Friday, July 28, 2017

Mountain building is not obvious

"What keeps building mountains is not obvious."  Certainly isn't (Hi Andrew).  But what keeps making valleys (and the Earth flatter than it used to be), certainly is. 

(Please note red/yellow highlighted links are notes to self to deal with later (1st edition revision), as I work out a best way to inveigle you to my way of thinking.  :-)  (Some 'regular' links will work but the red/yellow ones won't.  It's just to make them easier for me to see later.  (Work in progress, in slo-mo.)

"Building"?  .... What is it about mountains that gets 'built'? If mountains are really eroded plateaus, (link.) why does the term 'mountain building' pervade the literature so, to describe these landforms?  (=>)

Fig.  1.  Drakensberg Mountains, South Africa.   A classic example of the way in which rock layers of one sort and another are piled one on top of the other to build mountains.

No? .. That's not how mountains are built?   It might as well be, given the many other nonsenses (link) that Plate Tectonics expouses.  And when you think of how that lot *are* built up from material derived from an extraneous source, how is it different from the mountains 'built up'  from the aprons of a volcano to its summit?
" .. Geologically speaking, the entire highlands of the Simien Mountains consist of dark trap basalt and bright, soft turf. They alternate and constitute a massive complex that is more than 3000 m thick. This complex was formed by volcanic eruptions in the Tertiary Oligocene-Miocene Age some 20-30 million years ago; ever since, it has been going through processes of uplifting and erosion." (Link)

Well, I don't know so much about "uplift" given what has been mentioned already about uplift.  That's a point of contention. So how then?  Where precisely do we go in the world to discover the intense deformation (/ "crumpling) of crust - the 'orogenesis'', the 'mountain building' - that builds mountains?  Mount Everest (link)? or its closer confederate, Mount Kailash (link)?  Or maybe the Italian Alps, .. or the Swiss Alps for that matter?

Plate Tectonics has a peculiar dichotomy when it comes to the notion of  'mountain building' ('orogenesis'), because it's not very clear what it means either by 'mountain',  ..or what it means by 'building'.  It's another of these terms of Plate Tectonics that's loaded with memic, almost mythical emotional appeal, but in actual fact (geologically speaking) means very little.

"Mountains".  ...It's just a big hill, but we don't, would never dream, of talking about hill-building.  Hills are fren'ly, where sheep safely graze, with maybe a fairy or two in a dew-spangled dell, but mountains are dark and forbidding, cloaked in snow and ice with gnomes and other subterranean denizens tunnelling deep within by day, and doing unmentionable things to Snowhite by night,  ...or spouting hellfire and fumes and molten rock.  The abodes of Gods.  Whatever, mountains have emotional connotations that hills don't, because they're pointy and steep, and most of all high, a barrier to the outside world, ..where hills allow you to peep over the fence, so to speak. 

This emotional baggage that mountains inspire, and the awe and wonder with which they are customarily accompanied, is no small consideration when it comes to probing the question (or shall we say 'secret' or even stories and myths) of mountain 'building'.  ("Of course they're built.  How can something that high, ...a wall to the world beyond,  *not* be built?  It's a lot higher than the wall around the footie ground, ...and *we* built that. So, ..?") ("Arsk yer local God if it's built, ..don't ask me.")

But apart from volcanoes this 'building'  has virtually no vestige in reality, despite the 27,000+ returns on google scholar.

Volcanoes are the most obvious expression of a mountain that's built,  but volcanoes are not examples of what is generally referenced by the term 'mountain building'.  Chains of volcanoes encircle the Pacific, but that is not what is generally meant by a 'mountain belt' either.  The Drakensberg mountains of Lesotho, South Africa for example (above) are mountains by name as are many others around the world, but they have clearly not suffered any 'building', ...any  'orogenesis', ..any 'tectogenesis', or any other fancy-name genesis invented to account for the upward construction of these awe-inspiring edifices.  They are manifestly an artifact of erosion, and erosion is the antithesis of building.  Likewise the spreading ridges of the oceans are acknowledged as the most extensive mountain belt on the Planet, but they clearly have not suffered any 'orogensis' (mountain building) either, in the sense meant by Plate Tectonics to describe the upheaval of the crust by crustal crumpling by plate collision that is usually meant to build mountains.  On the contrary, spreading ridges are formed by crustal extension.

