Friday, 12 June 2015

Grand Canyon Catastrophe For Creationism

Geomorphic constraints on the age of the western Grand Canyon

It can't be easy being a creationist.

The problem is the need to be increasingly inventive to cope with the troublesome cognitive dissonance that comes from trying to stick to a belief while the evidence against it just keeps on piling up. This makes them prey to pseudoscience charlatans who will try to sell them spurious confirmation of their bias with lies, misinformation and misrepresentations of the data.

It also means they have to avoid reading proper science like a claustrophobe avoids lifts.

For example:

The Grand Canyon was not laid down slowly then etched out over the course of myth-ions and myth-ions of years. Rather it was carved so rapidly that the sediment was not deposited in a delta downstream. Buy a map and take a look. No river delta. The Grand Canyon was mostly carved quickly shortly after the Great Flood in a similar fashion to the "mini-grand-canyon" on the north side of Mount St. Helens. The little Colorado River does fall into the Grand Canyon from the side (just look at the map again) and then flow down the middle, but scientifically-speaking that little river did not carve the big Grand Canyon.


Note the way this cites the lack of a delta as evidence for rapid formation. In fact, the lack of a delta is evidence for slow formation and coastal erosion. A rapid formation would build up a continental shelf deposit more quickly than it could be eroded away by long-shore drift. In any case, delta formation depends far more on coastal geography than on speed of formation. But hey! Why bother with truth and accuracy when the idea is to sell books to people who want to remain deluded?

The real science, of course, is different, and doesn't need to defend a sacred dogma because people who do science and are led by evidence, actually want to change their minds.

For example, this paper on the age of the Grand Canyon undermines yet another cherished creationist belief that somehow the Grand Canyon is evidence of a young Earth and a recent flood, believing it was made when all the water ran off Earth after the flood (sic) and cut a groove in the sediment that had settled out. This of course would mean we should expect to find fossils of all the modern species of animals that had been killed in a few days in the supposed flood, and from all over the globe, all jumbled up and appearing throughout this 'sediment'.

Also, the creationist 'theory' that the Grand Canyon formed virtually over night predicts that each part of it should have the same age. Once again, the facts falsify the theory but then having a 'theory' falsified by the facts is not normally regarded as a problem in creation 'science' where the sacred thing is that the theory conforms to what the Bible says. Facts can always be ignored or waved aside as 'wrong' by defining anything that doesn't agree with your 'theory' as wrong.

Having said that, dating the real age of the Grand Canyon is not a simple task for geologists. For one thing, it has formed gradually, and gradually extended, so you would expect different sections of it to have been cut at different times. Depending on where they look, geologists have come up with two widely different estimates which not only seem to conflict with what was previously thought but which come up with two new widely differing estimates which clearly can't both be right.

The generally agreed explanation for how such a deep canyon was formed by a relatively modest river is that the land is rising slowly; slowly enough for the river to cut into it but not quickly enough to cause the river to divert around it. Once a deep gorge had been formed the latter option was impossible anyway because the weight of any water building up behind a dam would have burst through the dam almost before it could form. The only unresolved question was when exactly this erosion started.

It was generally agreed that this started about 6 million years ago, but then new data became available that suggested the Grand Canyon had started to form about 17 million years ago and on a second estimate, had remained substantially unchanged for about 70 million years. As so often with science, better data frequently causes current best estimates to be revised and may even reveal uncertainty where there was previously agreement.

Now Andrew Darling and Kellin Whipple of Arizona State University, School of Earth and Space Exploration, believe they have resolved these differences and can show that the previous 6 million year estimate is probably the best:

Abstract

Hypotheses for the age of the western Grand Canyon (WGC) range from younger than 6 Ma to older than 70 Ma. We study the relationships among topography, geology, and available erosion rates in space and time to place constraints on plausible canyon incision histories. Evidence suggests that lateral retreat of the Shivwits Plateau escarpment left a lithologically controlled bench on the Sanup Plateau, but the Hualapai Plateau is beveled indiscriminately across rock types of the Paleozoic stratigraphic section. A period of accelerated base-level fall in the Tertiary is implicated by the canyon incised into the beveled Hualapai Plateau surface, consistent with higher erosion rates observed in canyons than on the surrounding plateau. Streams draining the Hualapai Plateau preserve relict headwater segments that were equilibrated with a slower base-level-fall rate before canyon incision. These relict segments are now separated from the Grand Canyon by knickpoints indicative of a transient landscape. Relief production since the beveling of the Hualapai Plateau is ∼1000 m in the WGC. Comparison of hillslope and channel morphologies between the Grand Wash Cliffs and the WGC provides a test to distinguish hypothesized ages of canyon incision. The data strongly suggest that carving of the WGC is younger than relief production due to slip on the Grand Wash fault ca. 18–12 Ma. Thus the geomorphic data are only fully consistent with the late Tertiary, transient incision model of canyon incision beginning at integration after 6 Ma.


This is at the lower end of the different estimates and doubtless geologists will continue to debate the issue until any remaining conflict is resolved but even this 6 million year estimate for the 'birth' of the Grand Canyon must be distressing for creationists who now have to try to compress it down to about 4000 years, as well as explaining all the missing fossils. It will be interesting to see how the creationist frauds at AiG, Creation Ministries and ICR misrepresent this development for their credulous followers.

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2 comments :

  1. So there is a raging great torrent with sufficient power to carve out the Grand Canyon overnight. It covers the whole earth so that no place escapes. And while it is carving out geological phenomena like the GC, elsewhere there is a wooden structure about 450ftx75ftx45ft which is constructed using timbers none of which are longer than the height of a gopher tree. It is made using exclusively bronze age technology and it is bobbing about happily and safely on the surface of this raging torrent.

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    1. I would imagine when you're hermetically sealed in a small vessel with tens of millions of animals for about a year, being destroyed in a raging torrent is the least of your worries. Even the tiny window wouldn't have been enough for gas exchange, and anyway, all the plants had been killed too ,so nothing would be making any oxygen. :-)

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