CompuServe Messages

Subduction & Ocean Basin

    29-Dec-94 23:03:13
Fm: Doug Mitchell 70621,702
To: Kamron Kirkconnell 73740,2246
Hi, Kamron– >>The very nature of upwelling or moving up should dissipate any power the magma would have unless the pressure was contained…it could offer no power to push. Since you have already claimed this, and I have offered a counterexample, this is "proof by assertion". Have you any evidence? You could say the same about water, but it would not be true as evidenced by my freezing example. I suspect you are correct in this statement, but do not take it as a given. >> Even if this condition existed below the plates… and there was a wide area laminar flow the fragile crust would show more evidence of deformation around the subduction areas. More evidence than ocean trenches and volcanoes with a strong tendency to be "downstream" of the trenches? I think this depends on how frictionless is the connection between lithospheric plates and mantle at the asthenosphere; that is why I had to specifically specify mountain roots to give the convection currents something to "grab". Until someone can spend time making measurements down there, this seems to be another adjustable parameter that neither confirms nor denies the theory. I am not equipped to discuss your geographic details while traveling; perhaps I will have something to say when I get home to my references, in a bit over a week (best guess). >> The plates _both_ shifted….. without a trace of the adjustment farther back from the rise in either direction. How can this be possible? Most if not all faults come to an end, and the same question applies to all those ends. It seems no better explained by your theory than by plate tectonics. >> why did the convection current upwelling areas shift with the rise when the shift fault movement occurred? We already discussed that, why are you repeating it? Perhaps the rise was forced to move by a change in the current position rather than vice versa, or perhaps the current is wider and the rise is atop the unmoved current as much in the new position as the old. –Doug –Doug