[meteorite-list] Regmaglypts

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Wed, 27 Jan 2010 10:52:17 -0800
Message-ID: <93aaac891001271052k392065b2o79a0439f4b75babf_at_mail.gmail.com>

Hello Again Phyllis, All,

> 1. ?My reference to ?bubbles? is to morphology, NOT voids. ?Another meteoritic example of ?bubble morphology effects? is pallasitic olivines such as Springwater and Imilac.

So you're saying that the bubbles on the surface of your irons are
like the olivine crystals in pallasites? And yet they don't occur
within the meteorites -- just on the surface.
There are a few problems with your reasoning.
1) The reason that pallasites look the way they do is because of the
fact that they're full of circular inclusions (peridot) that weather
out more quickly than the iron. Those inclusions aren't just on the
surface - they occur throughout the meteorite, so when you compare
surface morphologies, you can't really equate the two unless you're
saying that irons are full of vugs. If you acknowledge the fact that
iron meteorites are, on the whole, not full of, well, holes, then
you're comparing apples to oranges.
2) Pallasites such as Springwater and Imilac are heavily weathered
pallasites. In fact, most pallasites are quite weathered. I haven't
been able to find any nice photos of the outer surface of a fresh one,
but if you're going to compare fresh irons to weathered pallasites,
well, again, you're comparing things in such a way as to make a
comparison between two changing variables - in this case, initial
outer surface formation - and weathering effects.

This just isn't good logic or a particularly scientific way of thinking.

> A thought experiment: Once again, envision a melt mass of olivine and nickel-iron solidifying under microgravity conditions ? surface energy dominates gravity.
> On cooling, olivine begins to solidify before nickel-iron. However, since olivine and iron-nickel share a range of temperatures where both are still at least partially liquid (mushy stage), as cooling continues, still-plastic olivines can be surrounded by and sometimes infiltrated and pushed apart by liquid nickel-iron.

Sure...

> Cut and polished sections of Springwater and Imilac reveal this as a relatively complex process. ?Observe 120 angles between some olivines, evidence of a system governed by surface energy.

We could be looking at remnants of convection currents, impact-induced
deformation...anything, really. "Surface energy" is far
too-simplistic a way to think about things.

>Some olivine boundaries are straight (interior polyhedral shapes); some are circular (a sphere minimizes surface area to volume ratio); some straight and curved (perhaps on the outer surface of the olivine mass). See my "Stepping Back in Time" article in Meteorite magazine Nov. 2003, Vol. 9 No. 4, pp. 21-22 or see it in the publications list on my website at http://meteormetals.com

But this says nothing to support your point; these could have formed
in any number of situations in a fairly static (rounded crystals, eg
Springwater) or turbulent (larger, broken crystals, eg Imilac)
environment.

> 2. ?There is NO WAY that the thermal history of a metal can be calculated in reverse, despite hundreds of papers in the meteoritics literature since the original paper of Osmond and Cartaud in 1904 and the more recent, detailed papers on ?metallographic cooling rates!? ?That is more than 100 years of circular reasoning! ?Industrial metallurgists would be a lot happier if this backward calculation were possible. ?It is NOT!

You're right and the past century of science is wrong. Forgive me for
saying this, but you sound precisely like a DeRusse, etc. There's a
reason science has been done the way it has, and, yes, the thermal
history of metal can be deduced based on observed crystalline
structures, etc. - to an extent. Once things get completely remelted,
yes, the history becomes destroyed, but while some mineral structure
remains, there are always traces.
Take, for example, Zacatecas (1969)

http://tin.er.usgs.gov/meteor/get_original_photo.php?recno=5632419

That photo pretty much debunks everything you just said about not
being able to determine thermal histories. You can clearly see the
original widmanstatten pattern, and the newer recrystallization
pattern superimposed upon it.
Based on the level of recrystallization, we've been able to determine
roughly the degree to which it was heated, etc.
If you don't believe me, I really don't know what to say; it's accepted science.

You're standing alone saying that all of science in this area is
wrong, and your reasoning so far has gone in the face of accepted
asteroidal formation theories, accepted physics regarding atmospheric
entry, and, to be frank, it makes little sense given the external and
internal morphology of meteorites...and you've got nothing to back
your theory up.

> 3. ?Speaking of industrial metallurgists, do another experiment: show a cut section of any nickel-iron or stony iron meteorite to a modern INDUSTRIAL metallurgist. ?Ask him or her to describe the microstructure, without you giving them any ?meteorite words? or concepts. ?Then, Listen! ?Next, give that person one of the metallic meteorite papers in the meteoritics literature (other than mine) and see if that person can even understand the language and concepts. ?Meteoritics metallurgy has sealed itself inside an old language, not accessible to today?s busy, industrial metallurgists. ?To quote one of my industrial metallurgist friends who is a casting expert and who has become a meteorite collector, "meteorite metallurgy is in the Stone Age."

I don't know about that - Buchwald was a pioneer in the field of
metallurgy, and wasn't even that interested in meteorites, from what
I've gathered. Well, that's not to say that he wasn't interested in
them, but I believe that he considered himself more of a metallurgist
than a meteoriticist.
But that said, the folks who understand the structural nuances of iron
meteorites are dealing with a completely different science and
completely different processes than your average industrial
metallurgist. You might as well show a marine biologist at Sea World
a scientific paper on some prehistoric aquatic animal and expect them
to make sense of it. Yes, it's kind of in the field of their study,
but you're looking at very different parts of each discipline.

But I'm still left wondering how you explain shower of complete iron
meteorites such as, well, namely Sikhote-Alin.
In this fall alone, there are thousands of smaller "complete"
meteorites that are covered in regmaglypts. If each of these cooled
independently, as you say, with bubbles on each and every surface, the
way you would explain this is with a veritable swarm of thousands of
bodies entering the atmosphere from the start, no?

...Again, sounding ridiculous.

Jason

> We need a NEW METALLURGY for meteorites! ?Imagine what we could learn!
>
> Phyllis Budka
> http://meteormetals.com/
>
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Received on Wed 27 Jan 2010 01:52:17 PM PST