WASHINGTON – The Andes Mountains may have growth spurts, doubling their height in as little as 2 million to 4 million years, US researchers reported on Thursday.
Their findings suggest that current theories about plate tectonics — the process that creates and moves continents, giving rise to mountain ranges — may need updating…
Garzione proposes an alternative theory — that delamination causes the root to heat up and ooze downward like a drop of thick syrup, abruptly breaking free and sinking into the hot mantle. The mountains above, suddenly free of the root, then spring up…
Read more here: http://www.planetark.com/dailynewsstory.cfm/newsid/48697/story.htm
Story from Planetark via Reuters. Reporting by Maggie Fox; Editing by Will Dunham and Xavier Briand
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
There is problematical logic operating here.
1. How does the mountain root heat up when the only heat source is decaying radiogenic heat.
2. Floating on the mantle implies the root is less dense than the underlying mantle.
3. Heating it up decreases the density even more.
4. Less dense materials cannot sink into a more dense medium.
5. So the observation that the mountain sprung up suddently cannot be explained by the proposed mechanism.
Isn’t it wonderful what geological inference is capable of – and it is intellectually the same time of abstraction as climate modelling – hypotheses disconnected from physical reality in which anything is possible.
Correction – same “type” of abstraction……
And Mountain “Growth”? Grows means getting larger – here it means getting taller, or higher.
This paper seems to be pseudoscience.
Oh poor science!
Seems curious to me.
I especially like the delamination scenario – a bit breaks off, sinks down into the mantle, and the remaining but bobs up. Pure fantasy.
How something less sense can sink into something more dense obviously isn’t a problem.
Louis,
with these mountains losing their ballast maybe we should calculate the righting moment of each one to be sure they do not blow over in those Andean winds.
Planet Ark could do with their righting moment correcting too.
Always been a bit light on ballast.
Louis,
As a geological amateur, it seems to me that the ‘root’ could be more dense than the magma, and so sink if it broke off. Think of a cork block with a big nail stuck in the under side. It could float, but if the nail fell out, the nail would sink, and the cork would float higher.
Yep there is a density problem…. So giving this hypothesis credence for a moment longer. How would we reexplain it…
What happens when you push a sheet of glass under a bed of molten tin?
In the Pilkington method of glass manufacturing they float molten glass atop of a moving bed of molten tin because of their different melting temps and densities… So what happens when a sheet of solid glass projects down and is subject to a scaled approximate of a continental plate?
Buggered if I know…
But if a significant portion of the plate melts off, or parts company with the rest of itself…. It would be lighter. But does that actually mean anything…. Would the denser material then push the glass plate or try to push the glass plate back out?
… anyway that’s about all I’m good for on this.
Green Davey and J. Hansford,
I’ll explain it in a little more detail once I catch up on some research – it’s important to understand how the idea of mountain cores came into the geological lexicon in the first place.
All my text books are locked in a storage facility in Perth 3000 km away, and I never thought I would need to refer to them concerning the issue of this thread.
But look up Isostasy and the surname Airey, a British astronomer who came up with the idea after surveying teams noticed that a plumb-bob’s deflection due to the mass of an adjacent mountain range was different to the theoretical value. (Crucial in surveying when theodolites are assumed vertically above a survey station on the basis of a plumb-bob being aligned along the radial extension to the centre of the earth, it’s centre of mass according to Newton’s Laws). These days the good old “jiggers” are replaced with highly accurate differential GPS machines and laser interferometry for distance measurement. I learnt surveying using Wild T3’s and T-1’s under Terry Tobin at the NSW Inst. of Technology during the late 1960’s while studying the Surveying Certificate.
(Oh, while it’s on my mind, Isaac Newton never reckoned he understood the cause of gravity, only that he could describe it’s motion).
I agree with Louis on the density issue – as it stands, it makes no sense.
Would need to read the full paper to understand the metasediment dating that allows the assertion “doubling in height in 2-4 million years”
The NZ South Island Alps are certainly currently increasing in height, but nowhere near this rate. The tremors from the plate movements causing this are well recorded of course.
Thanks for your comments, Louis. I will check up on isostasy and Airey, and look forward to your future comments on the matter. As the case for AGW seems to be collapsing, other perspectives from geology, tectonics, vulcanism etc. are well worth exploring. Career hungry academics might note this, and abandon ship before it becomes too obvious why they have done so. Imre Lakatos offered a few useful ideas on ‘degenerate research programs’.
I just discovered the latest Microsoft file indexing service had not indexed my 500Gb storage drive where all my research data is stored ( thousands of papers and articles) so I have to wait until the indexing completes before I can add further comment on this topic.(Miocrosoft seems to be in two minds with indexing services – you think something is being cataloged but discover it isn’t. Very frustrating – over 15 years of data collection and it cannot be searched at present).
Having said that, I should also point out that plate tectonics isn’t a valid geological process either and plenty of papers on http://www.ncgt.org
So if subduction is not occurring, then the whole scenario described in the article is also wrong but I do accept the conclusion that the Andes rose up in a spurt – it’s the mechanism of how that was achieved that is the issue.
Another very useful line of analysis is to look at the seismic tomographic data but one should be cautious – Some years back I recalled one analysis that concluded that the mantle was a tri-lobed structure and found the paper using Google. Now it’s off the search engines, as far as I can tell.
All rather worrying really.
Anyone remember stress and strain?
Delamination releases mechanical energy due to friction within the moving pieces undergoing shear after a long buildup of strain. Think of it as tectonic rug burn.
Repeated delamination would heat the root up until it reached the heat of melting and then it could all go at once because its under much greater pressure than the surrounding rock.
Once it melted, it would no longer be anchored to the rocks above which would rise and the melted root would fall. The plate would move into the void.
Austin,
So the mechanism is plate tectonics? But that has been comprehensively falsified for various reasons which I won’t go into detail here but some of the papers can be read on http://WWW.NCGT.org
If PT is invalid, how then to explain this accelerated rise? (and the electrical supply to Halls Creek is off, as well as all the land telephone lines because some idiot dug up the Telstra Cable, again)