mount st helens as a model for the grand canyon? somehow i don’t think so

Recently our local paper ran an article on Mt St Helens, which hit the headlines with a violent eruption back in 1980. The words ‘big bang’ were mentioned in the title. This seems to have struck a chord with one reader…

This mountain’s big bang, and the subsequent rapid remodelling of the area, ironically casts doubt on "the big bang", which we have been taught is what brought about our own origin over supposedly billions of years.

I quote the writer: "One of the largest landslides in recorded history ensued."

Yet this event was just a small reminder of how the Earth’s present surface was formed – by a rapid and catastrophic event. Mount St Helen’s eruption created a small version of the Grand Canyon in just a few hours. Therefore, significantly, what we see around us is not evidence for a slow and gradual evolution. An interesting book which discusses parallels to the Grand Canyon and Mount St Helens is available in the Hamilton Llibrary. It’s called "Footprints in the Ash", by John Morris and Steven Austin. You owe yourself a look at it.

(At the beginning of the third paragraph I was thinking, Young Earth Creationism, or YEC, and mention of John Morris & Steve Austin confirmed it.)

Although by no means the largest eruption in recent history, Mt St Helens was the largest for a considerable period of time in North America. It released around 24 megatons of thermal energy & its lateral blast produced a path of destruction that reached around 27km from the mountain. And it did result in ‘the largest landslide in recorded history’ when a debris-laden lahar travelling at up to 240kph rushed down the mountainside, filling the Touttle river valley with up to 180m of rock, gravel and ash. (There’s a good source of images here on the US Geological Service website.) After the eruption the ash and mud fields surrounding the remants of Mt St Helens’ cone were carved and eroded by rainfall to produce features like this:


Image source: Lance Wilson’s blog Mt St Helens Watch

This is ‘Step Canyon’. Steve Austin has called this ‘Little Grand Canyon’ although the formation hardly merits the name as it’s about 20m deep compared to the 1.5km of the real Grand Canyon 🙂 Leading into it is ‘Engineers Canyon’, which Wilson notes was formed rapidly by engineers pumping water out of a lahar-dammed lake further upstream. Austin, Morris & other creationists claim that because these two formations were produced so rapidly by erosive forces, this ‘proves’ that the Grand Canyon itself formed extremely fast & thus supports the idea of a young Earth (6,000 years or so old) with its geological features formed by the Noachian flood.

Unfortunately for this idea the authors aren’t comparing like with like. The debris fields around Mt St Helens are made up of rocks & gravels, ash & mud, & the remains of pyroclastic flows, sitting loosely atop each other – they’re not compacted or consolidated. All this is sitting on steep slopes, pretty much unprotected by any plant cover (particularly immediately after the eruption sequence), and in an area where the average annual rainfall is about 3m for year – a recipe for some pretty impressive erosion. The Grand Canyon is different.

This significant geological feature cuts through layers of limestone, sandstone, shale and metamorphic granite, a mile down to the Colorado River, arranged as shown in the following image from the TalkOrigins website

 Idealized and simplified diagram of the Grand Canyon – from TalkOrigins
Grand Canyon figure

These rocks are much more resistant to erosion than the unconsolidated debris fields of Mt St Helens, and their rates of erosion are much too slow to allow for the Canyon’s formation in the very short timespan of the YEC model. On the basis of radiometic dating those recent (Cenozoic) lava flows at the very top are around 1.3 million years old – because they flow over the lip of the Canyon they must have been laid down after it formed. Uranium-lead isotope measurements suggest that the Canyon is at least 6 million years old and was cut at rates of between 55 and 400 metres per million years

So we really are looking at a ‘slow and gradual’ event, and indeed, it was Lyell’s and Hutton’s documented evidence of slow, gradual changes in the Earth’s surface (subsequently validated by radiometric dating) that gave Darwin the time needed for the evolution of life to occur.

9 thoughts on “mount st helens as a model for the grand canyon? somehow i don’t think so”

  • The creationists like to call that St Helens canyon a 1/40th scale version of the Grand Canyon, although if those figures are right about relative depths then it’s more like 1/80th scale. Perhaps it’s 1/40th the length. But even if we accept that it’s 1/40th scale in all its linear dimensions then its 1/40 x 1/40 x 1/40 = 1/64,000th the size of the real Grand Canyon. So not really a comparable feature even if you ignore the differences in geology.
    Perhaps the biggest irony of creationist claims about the Grand Canyon is that we know what catastrophic erosion (of the type they argue formed the Grand Canyon) looks like. There’s an excellent example of it a couple of thousand miles to the north-west in the scablands of Washington, and it looks nothing like the Grand Canyon.

    • You might want to study it a little deeper AND also study the failures of 14C dating. Between the fact that 14C SHOULD be totally decayed in 5,730 years but yet there is 14C in the rocks used to date the Grand Canyon, AND these pictures of St Helens; they do look very Grand Canyon like in areas,

      And the fact that the Biblical Flood covered the earth for a year THEN started to recede. What damage and loosening of the earth was done during the one year soaking and then the receding waters?

      Compared to a few days of initial creation of St Helen’s canyons.

      • Some nice misdirection & straw mannery there. The rocks of the Grand Canyon were not dated using C14 techniques: potassium-40 would be the go-to, along with comparative data on fossils & strata. This link might be useful for your learning:

        The BIG difference between what you see on Mt St Helens and in the GC is that on Mt St Helens, ‘canyons’ were not being cut through miles of compacted rock, but through volcanic ash. So your comparison fails.

        And if you have evidence to support the assertion that the Biblical flood is a “fact”, do feel free to produce it here. From high-quality peer-reviewed geology journals, if you don’t mind.

        • Richard Anders says:

          Potassium dating us without flaw, just like carbon was years ago. There are assumptions in the dating. The real point to what is found versus the Grand Canyon is more real evidence, not quite proof, of a catastrophic flood.

  • You’re right the rocks were not tested for C14, but Potassium-40. But while correcting this misunderstanding, you missed the point. the rocks still tested as being thousands of years old when in fact they were just a few years old. This still shows the unreliability of radioactive dating.

    The layers at Mount St Helens solidified very quickly. It was 2 years after they were laid that the canyon was carved, and not from rain water but snow melt – due to another small eruption. If the canyon was carved in unstable material, then the canon would not have lasted 40 years. It would have continued to erode, and not remained steep sided.

  • Author of this article claims to be ‘criticak thinking’ and sneers at the idea that MtSt Helens Canyon cannot be compared ot Grand Canyon – because Grand was cut through ancient HARD ROCK!
    Idiot is too ignorant to know that Grand was cut through soft wet sediments at end of The Flood 4,350 years ago.
    Also doesn’t know that entry point of Grand is far higher than present surounding land which PROVES IT WAS CUT BY FLOOD WATER WHEN THE FLOOD WATER WAS DRAINING !

    Kaikato Uni is staffed by fools deliberately teaching lies.

    • Well. Rose, universities teach evidence-based material in their classes. They don’t teach young-Earth creationism because – as with assertions like yours – there is no scientific evidence to support it. And that which is asserted without evidence can be dismissed without evidence as well.

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