Convenient Assumption of Subduction
(...where plate tectonics begins...So near, and yet so far...)
Fig.1. Subduction zones - As the statements of the Fathers of Plate Tectonics below show, the heavier trace of earthquakes around the Pacific and the Alpine - Himalyan region are assumed to be the zones of corollary destruction of the ocean floors partnering the spreading ridges (lighter red trace). They are not. Click here for the wysiwyg alternative view according to Earth expansion. (Image courtesy of USGS.)
|"If the creation of new oceanic lithosphere at oceanic ridges were the only process operating, the Earth clearly would have increased in volume and surface area at a remarkable rate in the comparatively recent geologic past" . "...large scale expansion is extremely unlikely...." "Thus, an important element of the seafloor spreading hypothesis from the outset has been the assumption that oceanic lithosphere is being returned to the mantle landward of the deep ocean trenches." F.J. Vine 1987. Encyclopedia of Structural Geology and Plate Tectonics (Seyfert), p.712 (confirming subduction was, and still is an assumption).|
|"..It is convenient, in the context of plate tectonics, to emphasise underthrusting (subduction) of one plate rather than overthrusting (overriding) of the other, although kinematically both are equivalent" John G. Dennis 1987. Encyclopedia of Structural Geology and Plate Tectonics (Seyfert), p.503 (emphasising convenience..)|
..The theory of plate tectonics is based on several assumptions, the most
important of which are:
( .. or google a word-string - for example)
There we go, ... Talk about assuming your conclusions before you even start looking ( = JUNK SCIENCE ... ! ).
This matter of assumptions, ..highlights the difference in approach between Geophysics and Geology. Geophysicists are clever, and reckon with some paper and pencil they can figger it out, and don't worry too much about the geology; ... Like Global Warning, get the 'rithmetic right and the facts are sure to follow. They have to make assumptions, usually at the top of the page ("Let this = that and that = this") so that the arithmetic will work. And then they think, after a bit of head scratching and a few tequilas, they're pretty smart when the conclusions = the assumptions. Geologists on the other hand are pretty dumb and wouldn't know how, mostly, .. and as well, knowing the relative sobriety imposed by outcrop, look askance at the scribbled eurekas shoved under their nose by jubilant geophysicists, creaming themselves over their own inventions.
The top of the page:- Growth of the ocean floors uncompensated by subduction means that the Earth is getting bigger. Plate tectonics says, "This is an impossible situation, because we can't figger out how this can possible be". Therefore, since there is no known mechanism by which the ocean floors can grow to the extent apparent, namely to create (not less than) two thirds of the entire surface area of the Earth, Plate Tectonics simply says:- "So, we can dismiss the possibility. Instead we will assume that subduction occurs. That way we do not have to consider the possibility of something we know nothing about, and what we think we do know, remains intact. Besides, we can see subduction in the seismic tomography. It is well documented."
..........................Fig.2. Circum-Pacific subduction zone. Showing the plethora of earthquakes encircling the hinge of Pangaean opening (Pacific / Indonesian / Himalayan and Mediterranean regions). Apart from the accompanying rubble of destruction, these epicentre plots on the map are literally the only physical evidence for subduction. (Image from USGS, July, 2010) (Any day of the week.)
And that, in a nutshell, is plate tectonics' position. But can we see subduction? Is it well documented? The answer is no, ...we can't. And it isn't. What we can see (that is well documented) is a zone of earthquakes that releases about ten times as much energy around the Pacific rim as spreading ridges and transform faults combined, and that reaches down to about 760 - 800km, and whose relative first motions of displacement are in fact much more ambiguous than the 'carrying down' of subduction says, and many of which are as much (if not more) sideways than down. But plate tectonics assumes that these earthquakes (= brittle behaviour) mean that the zone of mantle in which they occur (which they call a 'slab'/ 'mantle slabs') is cold, and is therefore more dense, and is therefore sinking. So when plate tectonics uses the term "subducting cold mantle slabs" as shorthand for what it intends to convey, it is being highly misrepresentative of the facts. It is in fact saying no more than "..a zone of Earthquakes that reaches down to 800km".
There are ways of interpreting that zone (as described on this site) other than plate tectonics says. The mantle is not necessarily 'subducting', nor even (as it supposedly 'descends') is it cold, .and the 'slab' is actually constituted of the entire ocean floor right back to the ridge, not simply the turned-down sector that Plate Tectonics usually labels 'slab'. If coldness and slabness is the point, why doesn't the entire ocean floor just sink? It is after all cold, and more dense than the mantle on which it is sitting. And it is huge - making up two thirds of the Earth's surface in fact. Why must it travel so far from the ridge before it is cold enough to sink? It's pretty cold right where it is, on an Icelandic slope, say, ..even in the sunshine. And why (if it is cold) must it always sink on a line (a continental margin)? Why doesn't it just sink anyhow, ...like a 'plate' - and zig-zag to the bottom? Because there is a space problem? ...no room for all that ocean floor at the surface to sit on the much smaller curvature of the core-mantle boundary? Or maybe, because gravitational force tapers off with depth it will tend not to sink at all after a while?
Nope, ..that's not it. According to Plate Tectonics it's not cold (/dense) enough. To become cold (/dense) enough it has to be pushed down into the hotter regions of the mantle where it can undergo a phase transition to its denser equivalent of eclogite. THEN it can sink ("because it's cold" - "because it's dense").
