Paleonet: International Geological Timescale [SEC=UNCLASSIFIED]

Charles Murray Henderson charles.henderson at
Thu Oct 4 05:09:10 UTC 2012

You are right I did miss the point. As a former ICS subcommission chair and an author in the Time Scale book I think it is very unfortunate that these two time scales differ. It is not a good message to our community. They are identical for the Permian, except for the PTB, which is 252.17. That will be corrected on the next ICS version, which I strongly lobbied at Brisbane meeting. I think you and others should ask Stan Finney (ICS Chair) to revisit any other levels where you have concern. It can be changed online quickly and new printouts will be prepared in the future I understand. It shouldn't be too much to ask for them to be identical, but in this case, personalities clashed and it didn't happen.


Charles M. Henderson Ph.D. P.Geol.
Professor and Head
Department of Geoscience, University of Calgary

From: paleonet-bounces at [mailto:paleonet-bounces at] On Behalf Of John.Laurie at
Sent: Wednesday, October 03, 2012 6:36 PM
To: PaleoNet at
Subject: Paleonet: International Geological Timescale [SEC=UNCLASSIFIED]


Most of you seem to have missed the point of my diatribe. I am not unaware of the process of working out the finer points of a geological timescale, with all the uncertainties that entails. Back in the 1990s, I was involved in developing a standard version for use in this organisation (see Young & Laurie, 1996) to replace GTS 1989. All I wish for, is that in 2012, when the two timescales which arrive on my desk, actually agree, as they did in 2004. Of course I realise that these beasts are provisional; that is the nature of science. If they weren't, all geochronologists could pack up and go home.

The explanation provided by Jim Ogg (via Erik Anthonissen) clarifies things to some extent by explaining the reasons for the disparity. However, this still does not alter the fact that the two sources of the timescale disagree. The ICS version has the imprimatur of the ICS, while the other has the utility of Timescale Creator. Is it too much to hope that they should actually talk to each other?


Dr John R. Laurie
Energy Division
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Canberra ACT 2601

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