Hi, all -
With Matt Morgan's help, we've just finished a paper
on the Putorana rock, and it should be published in
July (?) with the Meteoritical Society meeting abstracts.
The paper is bigger and more formal than the article(s)
in Meteorite . If you'd like a preprint, send me your email
or postal address!
Personally, I'm not real keen on the Putorana iron coming
from the Earth's core. It seems like an awfully long way for
heavy stuff like iron metal to rise (or be carried up).
The Diskoisland metal supposedly formed when molten basalt
hit coal seams. The reaction was like smelting - iron oxide in the
basalt magma reacted with the coal, and produced iron metal. That
doesn't seem to work for the Putorana stuff, as the basalt is too rich
in iron -- if iron had been smelted out of it, the basalt would be poor
in iron.
My current guess is that the iron metal came from iron sulfide
liquid. There's a lot of iron sulfide ore in the Putorana/Noril'sk area,
so having sulfide is not a problem. Perhaps the sulfide could get
"roasted" naturally, and drive the sulfur off into the air. The iron would
be left behind as metal. Just an idea. Perhaps our Russian friends
know more about Putorana??
Cheers!
Allan
Allan H. Treiman
Lunar and Planetary Institute
3600 Bay Area Boulevard
Houston TX 77058-1113
281-486-2117
281-486-2162 FAX
[EMAIL PROTECTED]
-----Original Message-----
From: Dave Harris [mailto:[EMAIL PROTECTED]]
Sent: Saturday, February 23, 2002 3:17 AM
To: metlist
Subject: [meteorite-list] puzzling Putorana
Hi there,
I have just read Mr. Norton's article in this quarter's Meteorite magazine
on Putorana where he speculated that the iron in the basalt was derived from
mantle plumes conducting iron from the core to the magma chambers in the
lithosphere - I was just wondering how actually plausible that mechanism
actually was.
I thought that a more likely scenario for the creation of Putorana iron may
have been the effect of a magmatic plume coming into contact with a highly
carbonaceous sedimentary deposit and the iron compounds are then reduced to
native iron (much in the same way that commercial iron is produced by
reacting with coke). I accept that the sedimentary deposits would have to
be subducted to quite some depths before the appropriate temperature and
pressures arose, but it still seems more likely a scenario to me than a
outer liquid core streamer of iron travelling a couple of thousand
kilometres upwards, against gravity and still keeping the iron in a liquid
enough state to mix with magma.
Any ideas? I wonder if there is any overriding chemical evidence that the
iron is sourced from the core rather than liberated as part of a reduction
of mantle silicates and oxides (possibly the presence of Ni in the iron is
the evidence that supports the core theory - I dunno!)
Don't laugh at me if I have written a load of rubbish here! I need to learn
and only by thinking about this stuff and making gaffs will I learn
anything - some of you people out there know more about Geology than I will
EVER learn, so I bow to your undeniably profound knowledge!!!
Ideas/opinions please!
--
In gentle decay,
dave
IMCA #0092
[EMAIL PROTECTED] (for IMCA member contact)
http://www.meteorites.ic24.net/index.html
http://www.meteoritecollectors.org
"I have a proof that x^n+y^n=z^n never has integer solutions for n>2.
However, it won't fit into my signature file...."
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