....Where
Plate Tectonics fails ...
(...is in Subduction... the forcing down of the oceanic plate by the continental lithosphere...)
....Where
Plate Tectonics fails ...
(...is in Subduction... the forcing down of the oceanic plate
by the continental lithosphere...)
| "...Because of the central role that subduction plays in the solid Earth system, as well as its role in maintaining equilibrium between the mantle and the hydrosphere, understanding and teaching how subduction zones operate is a scientific challenge of the first importance." .. Wiki |
Wikipedia:- " A subduction zone is an area on Earth where two tectonic plates meet and move towards one another, with one sliding underneath the other and moving down into the mantle, at rates typically measured in centimeters per year." (Wiki)NASA:- "These (subduction zones) are plate margins where one plate is overriding another, thereby forcing the other into the mantle beneath it. "
USGS:- "The subduction zone is the place where two lithospheric plates come together, one riding over the other."In the best tradition of thieves and robbers the USGS and NASA are 'shooting through' with the nomenclature booty, leaving the Wikipedia holding the subduction baby. The Wiki - perhaps not the most authoritative on the subject since it is written (and edited) by you and me, but by far the most sincere in adhering to the meaning of the word, ..'sub', meaning 'under' or 'beneath', ... and 'duct' meaning 'carried' (subducted = carried beneath) openly maintains the role of convection in Plate Tectonics. Not so either the USGS or NASA whose rephrasing of subduction ('carrying' down') in terms of overriding, sneakily allows them to speak with a forked tongue, one fork (the one described by current illustrations on their respective sites) allowing them to maintain the myth of convection, whilst the other fork allows them to position themselves for the next seismic shift in the Plate Tectonic goalposts along lines described on this site. 'Overriding' carries no connotation of convection or subduction, but does indeed carry a connotation of crust - mantle dislocation, which when tagged to the latitudinal symmetry of pivotal opening of the Atlantic about the North polar region, and so-called 'flat subduction' (a contradiction in terms by any standards) of the Western Americas in relation to the Pacific, is clearly related to the Earth's spin.
So, ..thieves and robbers? (Something here about that bit about later generations dusting off and claiming as their own the earlier ideas they strenuously rejected, and why real change virtually never comes from within the mainstream.) Well, ..Possibly, ..except for that other bit about subduction zones happening where the crust pushes the mantle plate down which reassures us that they really are nuts. Just in case you're not sure what they're saying here it goes like this:- 1. The crust floats on the mantle (because it's less dense; 2. the crust (which is therefore floating) pushes the mantle down (on subduction zones); 3. subduction drives plate Tectonics; 4. Plate Tectonics is the mechanism causing crustal deformation (mountains etc). So, ..just by sitting there doing nothing except floating on the mantle, the crust is causing its own deformation.... On this basis alone (for this is the consensus position) any attempt by Earth scientists to get ahead is laughable. They can steal what they like. They're sure to end up in jail, ..without even passing 'Go'.
| Professor
Seiya Uyeda (Tokai University, Japan), a world-renowned expert in plate
tectonics, concluded in his keynote address at a major scientific conference
on subduction processes in June 1994 that "subduction . . . plays a more
fundamental role than seafloor spreading in shaping the earth's surface
features" and "running the plate tectonic machinery." The gravity-controlled
sinking of a cold, denser oceanic slab into the subduction zone (called
"slab pull") -- dragging the rest of the plate along with it -- is now
considered to be the driving force of plate tectonics." http://pubs.usgs.gov/gip/dynamic/unanswered.html
"With Seiya Uyeda Don carried
out the first formal inversion of tectonic plate speeds for the forces
that contribute to plate motions. That work demonstrated clearly that plate
speeds are controlled by plate subduction, and that the driving force of
sinking lithospheric slabs is nearly fully opposed by resisting forces
at overthrust plate boundaries and viscous tractions on the subducting
plate." http://www.geosociety.org/aboutus/awards/05speeches/day.htm
|
(Include quotes here along the lines of NASA and the USGS about the crust forcing the mantle down..) (Fry them. )
(Begin:-)
| "Subduction zones - are
destructive zones where oceanic crust is forced down into the mantle
as two plates converge. This is happening beneath British Columbia as the
Juan de Fuca Plate is forced beneath the North American Plate. " http://www.em.gov.bc.ca/mining/geolsurv/Publications/InfoCirc/IC1995-07/tectonics.html
"The oceanic material is forced down into the mantle because it is more dense than the continent. In fact, the reason the continents are so much older than the ocean floor is that the continental crust is composed of material too light to sink into the mantle." http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/plate_tect01.html "Subduction is the result of two tectonic plates converging, as one plate, typically the oceanic plate, is forced down or subducted under the less dense continental plate.... <snipped> ...The gravitational pull of the denser oceanic plate drives the subduction." http://www.utexas.edu/tmm/npl/mineralogy/Mineral_Genesis/index.htm "When continental and oceanic plates collide the thinner and more dense oceanic plate is overridden by the thicker and less dense continental plate. The oceanic plate is forced down into the mantle in a process known as "subduction". As the oceanic plate descends it is forced into higher temperature environments." http://geology.com/nsta/convergent-plate-boundaries.shtml "Most tsunamis are caused by earthquakes generated in a subduction zone, an area where an oceanic plate is being forced down into the mantle by plate tectonic forces." http://geology.com/articles/tsunami-geology.shtml "Island arcs are formed by
subducting, converging tectonic plates. When one oceanic plate meets another,
the denser plate is forced downward into a deep ocean trench."
