommends that the "Quaternary" be retained as a
System separate from the Neogene, comprising the Pleistocene and Holocene (the status quo). If temporary retention of the status quo is not acceptable to IUGS,
INQUA recommends that ICS formally adopt Brad Pillans' proposal that the Quaternary be a formal Subsystem of the Neogene, extending from the beginning of
the Gelasian Stage of the Pliocene to the present. Through its consultation with the Quaternary community, the INQUA Executive Committee has found
near-universal support for extending the Quaternary from its present lower boundary at 1.8 Ma to 2.6 Ma, the beginning of the Gelasian Stage. There is also
widespread support for maintaining the "Pleistocene"and "Holocene" as formal Series.
The International Association of Geomorphologists shares INQUA's concerns and has issued the following official statement, which is consistent with INQUA's
position:
The International Association of Geomorphologists (IAG) has considered the proposed revisions to the Geological Time Scale by the International Commission on
Stratigraphy. The IAG regrets the proposed elimination of the Quaternary as a system. However, if this change does take place then it supports the idea
that within the Neogene a Quaternary Subsystem is established with a long time-scale (i.e. the last 2.6 million years). This would remove problems with regard to
the placing of the Plio-Pleistocene boundary, and would reflect the major changes in the global environment which took place at 2.6 Ma (as recorded both in loess
sections and in the deep sea oxygen isotope record.)."
John J. Clague
Gordon M. Shrum Professor
Canada Research Chair in Natural Hazard Research
Department of Earth Sciences
Simon Fraser University
Burnaby, British Columbia
V5A 1S6
Bus: (604) 291-4924
Fax: (604) 291-4198
E-mail: jclague@sfu.ca
Web: http://www.sfu.ca/ ~jclague
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