Advanced Plate Tectonics

Oce 661 so where do we stand with so convection and

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Unformatted text preview: tead. Attempts to quantitatively fit this change to the collision of India with Asia, while the timing is ok, have otherwise not fared well (Richards and Lithgow-Bertelloni, 1996). OCE 661 So where do we stand with So convection and plate tectonics. And some things don’t work quite so well: so By the way, what are hotspots anyway? Where do they fit By in? Compatible in mid plate settings, but not so much in ridge centered settings, and where downwelling zones cross them (Yellowstone hot spot). cross For that matter, how can slab pull drive India through Asia? For Will it stop? Models don’t predict plates at all, or “plateness”. Other features are required, such as strong interiors and weak edges (plate evolution) edges OCE 661 So where do we stand with convection and plate tectonics. And some things don’t work quite so well: so 1) One of the biggest missing pieces, is toroidal motion, that One is rotations about vertical axes and the attendant strike slip motion. This may account for as much as 50% of plate kinetic energy. Where does this come from? a) You can impose plate shapes or fault systems to a) You generate toroidal motion (not very satisfying) generate b) The existence of such motion may minimize energy The dissipation in 3D convection models, and thus be favored energetically. c) All of these problems require very soft plate c) All boundaries, and seem to require non Newtonian lithospheric layers, i.e. strain-softening non linear behavior. This means the greater the force, the weaker it gets. Can you think of an example? OCE 661...
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This document was uploaded on 01/26/2014.

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