Re: Where did the extra mass come from?


"Florian" <auxotectonics_deletethis@xxxxxxxxxxxxxxxxxx> wrote in message
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George <George@xxxxxxxxxx> wrote:

"Florian" <auxotectonics_deletethis@xxxxxxxxxxxxxxxxxx> wrote in message
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George <George@xxxxxxxxxx> wrote:

Jeeeezzzz. Do you remember that matter acumulates inside the planet?
That is how pressure build up.


So gravity has no effect, and can be completely ignored in your
scenario?

what are you inventing again?

Answer the question.

That question does not make sense as gravity is always part of the
system.

So you admit that gravity can overcome buoyancy. That's great. Then explain
why gravity cannot overcome buoyancy at subduction zones.

Also answer this one: Where does the matter come
from?

cranky question.

Valid question.

Look at that figure again:

<http://nachon.free.fr/overthrust/Tibet-flow.jpg>

It was published in Science 2 weeks ago:

The Geological Evolution of the Tibetan Plateau Leigh H. Royden,
Science 321, 1054 (2008);

Since I currently don't have access to that publication

Go to a library. There is certainly one nextdoor.

Why? I'm not your secretary.

Lazy moron.

You make a claim on usenet, you own it. Post
your evidence or quit wasting bandwidth.

Idiot. My claim is supported by a reference. A reference in a peer
review paper is a way for us, scientists, to support a claim. You would
know it if you were one.

You claim to be supported by ONE person, the conclusions of which are
questionable, at best, and who would likely correct you in many areas, where
he in this conversation. Plate tectonics is supported by thousands of
geologists published in dozens of publications. Next.

[...] You can't get an andesite from peridotite or any other mantle
rock because it is silica poor.

Fractional crystallization enriches the magma in silica, resulting in
low density rocks. That's why it is not obvious to get systematically a
positive anomaly at arcs.

Peridotites do not undergo silica enrichment because they are
ultramafic/silica poor (dunite, for instance, is 90% olivine). However,
basalt, which is also poor in silica but more enriched relative to
peridotite, can undergo silica enrichment to form andesite, as I've pointed
out half a dozen times.

Umm, citation from an outdated textbook? Try a paper written in 2004:

Try a 2006 paper:

"Kinematically, subduction rollback implies that the volumes left in
the
hangingwall of the slab have to be replaced by a horizontal mantle
flow,
whether this is a consequence or the cause of the retreat (Doglioni et
al., 1999). However, in order to allow the slab to move back, the slab
retreat needs the mantle in the footwall of the slab to also move away
in the direction of the slab retreat, regardless whether this motion is
generated by the slab pull or is an independent mantle horizontal flow.
But the energy required to push the mantle forward is much greater than
the slab pull can effort."

<http://tetide.geo.uniroma1.it/sciterra/sezioni/doglioni/Publ_download/W
hatMovesSlabs.pdf>

That is a very interesting paper.

yep, bye bye roll back.

I note, first of all, that you apparently
have given up on "upduction", [...]

Wishful thinking.

Your hand says no, but your mouth says yes, yes, yes!

since you are presenting me with a paper that
supports subduction and plate tectonics. Secondly, there is this from
the
paper:

"It is obvious that convection occurs in the mantle, not only from
modelling, but also from the kinematics of plate boundaries, where mantle
uprises along ridges [...]

evidence of surfaceward displacement: totally expected from inside
growth. Learn the difference between upwelling at ridges and upwelling
at upduction.

The rest is refuted when one know how determine absolute motion at both
side of a trench.

So you are in disagreement with the author's conclusions (the author YOU
cited), despite the fact that he conducted the work, and published it, and
you've not published anything?

George


.

Relevant Pages

  • Re: Where did the extra mass come from?
    ... So gravity has no effect, and can be completely ignored in your scenario? ... hangingwall of the slab have to be replaced by a horizontal mantle flow, ... whether this is a consequence or the cause of the retreat (Doglioni et ... However, in order to allow the slab to move back, the slab ...
    (sci.geo.geology)
  • Re: Where did the extra mass come from?
    ... So gravity has no effect, and can be completely ignored in your scenario? ... so where are the gravity anomaly maps that show widespread mantle ... However, in order to allow the slab to move back, the slab ... uprises along ridges and the lithosphere sinks along subduction zones. ...
    (sci.geo.geology)
  • Re: Slab of sunken ocean floor found deep within Earth
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    (sci.geo.geology)
  • Re: Slab of sunken ocean floor found deep within Earth
    ... Earth's core meets its mantle, lies a massive folded slab of rock that ... The slab, which sank beneath North America some 50 million years ago, ... holds important clues as to the behavior and composition of the deep ... could shed light on large scale circulation of rock in Earth's interior, ...
    (sci.geo.geology)
  • Re: Slab of sunken ocean floor found deep within Earth
    ... Earth's core meets its mantle, lies a massive folded slab of rock that once ... important clues as to the behavior and composition of the deep interior of ... Earth and it could help explain how surface features such as volcanos and ...
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