Tuesday, June 27, 2017

Mountain building according to Plate Tectonics

(One for the Hill-buildies - the footsoldiers of Plate Tectonics)

"Even if midplate earthquakes are far less frequent than those on plate boundaries, if they have continued for any length of time they should have shoved up some hills."   (Shawna Vogel, p.165, "Naked Earth - The New Geophysics, 1996.

"Uhh?  ... Should have shoved up some hills.." ???

Well, ..why not?  Stands to reason, ...doesn't it?  Mountains can't just suddenly 'appear', .. ready-built, as it were, can they? They have to get pushed up by colliding plates, ...moving across the surface of the planet at the rate of centimetres a year.

That at least is the litany handed down by the experts, the popes and the cardinals,  of the Church of Plate Tectonics:  "Plates collide, crumple the crust and push up mountains."   So it's logical that before there are mountains there must be hills first.  (You have to laugh, ..little hills, .. sprouting like cabbages all over the place, ...getting pushed up and growing into mountains. If erosion doesn't get them first that is, and rub them all back down flat again.  In which case they would never get to be mountains. )

But (according to Plate Tectonics) they *do* get to be mountains.  Big ones, ..  Like the Himalayas.   The problem for Plate Tectonics however is that nowhere on the planet can anyone point to hills that are growing into mountains.

Oh, sure, ...they can do it for *mountains* already built, which are growing into higher mountains, like the said Himalayas, which we're told are getting higher  by the year..  but not for hills.  How come?  You'd think if we can do it for mountains that are already mountains, then we could do it for hills that have yet to become mountains..   In fact you'd have to think with all the growth illustrated for the Himalayas that 'researchers' would be falling over themselves to show it happening everywhere else too.  Two thirds of the planet (which is all the oceans), is a zone of plate separation, so conversely the remaining one third (which is all the land) must be substantially affected by plate convergence.

You'd think on that kind of scale the remaining one third would feel the effects of all that collision.  But no, .. collisional effects are said to be restricted to the knife-edged plate margin of so-called subduction zones, which take up only one half of the perimeter of the land available to be squeezed anyway. [No squeezing along the periphery of the Atlantic, Indian and Southern Oceans.]  So, ..what? Do hills only grow there?  What about all the hills in the interior of the continents?  There's lots of them, are there not?  Are these growing into mountains?  ... or being ground down from mountains, ..and how would you tell the difference?  And what then anyway?  Did all these hills (being ground down from mountains) used to be mountains that formed on old subduction zones?

 (Hey, .. More research opportunities..)

You'd have to think too, in the face of the obvious extreme erosion that exists in the Himalyas, with frost and glaciers and avalanches stripping them back like there's no tomorrow, that the assertion of mountains 'getting higher' smacks a bit of the rubbery abracadabra used by geophysicists to explain subduction and plate movement in general, and India in particular (not to mention the gee-whizzery of Scientific American).  Because how can they possibly know if the Himalayas are rising or not against the obvious destruction [1] [2]?  After all, the peaks are covered in snow that goes up and down like a yo-yo by the month, if not by the day, and they're all of different heights and miles apart anyway, with big gaps in between.  How do you average all of that?  By rubbery arithmetic about dyke intrusion at the Indian Ocean spreading ridge pushing an entire ocean floor?  I don't think so.  Who do geophysicists think they're kidding?  You?

What about the climate scientists while we're at it?

So what is it of this rambunctious 'hill-building' they're actually measuring here (as distinct from hallucinating about), this 'fact' of continuing uplift of mountains?  Sounds like more hat-magic to me, a rabbit from the hat of geophysical distractions and assumptions, aided and abetted by spruikers of the media ever greedy to wow the gullible public in order to sell more advertising - and indirectly, you... ...

So what is it,  makin' them thar hills... ??   (I mean mountains...)  And where are all these growing hills

Whatever the answer, it's clear that overall the rate of uplift (...and 'hill-building' - since we've *got* hills) is greater than erosion, otherwise there wouldn't be any (hills).  Everything would have been eroded down to 'zilch' long ago (repeat link)

The irony is, that rapid though erosion is (reducing the rocky surface of the planet to near flat in the blink of a geological eye so to speak), uplift, from time to time is indeed faster, ..i.e., 'uplift', not in the sense of colliding-plate crumplecrust Plate Tectonics, but as is expressed simply in the height differential between land and sea level, as an outwards movement of the Earth's surface from the core, which allows the sea-level to fall and consequently the land to 'rise'.

That 'from time-to-time' is apparent in the erosional adjustments of the land surface as deviations from equilibrium are stripped back to zero in the blink of a geological eye.  Instantaneous for water, slower for erosional detritus, even slower for non-diastrophic solifluction and slower still for layers of rocks gravitationally adjusting to the new curvature of the planet, it is *this* process, and the serial adjustments from the flatness of an earlier Earth curvature to the flatness of a later one, in a milieu of planetary spin, that underpins the surface tectonics of the planet.

It seems to escape the attention of geologists and geophysicists alike, that in order to balance the extreme extensions that have created ocean floors (= two thirds of the surface of the Earth) hills must be sprouting everywhere across the remaining one third of the land, not just on the knife-edge of subducting fronts squeezed up (supposedly) in response to compression by colliding plates.  But overwhelmingly the 'active' behaviour of the planet is the formation of a big flat land only punctuated by outliers of passive hills that are being reduced by erosion, not crops of sprouting hills growing into mountains by the fertiliser of colliding plates.

Saying it again?  *Overwhelmingly* the active dynamics of the Earth's crust is erosion and towards flatness, not towards building mountains just on the periphery of so-called plates, particularly when those mountains are largely dissected plateaus, and not 'crumplecrust' (such as is most apparent in the deeper levels of the crust).  And the tendency to 'flatness' (erosion) *can* only occur wherever there is a curvature differential of the planet leading to gravitational instability.

 Australia - that big flat brown land with its ancient erosion profiles - and dinosaurs right on the surface, .. just lying there. ...  Amazing.  Absolutely amazing. (Almost still running about.. )

And as the successions of erosional profiles across its surface as far back as the Mesozoic show, it always has been (tending to flatness; i.e., the new curvature at that point in geological time).   Any lumpy-bumpy deviations from this flatness that may be observed, including the Himalayas, are hills that are getting naturally eroded *down*, not hills that are obediently building up to the beat of a geophysical drum.  And by degrading to flat from a once-flat surface which was largely the sediment of a sea floor ('flat-to-flat'), geology tells us this change from 'flat' to 'flat' is by far best interpreted as curvature correction as the (spinning) planet gets bigger and slows. That is the true geological cycle, .. periodic pulsatory outwards movement of the surface of the planet, or its corollary, the periodic collapse of the pre-existing cratonic curvature, inscripted in the periodic stripping down of the crust and exposing ever deeper profiles of the crust as the planet gets bigger.

Mountain building (like hill-building), ..orogenesis, .. is a furphy.  There is, and quite possibly only ever has been,  one 'mountain belt', ..the precursor to Pangaean equatorial rupture and Pacific extrusion.

[ Volcanoes - the only mountains that get built. ]

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