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Re: Great Siberian Explosion

Lawrence and Rebecca Linteau wrote:

> Dear Bernd,
>
> Your explanation stated that, "a comet could not pass through the
> lower atmosphere." What about Murchison? Cometary or no?
> Respectfully, Lawrence Linteau.

Hello Rebecca and Lawrence, hello List!

As the Linteaus' question may be of general interest to other list
members as well, I am sending my answer to all of us.

In accordance with several scientific papers, I'd conclude that
Murchison isn't of cometary origin.

1) T.H. Burbine et al. (1995) Could G asteroids be the parent bodies of
the CM chondrites? (abs. Meteoritics 30-5, 1995, p.494, excerpts):

"Both  F o r t u n a  and  E g e r i a  have an absorption feature ...
that is similar ... to those found in many CM chondrites. The visible
and near-infrared spectra of Fortuna closely match the spectra of CM
chondrites  M u r c h i s o n  and LEW 90500".

"Fortuna and Egeria appear to be two of the best spectral matches for
the CM chondrites".

2) CALVIN W.M. et al. (1997) Spectral characteristics of iron-bearing
phyllosilicates: Comparison to Orgueil (CI 1), Murchison and Murray
(CM2) (Meteoritics 32-5, 1997, pp. 693-701, excerpts):

"A genetic relationship between carbonaceous chondrite meteorites and
certain dark asteroid classes (C, G, F, B) is commonly assumed ..."

3) T.H. BURBINE (1998) Could G-class asteroids be the parent bodies of
the CM chondrites? (Meteoritics 33-2, 1998, pp. 53-258, excerpts):

"Three G asteroids have been identified through previous theoretical
studies as being likely meteorite source bodies due to their locations
near resonances. Two of these objects, 19 Fortuna and 13 Egeria, have
spectral properties that are consistent with such a linkage with CM
chondrites".

"The visible and near-infrared spectrum of Fortuna matches very well the
spectra of CM chondrite Murchison (bulk powder) ... Burbine (1991) has
noted that 19 Fortuna and the bulk powder spectrum of  M u r c h i s o
n  have one of the best spectral matches between asteroids with 52-color
data ... and meteorites from Gaffey (1976)".

Best wishes,

Bernd


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