Wednesday, November 12, 2008

Neogene Chaos

The Tertiary is gone since 2003 but the discussion on the stratigraphic classification of the Neogene is still ongoing. For example, the International Stratigraphic Commission decided to ban the Quaternary from the official time scale, but geologists have sucessfully fought to keep this system (see for example this document). Both, Quaternary as well as Tertiary were regarded as 'remnants of the Neptunist concept of stratigraphy'. Strange, as recently, the 'Anthropocene' was proposed in 2007 by the Stratigraphic Commission of the Geological Society (UK) which also caused some blog echo for example here and here.

These 'outs' and' ins' are hard to follow, therefore the International Comission of Stratigraphy quite frequently provides updates on their stratigraphic chart at http://www.stratigraphy.org/cheu.pdf. Every time I visit this page this 'standard chart' looks different and unfortunately the stratigraphy.org page does not archive older versions of the chart for comparison.
Fortunately there is the Internet Archive which never forgets! Just visit http://web.archive.org/web/*/http://www.stratigraphy.org/cheu.pdf and you can download older versions of the stratigraphic chart back to 2004: a 'sequence of stratigraphic charts'.

Are you an old-fashioned geologists and still keep on using terms like 'Tertiary'? You are not alone ;) Indeed the Commission itself was not really sure how to deal with these Neptunistic concepts even after their 2003 decision. A closer look at these old charts quite nicely illustrates the discussion which followed:

  1. 2004 The Tertiary and the Quaternary ... both gone ...

  2. December 2005: The Quaternary is back! looks strange, but it's there..
    The * is a placeholder for the following footnotes:
    • until April, 2006: 'Proposed by ICS'
    • from October 2006 on: 'Formal chronostratigraphic unit sensu joint ICS-INQUA taskforce (2005) and ICS.'

  3. October 2006: The Tertiary is back!
    Footnote:' Informal chronostratigraphic unit sensu Aubry et al. (2005, Episodes 28/2).'



  4. September 2007: Tertiary off again.. and a strange line from Quarternary to the base of Gelasian..
    Footnote: The status of the Quarternary is not yet decided.




  5. Current version (Nov. 2008): Quaternary has two potential bases?



What comes next? The International Stratigraphic Comission provides an interesting pdf which is named: 'A Proposal for Simplifying the International Geological Time Scale Chart' ... and this is the simplification for the Cenozoic:

No comment...

3 comments:

Lost Geologist said...

For me has a student these back-and-forths were very annoying. Especially for starters in the first semesters it is usually confusing enough to learn the then current version. Frequent changes often intensivy the confusion. It would be nice if they could decide on one definition or another. I don't even care which one but just to end the roller-coaster ride.

Silver Fox said...

Aaarrgh! But great post and link to the past versions of the past.

effjot said...

And don't forget to extend your records by the 2009 version, which at least doesn't look as crazy as the last few tables you have shown in your post…

@Silver Fox: I like your “past versions of the past”. When reading the post, something similar came to my mind – stratigraphy of stratigraphy. Layers of stratigraphic tables, with a possibly incomplete record, as older parts are eroded away by some ICS denudation event.

I still don't understand why they don't keep the old versions. How are you supposed to understand discussions from some time ago when you can't even know the nomenclature? It boggles the mind.