So what then?  Does that mean there are different sorts of mountains, (link) matched by different sorts of orogenesis?  And if so, what sort of orogenesis / tectonic force was it that pervaded the planet globally to uplift the Mesozoic land surface of the world to form the Great Plateau of Africa (with its Drakens), ...and the other high plateaus from which (by erosion) were carved the Himalayas, the Alps, the American Cordilleras (north and south) and all the other highest mountains of the planet (except volcanoes) (...which are 'built') (...but that is not what is meant by mountain building.)

The answer is none - no sort of 'orogenesis' at all.  Plate Tectonicists don't have an answer for this continuum of elevation (link)  They don't even acknowledge the fact of The Great Regression (link)- the time in the Earth's history when the waters of the inland seas ran off the land to fill up the developing ocean basins.

Instead they invented (and keep reinventing) (link)Plate Tectonics -  a plethora of plates and a frenetic action that would do a fast-car drag meet proud, with its cavalcade of collisions on a roiling mantle boil.  There is no explanation in Plate Tectonics how these "independent plates" get their act together to push up (and 'build') either the linear continuity, or the uniform elevation which the present day mountain belts describe.  In fact Plate Tectonics with its independent colliding plates virtually ignores both continuity and uniformity.  Plate Tectonics has no answer to the question, "What causes the elevation of vast tracts of the planet to form plateaus?".  Plateaus are simply not accommodated in the grand plan of Plate Tectonics, ..not on its horizon.  There is not even a single index entry for it in the Bible of Plate Tectonics.   If they were (accommodated) then Plate Tectonics would not exist.  Just the existence of mountains contradicts the very essence of Plate Tectonic theory.  But somehow it is necessary to keep repeating the point, ,.. something that I've always known since I was a child in geography class (and probably you too), that mountains result from the carving of plateaus by erosion (and not by crustal crumpling).

"Mountains are not made directly by folding, but result from uplift of plains (planation surfaces) to form plateaus, which are subsequently eroded to form escarpments and isolated erosional mountains..." (Ollier, C.D., 1999, Society of America, Bulletin 70, 1047 - 78)

But the Earth sciences since then seem to have slipped a disc.  The reality is that there has been no perceptible deformation accompanying this elevation other than the scale-commensurate extensional rifting which has caused mantle extrusion and formed the ocean floors - and the scale-commensurate slumping within the continents and at their margins. (link) that went along with it.

But that is very far from the popular thematics expoused by advocates of Plate Tectonics.

"..What keeps building mountains is not obvious <...> but most mountains are pushed upward, their rock beds wrinkled like bedsheets or tilted like stacks of newspapers. The plates bump each other's edges in a slow-motion Demolition Derby, and that's where mountain ranges get their start. <.....> "Mountain belts are typically formed by plate tectonic activity, specifically continental collision." (From - Andrew Alden, 'Arm-wavers of the centuries - landforms and features',
So, .."What keeps building mountains is not obvious." ? For the very good reason that mountains are not built. They are erosional features.  All of them.  Except volcanoes which are built with slope, .. instead of flat - like the Drakensberg mountains above.
(Looks like Andrew has some rewriting to do..) 
Somebody should tell him.

So why does the term "mountain building" and its fancier moniker 'orogenesis' pervade the literature and popular belief so, even when the high tracts of the planet are so obviously plateaus, ..that are not crumpled.

The short answer is that the belief that mountains are formed by crumpling of the crust (by plate collision) serves consensus very well thank you very much ("The Gift that Keeps on Giving").  Of course geologists recognise the contradictions and conundrums, but there's nothing to be gained, no mileage in addressing the hard questions that lie down that road - only the oblivion of confronting Earth expansion.  Why kill the goose that lays the golden egg when there's more reward in parroting rote liturgy that needs no explanation?

The longer answer is what this site is all about.

Mountainous fold ahead.
One way.  Do not enter.
Wrong way.
Go Back.
< image >
(it's the one on the right.)

Question:- So what force is it, that builds 'wrinkled bedsheets' like this one?
 Answer: The same force that is reducing it to rubble :- gravity

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