Hello Jeff, Matthias, Ted, all,
Your wise suggestions about the blue inclusion are highly appreciated.
I also first thought of hibonite that was mentioned in a similar
discussion we had on the list a couple of years ago. At the time, Jeff
Kuyken showed us a chondrule-like inclusion in Isheyevo and hibonite
was one of the hypotheses retained . I don't really remember the
detailed discussion that resulted but this info is now probably hidden
somewhere in the archives .
By luck, this debate (with hibonite hypothesis) as well as the
inclusion pics are still available on Jeff's site (Jeff K, I hope you
don't mind if I provide the link):
http://www.meteorites.com.au/features/isheyevo.html
The blue color in Isheyevo (as it is in Allende shown by Ted), is more
intense than the light blue shade of our TNZ "chondrule" so I did not
retain at first that hypotheis. (also because all the terrestrial
hibonites I have seen are dark brown but more often just black; the
best crystals so far come from Madagascar and I have in my mineral
collection a 6x4x3 cm single cristal, just full black- from the famous
Betroka deposit).
I now realize the hibonite hypothesis is very likely.
But enstatite is another possibility indeed. I have a terrestrial
enstatite sample that is blue-green. The synthetic enstatites we once
had synthesized in the lab are logically white.
Two last questions (sorry for insisting):
1) Should we consider this just as a curiosity or does someone believe
this could have some pertinent significance in the case of a CM2
chondrite ?
2) How can we make sure the "round light blue circle" shown here is a
chondrule or a CAI ? Jeff firmly states that the TNZ hibonite is
embedded in a CAI and Ted shows the same in Allende. Would that imply
the TNZ "circle" is also a CAI rather than a chondrule, despite of its
quasi perferctly round shape ?
My best wishes,
Zelimir
Ted Bunch <tbe...@cableone.net> a écrit :
Dear Zelimir- Jeff beat me on the response.
Attached is a true hibonite in an Allende CAI. Your blue object could be a
lighter blue hibonite or an enstatite chondrule that, on occasion, has a
blue hue depending on the light source, angle of illumination, light
scattering, etc.
Ted
On 2/6/10 10:06 AM, "zelimir.gabel...@uha.fr" <zelimir.gabel...@uha.fr>
wrote:
Hi List,
Here are 3 pics of a genuine blue chondrule spotted upon breaking a
fagment of the CM2 meteorite Tanezrouft 082 (purchased last June in
Ensisheim, from A. Gouesslain/J.-L. Parodi, the meteorite finders).
See here:
http://www.agab.be/question/question.html
Question: what could be the origin of such a strange turquois-like
blue color ?
Could it be due to some traces of Cu2+ salts neutralizing some
refractory silicates ? (despite tha fact that the presence of Cu was
apparently not reported in the meteorite analysis, see the Met. Bull.
writeup added in the URL).
Or could that just be (sometimes) the natural color of some
(ortho)pyroxenes ?
Or olivine ?
However, I don't remember having ever seen any olivine showing such a
"true" blue color. Shouldn't olivine (always?) rather be
"olive-green", whatever its origin (terrestrial or asteroidal) ?
Thanks for sharing your thoughts or expertise.
My best,
Zelimir
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