[meteorite-list] THE OLDEST METEORITE ?

[Don Merchant]

Hi Shawn and List. Interesting you brought this up. I remember years ago 
purchasing a rare meteorite specifically because of its age. Could not 
remember for which one (old age thing!) anyways I remember what meteorite 
that was.....Tieschitz. Fell July 15, 1878 at 1345 hrs. I will try and find 
the article/study/results which I know I saved on this meteorite and forward 
it to the list...Since I have it in my collection I wrote a few things about 
the meteorite on my index card file. Contains pre-solar Al rich oxide 
grains. Most of these grains originate in red giants. Age was estimated at 
4.59 A±  0.09Ga which exceeds the age of Allende and the others mentioned. 
At least this is what I had jotted down.
Sincerely
Don Merchant
IMCA #0960
----- Original Message ----- 
From: "Shawn Alan" <photophlow at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Thursday, January 28, 2010 7:04 PM
Subject: [meteorite-list] THE OLDEST METEORITE ?


> The age old question, which meteorite is the oldest? I have done some 
> reading on this topic and asked a few people what they thought and here is 
> what I have gathered so far.
>
> Allende is 4,565.45 (+-0.45) m.y. and I have also seen Allende dated at 
> 4,5685 b.y. Burkhardt (2007), which could make Allende one of the oldest 
> meteorites. But then I have read that D'Orbigny, stated by Qing-Zhu Yin 
> (2009) is the oldest meteorite, with an age of 4,567.91 (+- 0.76) m.y. But 
> to counter Qing-Zhu Yin claim, in 2009 Tistarite a new refractory mineral 
> was found in Allende which this new refractory mineral is among the first 
> solids formed in the solar system ( American Mineralogist 2009 ).
>
> If this didn’t get confusing enough, a newly identified refractory 
> inclusion in Murchison composed of hibonite represents some of the 
> earliest condensed solids or residues from the early, hot, solar nebula 
> (Liu et al., 2009). These refractory inclusions comprise of platy crystals 
> and blue aggregates, which formation occurred hundreds of thousands of 
> years before the formation of CV CAIs ( http://www.meteoritestudies.com/ )
>
> But some people have a different idea of the age old question and feel 
> that the Vigarano meteorite is the oldest meteorite. Vigarano fell at 9:30 
> pm 22 January 1910 in Emilia, Italy. Two stones of 11.5 kg and 4.5 kg were 
> found. This is the type specimen for the CV class. A case can be made for 
> Vigarano being the oldest meteorite. Although older ages have been 
> recorded for other meteorites they are isolated measurements and do not 
> give as consistently an old age as does Vigarano ( 
> http://www.star-bits.com/VIGARANO.htm ) .
>
> Now back to the question what is the oldest meteorite?
>
> Shawn Alan
>
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