What? It has to sink into the hot mantle to become cold /dense enough to sink? Yup! That indeed is Plate Tectonic logic. And just in case we need another bit of logic in order to swallow that one we have to consider the other bit of PT-ers' logic, ...that to get down there in the first place the slab has to be forced down. How? Well, ...by the continental lithosphere at a 'plate boundary'. What's that? By the continental lithosphere that is lighter than the oceanic lithosphere, do I hear you ask? Well, .. yes again. That's more Plate Tectonic logic. It goes on and on, this logic, a bottomless Christmas Stocking jamboree of Wonderland possibilities to aid publication and career advancement. Can there be any wonder it's considered the greatest thing since sliced bread?
|"The development of plate-tectonic
theory certainly warrants a Nobel Prize," said Dr. Marcia McNutt, president-elect
of the American Geophysical Union. "There is no doubt that it ranks as
one of the top ten scientific accomplishments of the second half of the
What Ms. McNutt means here is for the way Plate Tectonic theory has unerringly served the career interest of decades of geologists - or more exactly, geophysicists. An alternative explanation and (given the setting) a far more likely one for these earthquakes (and the crustal brittleness of 'slab' they represent), is that they simply express a fast rate of deformation. Even mud when pulled quickly will fracture, so it seems rational to regard that the rapid application of stress to any normally ductile viscous (or brittle) material will respond (within reason) in a similarly brittle way. And if you have any doubt about the fast rate of deformation, just consider the number of earthquakes around the Pacific every day (well, ..month, according to the image above). On the scale of geological time this is a *horrendously* fast rate. Even on a daily rate it is horrendously fast (how fast do your fingernails grow?) Anybody who thinks those earthquakes represent the build-up of stress over geological time just needs to ask anybody living around the Pacific, where Earthquakes are going off every day, especially the Indonesians who live on the cusp of global hemispherical twist, the devastated battlefield of Pangaean crustal severance.
Simply from a conceptual viewpoint earthquakes in a zone that we know is deforming quickly (image above) is far more likely to be linked directly to rates of deformation, than they are to be linked (in a crust that gets hotter with depth) directly to coldness. Hot enough to give partial melting, but cold enough to cause sinking? I think not (!) What about you? Besides there is not one earthquake, and never has been in the time I have been looking at that map, on the cold ocean floor itself away from the ridges. They're all on the transform adjacent the ridges or on subduction zones - the hot parts. So what's all this about 'cold' (and brittle)? Hot and brittle, ..I think is more likely (= fast deformation).
The term "cold subducting slab" is therefore little more than meaningless pterospeak, no more than supposition, but most of all it is code to support consensus: "I speak the lingo. I am one of you."
To understand the extent to which this meaningless pterospeak dogma has permeated understanding of plate tectonics we can juxtapose the quotes at the top of the page with others of teaching institutions today, which supposedly carry authority in this matter of subduction - which as things stand today is the crux of the Earth Sciences. All consensus publications (there are no mainstream others) are written around this fundamentally wrong 'cold slabby' concept of plate tectonics. In them you can see the extent to which the assumption of subduction underpins the position of plate tectonics. There is nothing factual about it.
"The size of the Earth has not changed significantly during the past 600 million years, and very likely not since shortly after its formation 4.6 billion years ago. The Earth's unchanging size implies that the crust must be destroyed at about the same rate as it is being created."
" If the Earth was not to be blown up like a balloon by the continual influx of new volcanic material at the ocean ridges, then old crust must be destroyed at the same rate where plates collide. The required balanced occurs when plates collide, and one plate is forced under the other to be consumed deep in the mantle."
"Working together, the spreading and subduction processes make for a great global balance (the earth is really into balance and is good at it - it's been practicing for a very long time). New basaltic crust is produced at the spreading centers, and then consumed (or eaten, if you will) at the subduction zones, where it is purified and converted into granite. This is a real good thing, too! Without both processes the earth would either expand like a balloon (and pop?), or it would eventually eat itself into non-existence. Either result would cause problems for those of us destined to exist on its surface."
"Either result would cause problems for those destined to exist..."? Well, we can't possibly have that, can we (problems in science)? That wouldn't do at all. That is why the subduction myth, as it was originally formulated (top of page), and which has transformed what used to be a subject with a highly empirical quotient, into *Junk Science*, is perpetuated. It avoids problems in science.
Find more about "assumptions of Plate Tectonics"
Fig.3. The necessity for the 'convenient assumption' of subduction.. ..Is the need for the removal of a hypothetical Panthalassa to make way for the present ocean floors. If there were no Panthalassa (below the picture) the continents would never separate. An imaginary Panthlassa is necessary for subduction to work. . (Image courtesy of Nasa.)Or you could animate it and make it look nice, but it still doesn't work. There needs to be a continent riding on the oceanic lithosphere (green stuff) in order that continents can collide and mountains "arise", otherwise Plate Tectonics would never work. But continents sitting on top of oceanic lithosphere is a contradiction anyway; continents sit on continental lithosphere, not oceanic lithosphere. See how dopey and contradictory all this Plate Tectonic stuff is? Why would anybody want to learn it?
(Why would anybody want to teach it?)
(Classroom mayhem.. that's what they're asking for, if students have any sense..)
[Hey, .. there's nothing wrong with the sea-floor spreading (making the Earth bigger), .. it's the subduction (making it smaller) turns it into the nonsense of Plate Tectonics.]
|"..If (as seems certain)... the Earth is neither expanding nor contracting, the net rates of spreading and subduction over any great circle on the Earth must be equal, and the pattern of plates and late motion must adjust to keep this so."|
"If, .. (as seems certain... )" ... Yes? but.. (Now then..)
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