....Scale: the fatal flaw of plate tectonics
                 (The error in scale is the scale of the errror)

 
Plate tectonics sees ridges, transform faults and subduction  zones as having equal same-scale status.   There is no real reason for this, just an a priori assumption that they 'look like it'.  And it's true, so they do - look like it.   But  the scale that plate tectonics is looking at is, in its entirety, wrong.  This error of scale is the crux.   Plate tectonics opts for 'small', when the elements involved indicate the true scale is 'big'.

In conceiving of the Eath's crust being broken into a "number of plates that move independently about" (a number is put on it - eight or eleven or twelve, depending), plate tectonics blinds itself to the fact that the spreading ridges that form the principal plate-boundaries are actually continuous.  Meaning that there is really only one plate.

Well of course, it is not blind to the fact at all, because that's the way they are typically described in sites for schools ("..the ridge goes around the Earth like the seam on a baseball"), it's just that it is convenient to describe it like this sometimes (for example in schools), and convenient to ignore it at other times (in professional publications).   The first is a useful analogy to describe the actual distribution of the ridge at the present time, whilst the second is convenient when it is necessary to employ the model  to describe imagined independent plate movements in the past (plates that "move past" each other (see also), and plates that move independently).

So, ..what? Plates that move independently past each other?

Tosh and doublespeak.   If the ridge does go around the Earth like the seam of a baseball, with transform faults like stitching,  and the plates are contiguous with the ridges, then the ridges are something that all  plates have in common, so to that extent they are not independent.  That simple fact of commonality at the global scale entirely negates the asserted independence of so-called 'plates'.  As well as that, beyond the limits of the active sectors of the spreading ridge (those little white lines at the spreading ridge in the figure here) the 'plates' are all locked as one.  There *is* (and can be) no "moving past")

Now the crust is assuredly broken, but the breaks are not severed to allow independent movement when they are linked by the 'seam of a baseball'.  The whole 'skin' of dismembered crust still hangs together.  Without rotational dislocation, separation does not result in any degree of 'independence'.    Moreover ridges are fixed with respect to the so-called upwelling cell.  A boundary to a plate (such as a ridge)  that stays fixed when the plate itself 'moves' is hardly a boundary to the moving plate.  It is a boundary of something, certainly, but not a boundary of a "moving plate".   It is in fact the locus of global  ocean-floor spreading/ growth, not one side of a "moving plate": ..... 'growth' is not 'movement'.

Another way of looking at this is how transform faults are described in the model.   'Transform faults' are also described as plate boundaries, but only plate boundaries for the ridge-to-ridge sector -  i.e., only a very small part of the length of transform faults.  Beyond that they are called 'fractures' which show virtually no seismicity, and no difference in crustal movement across them.  Across these transform strips the mantle plate is all effectively locked as one - one large plate.   Again, hardly indicative of "independent plate movement"!

But (yet another way of looking at it) let's say for the sake of argument that there is "movement" at the ridge and that the whole ocean floor/ mantle crust is moving towards subduction zones. How does this happen when subduction zones take up less than half the equivalent length of the spreading ridges?   Either the plate must be descending at twice the rate of ridge production, or the Earth is growing anyway.   Since it is axiomatic in plate tectonics that the Earth cannot be growing, then the rate of subduction relative to ridge accretion must be in proportion to their difference in length.  This means that, considering the actual geometry on the actual surface of the Earth,  ridge movement not only equates directly with subduction 'down the front' of the subduction zone, but subduction 'down the back' as well.  For example Atlantic spreading is supposedly accommodated westwards down the acutely-angled (back) side of the American subduction zone fronting the Pacific, whilst 'normal' (Pacific) subduction is proceeding from the Pacific side..  Also eastwards,  Atlantic subduction cannot occur till the plate gets to the Asian region, with the problem that the Red Sea - Indian Ocean spreading ridge is in the way.  On the Northern Atlantic side subduction cannot occur until the (again) acutely angled, back side (eastern side) of  Western Pacific subduction is reached.   If spreading is occurring equally at the ridge, and the Earth "cannot be getting bigger (otherwise it would be blowing up like a balloon and everybody knows this cannot be etc etc., )",  then what so-called 'friction' is being generated in the subduction zone when both sides are descending at the same rate, as they must be if mantle generation is equal on both sides of the ridges and magnetic striping confirms is the case?   None that counts.   This makes a mockery of  the 'Fiery Ring of the Pacific' being a zone of friction generated by subduction.  And if opposite sides of subduction zones are descending at different rates (to give the friction we do see in the seismicity),  how is this difference translated back to the ridges so that magnetic striping at the ridges remains symmetrical?

The short answer is it's not and it can't,  and therefore from a conceptual point of view 'subduction' as it is portrayed by plate tectonics is invalid.  Certainly there is a zone of sorts, but it is not one of subduction.   They are instead overriding zones, whose relationship to transform faults indicates they are an expression of deformation related to the planet's spin.   For plate tectonics to substitute 'overriding' for subduction is either gross and purposeful obfuscation, or a graphic illustration that its proponents do not recognise the conundrums inherent in their own model,

It is intolerable for plate tectonics to cite (as it does) 'overriding' as articulation of plate tectonics.  Although there is no actual mechanical difference at the going-down interface, subduction is not overriding.  Subduction means 'going down' after the manner of convection, moving one plate under the other.  Overriding means crustal decoupling and the moving of one plate over the other, which has a symmetry related to the Earth's spin and increasing size - or more exactly a 'helical' symmetry that would appear to relate to some progressive change in the Earth's spin.  Plate tectonics' use of the term 'overriding' is in recognition of crustal movements shown by gps measurements, which in itself substantially lessens the validity of subduction: the Atlantic Ocean is not a 'back-arc basin' of the Eastern Pacific, unless the point of scale in the title of this page is conceded.

This is not rocket science.  If ridges and transforms jointly evidence a single global plate (stitched like the seam of a baseball - as described in class) then from this standpoint alone plate tectonics simply does not apply.   If subduction is equated with overriding, and the role of transforms recognised in this, then there is implied removal of the fundamental principle of convection.   And if this overriding is most explicable in a context of spin and enlargement, as global architecture indicates it is, then subduction (plate tectonics) is entirely negated.   And if subduction is negated, then there are no grounds for plate tectonics at all.

So, is the Earth "divided into a number of plates that move independently about"?    It might sound good as an assertion, and 'plate margins' might be drawn on a map, but the considerations above imply they have no validity whatsoever.  There is only one plate: the mantle.  'Plates' (plural)  are pure shibboleth.   What plates?  How?  Where?  Why?   There are no answers to these questions, and it is not possible to address them without using the word-strings "how plates form"; "how spreading ridges form"; how transform faults form"; how subduction zones form", yet in the more than three hundred and eleven thousand sites currently on the web,  a google search on "plate tectonics" plus the terms below returns virtually zero entries.  How can this be?    It can be only because the word-string is not used, because no-one is asking the questions, because there ARE no answers within the framework of plate tectonics.  Firstly, subduction zones do not conceptually exist as even the most peremptory considerations above will show; sections purporting to illustrate it must be interpreted otherwise (e.g. as overriding)  and secondly, answers to questions regarding the other two are manifestly not to be found within the scope of plate tectonics.
 

"Plate tectonics"  =  311000 google entries
"How spreading ridges form"    =  1 entry (this site)
"How transform faults form"     =   2 entries
"How subduction zones form"   =  1 (this site)
  (January 03 2005)