From: Glenn Morton (glennmorton@entouch.net)
Date: Sun Oct 05 2003 - 23:00:38 EDT
>-----Original Message-----
>From: allenroy [mailto:allenroy@peoplepc.com]
>Sent: Sunday, October 05, 2003 9:45 PM
>I suspect it is quite high (i.e. whichever way means they will not
>move past
>each other easily)
Correct, something like 10^22 poise, with water at .01 poise.
however, the model does not require the crust
>the slide over
>the mantle like a ski over snow. Rather the athenesphere, which
>is the most
>plastic layer of the mantle, flows due to the sinking of the
>oceanic crust into
>the mantle. As it circulates, it pushes (drags) the plates around.
Think about it Allen. If the circulation moves with the plate, then the
hotspot moves with the plate also and doesn't string out a lot of volcanoes.
Not to mention you have to have 4000 km of differential motion in a few
years with that kind viscosity. It simply won't happen.
>
>> You have no coherent theory until you explain what the motive force
>> was. runaway subduction won't work in my mind because the
>tensile strength
>> of the oceanic crust appears to be too small to allow such accelerations
>> required by Baumgardner's theory. Got another one?
>
>With the athenesphere pushing (dragging) the oceanic crust around,
>the tensile
>strength of the crust is not a major factor.
But as I mention, the hotspot will move with it thus not move relative to
the crust. This theory won't fly.
The subduction is due to the
>weight of the crust sinking into the athenesphere mantle because
>of a change in
>viscosity of the mantle. That sinking sets up a current which
>moves the crust
>over to the subduction zone like an escalator. Tensile strength
>of the crust
>would likely slow the process down.
The gravitational pull due to a sinking slab is too small to pull the crust.
Many people have calculated this over the years.
>> Given that we don't see any change in chemical composition among
>the islands
>> and given that we don't see any change of chemical composition
>in the mantle
>> underlying the pacific (this would be seen by velocity variations in the
>> speed of sound) what evidence you you have to support this claim?
>
>You, yourself, listed 40 different measurements of chemical
>changes from island
>to island. It would be impossible to have different computed ages, if each
>island had exactly the same chemical mixture.
But Allen, these are changes due to the decay of radionuclides after they
come to the surface. it isn't the same as merely a chemical change. During
volcanism, in general the argon escapes leaving potassium to decay to argon
which then builds up in the volcanic rocks. Because most of the argon
escapes (no it isn't 100% certain) The chemical change is merely the build
up of Argon. That isn't the type of chemical change you are thinking of, I
bet. Why would argon be preferentially trapped 4000 km from Kilauea and
preferentially released at Kilauea? Makes no sense, Allen.
>The difference between you and I is that you believe that these measured
>differences in isotopes from island to island are the result of
>long ages of
>time. I believe that these differences are simply due to changes
>in the make up
>of the source material over a short time.
The gaseous argon wasn't in the source material. When the lava comes to the
surface it escapes to the atmosphere.
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