Bjorn, List,
I never meant to imply that it was a "raw" piece
of bog iron. Clearly it has been through the
furnace. Bog iron occurs naturally in many,
much smaller, irregular pieces.
The traditional "furnace" was a stone cylinder
lined with clay, with fuel on the bottom, whose
combustion was assisted by a bellows. Pieces of
iron -- bog iron, Grandpa's broken belt buckle,
a pan with a hole in the bottom -- were tossed
in the top, as was more fuel when needed, usually
charcoal.
Temperatures ranged from 300 C at the top
and reached up to 1200 C or more at the bottom.
The slag, oxides of iron, silicon, etc., drained out
through a port at the bottom of the furnace.
It was a highly reducing environment with lots
of carbon monoxide which would combine with
the oxides (impurities) and leave the iron in an
elemental state... more or less.
The result was a spongy vesicular low-density
blob of low-carbon iron called a "bloom." That's
what the famous Hatlestrand meteorite is. Of
course, after that you have to heat it and pound
it and increase its density, eliminating voids,
and so forth. (List members commented on the
apparent low density; it lifted too easily!)
Unless you eliminate the carbon content, the iron
won't be malleable and can't be worked. I would
guess that whoever made this bloom didn't know
what they were doing -- it is far too large a bloom
to be worked on an anvil by a mere mortal. It would
need a jötunn or Thor himself to hammer it flat...
This type of refining is immensely difficult work
and is only utilized in historical times when iron
was costly and precious, i.e., anciently. To recognize
it requires, not a geologist, but a metallurgical
archeologist. Bog iron is, of course, merely one
type of iron ore, albeit a low grade form.
Selbekk (a geologist, not a metallurgist) said
"The Hatlestrand stone [is] a lump of slag after
attempts to extract iron from iron ore by means
of heat. And as far as I've heard, it went on, the
burning of iron ore in the area on Hatlestrand
in earlier times, he says." Yes, it was bog iron.
Selbekk should know that Norway (unlike
Sweden, curse their Volvos) lacks commercial
varieties of iron ore except in its very far North --
very far, like Kirkenes on the Russian border near
the popular vacation spot of Murmansk! In fact,
this year Norway will be supplying its Arctic iron
ore to the hungry steel mills of China by way of
the Arctic Ocean route for the first time:
http://www.treehugger.com/files/2010/09/norway-ship-iron-ore-across-arctic-to-china.php
and
http://www.nordicbulkcarriers.com/media/?sub=3
I suspect that the Hatlestrand bloom was somebody's
attempt to make iron the "old-fashioned" way, a failed
attempt. At any rate, it didn't result in a meteorite or
anything that even vaguely resembled one. It doesn't
make Knut Jørgen Ødegaard seem very authoritative.
Sterling K. Webb
----------------------------------------------------------------------
----- Original Message -----
From: "Bjorn Sorheim" <astro...@online.no>
To: <meteorite-list@meteoritecentral.com>
Cc: <astro...@online.no>
Sent: Friday, October 15, 2010 5:38 PM
Subject: [meteorite-list] The 'Ødegaard 54kg meteorite': Iron slag says
NHM, Norway
Sterling, List
The geologist says it is rather iron slag from
trying to make iron from iron ore, not bog iron.
To me the stone may look like something like
a local plutonic rock from one of the images.
It is a great astonishment to learn that it
has only a volume of 9 litres, still it looks
like it is ~40cm in length. Try to calculate that...
But the depressing thing and main point about the
story is that you have an astronomer, who have
very little or no deeper knowledge about rocks and
-meteorwrongs- specifically. And in the last ten
years he have made the whole norwegian press,
+ radio/tv (he was on national TV with this) believe
he is an expert in meteorites.
He is an absolute beginner, especially compared to
most on this list. I am not even shure he has begun learning
about meteorites, cause what he says about stones
supposed to be meteorites never make sense. It looks like
he has no interest in them. It's being in the news with a
sensational story that matters to him, I'm sorry to say...
Bjørn Sørheim
Bjørn Sørheim
-----------------------------------------------------------------------------------------
Bjorn, List,
As I posted, it was an obvious piece of bog iron, with all the
characteristics. Bog iron was still "refined" by progressive
melts up into the 18th century until cheap modern iron
and then steel became available.
This was true everywhere that it could be found. There
was a flourishing bog iron industry in Colonial America,
and I have no doubt it was still being done on homesteads
in Norway through the same time period, which is why
the metallurgist said it was 2-3 centuries old or more.
I imagine he recognized it as incompletely refined bog
iron.
Such a meteor-wrong could be as easily found in New
Jersey or New England as in Norway or Denmark. It is
common find (in smaller, unrefined pieces) anywhere
with well-watered acidic swampy meadows. It is created
by "iron-excreting" bacteria!
Sterling K. Webb
--------------------------------------------------------------------------------
----- Original Message -----
From: "Bjorn Sorheim"
<<http://six.pairlist.net/mailman/listinfo/meteorite-list>astrogeo at
online.no>
To:
<<http://six.pairlist.net/mailman/listinfo/meteorite-list>meteorite-list
at
meteoritecentral.com>
Cc: <<http://six.pairlist.net/mailman/listinfo/meteorite-list>astrogeo
at
online.no>
Sent: Friday, October 15, 2010 4:00 PM
Subject: The 'Ødegaard 54kg meteorite': Iron slag says NHM, Norway
Supposed to be Norway's 2nd largest meteorite, was just
old iron slag.
KJR Ødegaard was 99% certain it was a meteorite. Would
eat 'grey stones' if it was not!
I might recommend him staying with his heavy stars in the future.
At least norwegian press should stop using 'meteorite expert' about
him and his rock evaluations.
Translate using translate.google.com
www.kvinnheringen.no/nyhende/article5346528.ece
www.bt.no/nyheter/lokalt/Meteoritt-var-ikke-fra-himmelen-1174890.html
Bjørn Sørheim
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