Re: ALL the oceanic crust is recycled in 180 My: unrealistic


"Florian" <auxotectonics_deletethis@xxxxxxxxxxxxxxxxxx> wrote in message
news:1in7w8v.1ohhdokc4d7hN%auxotectonics_deletethis@xxxxxxxxxxxxxxxxxxxxx
George <George@xxxxxxxxxx> wrote:

Since there is no such beast, you have no argument.

idiocies from an ignorant goose:
<http://www.sciencemag.org/cgi/content/abstract/276/5310/240?ck=nck>

"Given reasonable H2O abundances in Earth's mantle, an H2O-rich fluid could
exist only in a region defined by the wet solidus and thermal stability
limits of hydrous minerals, at depths between 90 and 330 kilometers. The
experimental partial melts monotonously became more mafic with increasing
pressure from andesitic composition at 1 gigapascal to more mafic than the
starting peridotite at 10 gigapascals. Because the chemistry of the
experimental partial melts is similar to that of kimberlites, it is
suggested that kimberlites may be derived by low-temperature melting of an
H2O-rich mantle at depths of 150 to 300 kilometers."

Two issues. First "given reasonable H2O abundances". Define "reasonable
with regard to this statement". Secondly, the experiment is showing how
material is becoming more mafic with increasing pressure, not less mafic
with decreasing pressure. Third, how is this evidence that "deep mantle"
material is upwelling beneath subduction zones?

And it doesn't matter whether the work is 16 years old or two
months old. The chemistry is still as valid today as it was then.

It is important because new pathwys are found.


That is not a conclusive argument. Evaporites are also present at the
place of former epicontinental seas.

The Gulf of Mexico is not an epicontinental sea, and yet it has lots of
evaporites. The Baltic and the Mediterranean Seas are not epicontinental
seas and yet they are loaded with evaporites. Floppy, the presence of
evaporites is not a definitive argument that a sea is epicontinental.

You're the moron infering from what I wrote that evaporite would be
restricted to epicontinental seas.

You brought it up, floppy.

The basement of the basin is a rift composed
of basalt. Same for the Illinois basin and the Appalachian basin.

That's good enough to me. Those are exactly the kind of narrow oceanic
basin that developped by strechting of the crust as Earth was slowly
growing. At that time, these basins never developped into 10000 km wide
ocean, simply because the Earth was much smaller and grew at a slower
rate. There were only "aborted ocean". The global oceanization of Earth
is a very recent. Less than 200 My old.

Large sinistral strike-slip faults in Scotland suggesting a total
displacement of around 1500 km indicate that the Iapetus ocean was at
least
that large.

Large or long?

Wide.

The Tethys Sea was pretty big. And Panthalassa was huge.

Tethys and Panthalassa are assumed to be large because it is also
assumed that the globe hs a constant size.
Garbage in garbage out.

No, they are measured based on field data to have been large, in
Panthalassa's case, VERY large.

list of ancient oceans that apparently, according to a non-geologist
(you)
never existed:

Liar. All of these oceans existed, but they were narrow.

Really? Where is your field data that backs up that claim? And Floppy,
since EE claims that all of the continents were once together and made up
the sum total of the Earth's crust "prior to expansion", then these ancient
oceans shouldn't exist at all, and in fact, this has been the argument of
EEers for many years. I guess you didn't get the memo.

George


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