Indian Plate collides with Asia?

Nonsense 3 - Himalayan push or pull?
(..Laying this Emperor dude bare...)

Fig.1. The contradictory push - pull of Plate Tectonics. The Indian plate collides with Asia (green arrow) squeezing Asia "as in a vice" and pushing up the Himalayas while the Pacific plate (red arrow) collides with Asia and drags off the chain of islands, creating 'back-arc basins'. The alternative here is gross dilation of the mountain belt (brown) by the intruding Pacific diapir which has ruptured this mega-foldbelt, dilated it, and scissored it open to spread the American Cordilleras about the Caribbean Pivot (purple) by 180 degrees.. (Blue line = so-called 'subduction' zone, not shown for the Eastern Pacific)

The nonsense refuted here lies in the explanation Plate Tectonics gives for the relation between so-called subduction along the Himalayan front, and that along the Western Pacific margin. In the case of the Himalayan front, India, carried 'piggie-back' on the Indian plate, is supposed to push into Asia, compressing it as in a vice and forming the folds of the Himalayas and causing the uplift of Tibet ("far-field tectonics"). In the Western Pacific however the Pacific plate moving westwards, is supposed to be doing exactly the opposite - pulling the edge of the Asian continent off to form the so-called 'back-arc basins' of the Pacific.

How so? The difference according to Plate Tectonics is whether or not there is continental crust sitting on top of the moving plate of oceanic lithosphere. If there is, then this can be used like a battering ram to crumple any other crust that gets in its way. If there isn't, then the lithospheric plate exerts an extensional force on the buttress it is colliding with by a process called "rollback", and drags chunks off it, creating basins in between

Now, remember the plate is not moving like a barge, but is really stationary. Movement is like caterpillar tracks of a bulldozer that are stuck in mud, going round and round, but going nowhere. Or like an escalator. But anything on top of the tracks, ..like a continent (say) (or people), is carried along and plastered up against any resisting buttress that may get in the way - like another piece of continental crust. But the escalator (convection cell with frozen skin ('plate') on top) is not moving around the shop.

And that, exactly, is how mountains (Plate Tectonic style), are made - the crush zone at the top of the escalator where everything piles up, but the escalator (plate) is going nowhere, ..only round and round.

And if there is no continental crust on top of the moving plate? Then instead of the crushing and crumpling the buttress to kingdom come, the oceanic lithosphere pulls chunks of continent right off ! How come?

Well, ...it goes like this:- the caterpillar track of the oceanic lithospheric plate turns, moving the piece of continent on top along till it meets the continental lithospheric plate, which then forces or pushes the oceanic lithospheric plate down. As the slab of oceanic lithosphere goes down it creates a kind of 'suck' - like the Titanic when it's sinking, and the water gets pulled over the disappearing stern, ..so a piece of the buttress gets pulled off and dragged over the slab as it goes down, creating the back-arc basins of the Western Pacific.

The process is attributed to rollback, where the descent of the downgoing slab causes the bend in the downgoing lithosphere on the oceanic side to migrate away from the buttress back towards the spreading ridge, which increases the migration of pull-apart basins of the Western Pacific (there are no others) oceanwards.

Now just a minute, ...the continental lithosphere is pushing the mantle slab down, and the downgoing mantle slab causes rollback that pulls chunks of continental lithosphere off?

I don't know about you, but that sounds to me like a recipe for runaway 'pulling-off' (of the crust), and runaway slab-sinking too, ..more than a perpetual motion machine in fact !

It is supposedly this 'sinking slab' that drives Plate Tectonics. All incredibly dynamic stuff, and all consequent on the continental lithosphere pushing the oceanic lithosphere down.

So, ...what? Just by sitting there, doing nothing (except minding its own floating business), the continental lithosphere pushes the oceanic lithosphere down, causing the oceanic plate to subduct which then drives the Earth's deformation? Are they kidding? (Nope.)

So, ...how about wiggling your fingers in the holes in the Emperor's old clothes - and giving them the Big Rip? - Wiggly fingers of the world, ...unite!....lay this Dude bare!

Got a question?
Ask a Guru

| frontpage | nonsense | expansion |