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Re: fossil meteorite
Matt Morgan schrieb:
> Bernd Pauli wrote:
> > Sicree et al. also report that "more than one dozen Ordovician
> > 'paleochondrites' have been recovered from limestone quarries at
> > Brunflo and Österplana, Sweden".
> > They are thoroughly altered and most of their material has been
> > replaced by barite and calcite.
> > [Ref.: Thorslund P. et al. (1981) NATURE 289, pp. 285-286 and
> > Nyström J.O. et al. (1989) NATURE 336, pp. 572-574].
> How does he know it is a meteorite then? Severely altered to me, means
> it doesn't retain its orginal "meteoritic" characteristics. Please
> explain if possible. Thanks! - Matt Morgan (Mile High Meteorites)
Hello Matt, hello List,
With regard to Brunflo, the Big Blue Book says: ‘Chondrule structures
were recognized in a block of Ordovician limestone (approx. age 450
my.). The silicate minerals have been replaced by calcite, barite and a
Cr-V-'phengite'. The only original mineral preserved is chromite, the
composition of which suggests an H-group classification, P. Thorslund
and F.E. Wickman, Nature, 1981, 289, p.285, P. Thorslund et al., Lithos,
1984, 17, p.87.’
The key words are:
C h o n d r u l e s t r u c t u r e s were r e c o g n i z e d.
The limestone inclusion was identified as a highly metamorphic (=
exhibiting structural change) Mg-Fe-silicate-rich material. It still
showed the imprints (proper word?) of porphyritic, barred and radial
chondrules (on a microstructure scale) much like you can still find the
footprints of dinosaurs (or even humans on formerly volcanic soil =>
ash) but no trace of the creatures themselves.
Best wishes, Bernd
P.S.: Matt what became of the L'Aigle specimen you offered? - it is no
longer to be found in your sales list.
References: