How Old is the Grand Canyon?

Who Knows the Age of Grand Canyon?   11/30/2007    
“In spite of over a century of work on the Grand Canyon, there are still fundamental questions about the age of the canyon and the processes that have formed it.”  Thus begins a paper in the November GSA Bulletin of the Geological Society of America.1  To re-evaluate the date of Grand Canyon, a team dated lavas comparing argon-40 and argon-39, examined fault lines, and modeled rates of downcutting by the river.  Their result?  The canyon is half as old as previously thought: from 1.2 million years maximum, to probably less than 723,000 years – maybe even as little as 102,000 years.
    This represents another step in a long trend of falling ages for the world’s most famous canyon.  John Wesley Powell thought the canyon was 70 million years old – a date that stuck for nearly a century (source: RAE.org).  In more recent decades, 5 million years was the consensus figure.  Now it’s getting down into the hundreds of thousands (07/22/2002), with no end in sight.  Textbooks can’t keep up with the scientists, though.  This website for Utah fifth graders, for instance, nonchalantly tells the kids the canyon is 10 million years old.
    Meanwhile, creationists have long argued that the canyon is very young.  Their most popular model has a large lake upstream breaching its dam and carving the entire canyon within days or weeks.  Remarkably, some secular geologists are warming up to that idea, supplying their own variations on the dam-breach theme but putting the event farther back in time (09/30/2000, 05/31/2002, 07/22/2002, 09/16/2005).  Who knows; maybe tradition makes it hard to give up those millions of years.


1.  Karlstrom et al,40Ar/39Ar and field studies of Quaternary basalts in Grand Canyon and model for carving Grand Canyon: Quantifying the interaction of river incision and normal faulting across the western edge of the Colorado Plateau,” GSA Bulletin, Volume 119, Issue 11 (November 2007), pp. 1283-1312.

Our commentary is based on analysis of this paper by a field geologist with over 28 years’ experience in the oil, gas and mining industries, who has also given presentations about the Colorado Plateau.
    The authors of this paper cherry-picked their data.  They only used 26 of 63 radiometric dating tests – that is tossing out 60% of the data.  How can we trust their results?  Even then, the spread in resulting ages is huge, but they never questioned the validity of their dating method.
    In addition, there is a large discrepancy between the dates of lavas on the Uinkaret Plateau (3.4 to 3.7 million years) and those of intracanyon flows (100,000 to 700,000 years), but they assumed that their results are immune from the flaws of earlier attempts.  Regardless, they had to admit that radioactive dating of basalt is very difficult, particularly in Grand Canyon.  They also acknowledged large discrepancies between radioactive dates and those determined by stratigraphic position: in one case, they were off by more than two standard deviations.  The way out was to use a method of “recalculating errors to better reflect scatter of the dates beyond analytical error.”  Some stratigraphic dates agreed with the radiometric dates, but the above discrepancy stuck out like a sore thumb.  What did they do?  Ignore it!
    The incision rates (downcutting of the river) they modeled would require 10 to 12 million years to carve the canyon – much older than the date they got from radiometric methods.  They tried to correlate incision rate with faulting rate, but those are two processes that have nothing to do with each other; to get disparate pieces of the puzzle together, they allowed incision rates to vary by nearly 1000%.  When needed, they added some ad hoc forces to keep things in sync: raising the whole Colorado Plateau by a “buoyant low-velocity mantle upwelling.”
    In short, our geologist concluded, “RA [radioactive] dating can give any date you would like, depending on where you sample and what method you use.  Because the evolutionists’ assumptions are wrong they are asking the wrong questions, using the wrong methods, and generating wrong interpretations.  What a waste of time and effort.”  (See 09/19/2007).
    Scouring through the jargon and numbers in this technical paper, it is apparent that these geologists were trying to piece together a lot of uncooperative data into some kind of patchwork that gave them a human sense of accomplishment.  Undoubtedly the team felt gratified for getting a paper published by their peers in the Geological Society of America.  Whether their claims have any necessary correlation with what actually happened at Grand Canyon is an entirely different question.  Here, it is publish and perish – perish the thought that their assumptions might be totally off kilter.  See 11/05/2003, 11/04/2003.


Opportunity:  Want to see evidence for a young canyon with your own eyes?  Join us for the Memorial Day 2008 3-day rafting trip in Grand Canyon! (see sample picture).  Click here for details on this fun-filled, educational vacation package.  Don’t hesitate – the trip is expected to fill by January 2008 or before.
Next headline on:  GeologyDating Methods

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