Geological Column, Rev. 2004-a

The geological column is not “set in stone,” John Whitfield discovered as he investigated the work of the International Commission on Stratigraphy (ICS), which is releasing a revised column this summer.  “Silurian, Devonian, Triassic: the names seem as solid and permanent as rocks themselves.  But in fact,” he cautions in his report in Nature,¹ “like fashions in hair or hem-length, the geological divisions of our planet’s timeline are prone to change.”
    Rocks, naturally, do not come with dates or names on them.  The column is largely an artificial construct intended to bring some kind of universal order to the many varied assemblages of rocks and strata, and their fossil contents, around the world.  Just as hair and hem lengths can vary by large margins, the dates and boundaries of the eras, epochs and periods within the column are largely a matter of convention.  Sometimes those conventions fall prey to local disagreements:

Over the past 150 years, geologists have struggled to unravel Earth’s history.  To a large extent, they have relied on significant events, such as the appearance of a specific fossil, or a reversal in the planet’s magnetic field, to define the boundary between two time periods.  Having defined these physical boundaries, researchers then attempted to date them.  But geologists in different parts of the world used different rocks as benchmarks, leading to disagreements over the exact definition of each period.

    Lately, however, geologists have been trying to nail down some calibration points with “golden spikes.”  Whitfield explains,

To resolve the issue, stratigraphers are deploying ‘golden spikes’ – also known as global standard stratotype-section and points (GSSPs).  These are locations where a good example of a worldwide event can be found, nominated by working groups within the ICS and then ratified by the IUGS [International Union of Geological Sciences].  Once a spike is set, that rock remains the boundary of a time period, even if estimates of its age change.

There are now 50 golden spike points around the world, and the number is growing.  But what about their dates?  A method growing in popularity is to calibrate them with astronomical events, such as changes in earth’s orbit that led to climate changes on earth.  Geologists gather clues about these changes by measuring oxygen isotope ratios and calcium carbonate concentrations in rock.  Whitfield claims this method is accurate to 65 million years ago and is improving.
    Geologists try to refine the dates with radiometric dating.  “But in the past decade,” Whitfield laments, “it has become clear that the results from different techniques and different labs don’t agree.”  The solution?  A global network of laboratories, all using a standard procedure, should be active in about a year.  Maybe then geologists can extend their column to the entire solar system.

¹John Whitfield, “Geology: Time Lords,” Nature 429, 124 – 125 (13 May 2004); doi:10.1038/429124a.

Though he trusts in it, Whitfield treats this whole process something like a game, because it is.  Do you see the flaw?  The geological column has more to do with consensus than fact (see 12/27/2003 editorial).  The geologists are confused because their evolutionary just-so stories don’t agree.  So they are like a group of independent Hollywood producers who want to form a consortium where they can all come to agreement on their screenplay for Planet of the Apes.  And like any game, you have cheering fans.  Whitfield describes how China responded when they won a golden spike: “To Chinese stratigraphers, this was the equivalent of winning a bid to host the Olympics.  They hoisted a six-metre-tall monument on the spot to commemorate the achievement.”  This means no more than getting recognition from the director of a science fiction movie.  It may make them feel good, but does it tell them anything about the real world?
    It takes a skeptic to read this kind of literature without being hoodwinked.  There’s plenty of reason to doubt that geologists are really unraveling Earth’s history, and plenty to arouse suspicion they are engaging in self-deception by consensus.  Some examples from this article, in addition to those stated above, remind us of Dewlap’s Laws of Physics, namely: (1) Fact is solidified opinion; (2) Facts may weaken under extreme heat and pressure; and (3) Truth is elastic.  See for yourself:

• Flexible boundaries:  “The end of the Jurassic period, for instance, has wobbled by more than 30 million years since it was dated in the 1930s.”
• Babel:  “The new scale will help Earth scientists speak to one another in a common language, and the dates will help to answer questions about what caused various mass extinctions and changes in climate.”
• Fuzz:  “But despite being the most complete work on dates so far … the new timescale is not definitive.”
• Flux:  “Its assembly has rekindled a long-standing debate on how to define the earliest geological time periods, and many of those boundaries look set to change in the next few years.”
• Stretch:  “And as the dates are re-examined, the timescale may even widen to encompass rocks beyond Earth.”
• Politics:  “In 1999, the IUGS executive called for a concerted effort to find GSSPs, and the past few years have seen a surge of activity.  Political as well as scientific arguments ensued.”
• Laziness: “In the debate over where to put the spike separating the Permian from the Triassic, the relative inaccessibility of sites in Kashmir and Iran helped to rule them out in favour of one in Zhejiang Province, China.”
• Everything You Know Is Wrong:  “‘Most people will tell you that a measurement more than five years old is obsolete,’ says Gradstein.”
• You’re Not Getting Older – You’re Not Getting Better:  Uncertainty over dates is a particular problem for the early life of Earth.  When these time periods were established [by consensus], it was thought that there would be too few benchmarks to define GSSPs: rocks get rarer as they get older, and there are no large fossils from that long ago.  Instead, each period is anchored by round dates rather than golden spikes.  Most of the Precambrian, the first four billion years of Earth’s history, is chopped up in this way.”
• Armchair Strategy:  “Some Earth scientists have railed against this system ever since the ICS decided on it in the 1980s, complaining that it is inconsistent.  ‘There’s been a ferocious debate between a bunch of field-based mavericks and the committees,’ says geologist Euan Nisbet of Royal Holloway, a college of the University of London in Egham.”
• Missionary Fervor:  “More ancient spikes are set to come.  The new chairman of the ICS Precambrian subcommission, Wouter Bleeker of the Geological Survey of Canada, Ottawa, is on a mission to use rock features to divide up the deep past.”
• Sans Rigor:  “To define such ancient spikes, geologists will need to relax their criteria.  There is no worldwide record of the Ediacaran changes seen in Australia, and this will be true for other spikes in the distant past.”

Field geologists do a worthy work, and there is nothing wrong with trying to classify and bring order to a bunch of heterogeneous data.  But the geological column, with its stories about dates and evolutionary epochs, is a script, a framework, a game, an evolving consensus, a prescriptive set of orders, a set of colored glasses, not a fact.  Go out and look at rocks at various locations.  It’s not obvious that this rock is a billion years older than that rock.  It has nothing to do with the color, texture, grain, mineralogy, or hardness of the rock, but rather where it fits in the screenplay.  Evolutionary geologists will claim that even with the uncertainties they are in the ballpark.  But the park is owned by the Darwin Party, and the D.P. sets the rules of the game.  They can’t lose.
    There you have it: a bunch of Hollywood scriptwriters building a Tower of Babel for the Planet of the Apes.  If it’s self-consistent (with a little forcing), and if everyone agrees (with a little forcing) how could it be wrong?  (Now read what they did to homology – see 05/05/2004 headline).