"A region in which one crustal
plate of the Earth is forced down (subducted) beneath another, and
moves down into the mantle where it is eventually assimilated. Present-day
subduction zones occur around the margins of the Pacific Ocean at the sites
of deep ocean trenches, and are associated with earthquake and volcanic
activity and the formation of island arcs such as Japan and the Aleutian
Is.
When two plates collide,
one is forced down beneath the other into the mantle (the plastic-like
layer between Earth's crust and core that flows under pressure), creating
what geologists call a subduction zone. Because subducting slabs are colder
and denser than surrounding mantle material, they tend to sink like a lead
ball in a vat of molasses.
etc.. |
The crust forcing the mantle down? It's laughable. But no, they're not joking. It's the only way in their model that they can rationalise subduction on a line against continental margins. How else? Of course it does occur to them that the model might be wrong. But it's no big deal since everything else they 'rationalise' in Plate Tectonic theory is nonsense anyway. Wrongness or rightness is not the point. It's a consensus thing, ...and paying a lot of mortgages. That, of course, is not the proper way to express this sentiment. It must be framed in the context of professional competence, so it goes like this:-
| "Even experts have had trouble
teasing out the exact mechanisms. <...> It's been known
that slabs (portions of plates that extend down into the Earth) drive convection
in Earth's mantle, and ultimately the motion of the surface plates, but
it hasn't been well established exactly how that happens -- the ideas have
been fairly vague,"
http://www.spacedaily.com/news/tectonics-02k.html |
Trouble teasing out mechanisms? Well, no wonder when there is such conflicting opinions as "It's the continental lithosphere forcing the mantle (oceanic lthosphere) down that drives Plate Tectonics, ...and that "It's the subducting slab itself that drives subduction as the cold slab descends into the hot interior and undergoes a density change from basalt to eclogite"
| "..Eclogite typically results
from high-pressure metamorphism of mafic igneous rock (typically basalt
or gabbro) as it plunges into the mantle in a subduction zone ...
en.wikipedia.org/wiki/Eclogite - 36k - Cached - Similar pages - Note this " |
| "...His Indonesian knowledge
led to his elegant analysis that subduction drives plate tectonics, and
that top-down cooling of oceanic lithosphere produces the density inversions
that drive subduction."
http://www.geosociety.org/awards/07speeches/sgt.htm |
Get it? - the mantle gets denser because of cooling,.. and also gets denser because of heating. Since the only difference here is whether the mantle is at surface and flat (spreading), or going down and steep (subduction), one is left to infer that flatness and steepness are arguably the controls which determine whether the mantle gets denser by heating or by cooling: if it's flat and going along (spreading) then it gets denser by cooling; if it's steep and going down (subducting) it gets denser by heating. To which the obvious corollary is that if it's steep and coming up (as under a spreading ridge) it gets less dense by cooling. Which, it could be argued, is why it rises. Well, why not? If it can get more dense by heating, surely it can get less dense by cooling?
Subduction occurs as the corollary of spreading ridges - with exceptions being all around the Atlantic Indian and Southern Oceans - quite a large slice of ocean margin by any account. Which leaves the Pacific. But the dimension of the Pacific margin is only about half that of the length of the spreading ridges, which means that the rate of Pacific consumption (subduction) is about twice that of creation of ocean floor, ..i.e., the downward cycle of convection is twice the rate of upwards convection, and even more than that if we consider that the Western Americas are overriding the Pacific rather than subducting. (Google up "flat subduction" - a contradiction in terms)
Secondly, if the oceanic lithosphere is being returned to the mantle in this way, commensurate with uprise and ridge creation, then the ocean floors would never open in the first place. Now, ..would they? The destruction of ocean lithosphere in subduction zones would be simultaneous with creation of mantle crust at the ridges - and the ocean floors would never open. You don't have to be a rocket scientist to see that!Thirdly, a couple of hundred or so earthquakes going off every week around the Pacific i.e., brittle failure every day for the last few hundred million years has reduced the brittle crust/ mantle interface here to effectively rubble. It's just shameless nonsense to suggest this pile of dross is a coherent slab that sinks and drags the Earth's surface around with it as it does so.
Conclusion:- On simple prima facie grounds subduction is rubbish. And with no subduction there is no compensation to ridge creation, and the only bit of Plate Tectonics that has relevance is the emplacement of the ocean floors as the continents separate - which is ... the bit we can see, ..which is, ... (wait for it), ....Earth Expansion.
Crazy Platies. Nuts. And afraid. Afraid to venture into the unknown...
....Consensus animals... Why?
Because thinking for yourself is professional suicide