Re: [meteorite-list] ¿ ventifacted ?

[Nicholas Gessler]

Hi,

Yes, "wind faceted" (wind and sand ablation) seems to be the key feature of 
relevance.  If you look at photos of the alleged meteorite found on Mars, 
it contains quite a few facets.  And the ridges between the facets are very 
sharp.  I have seen hard quartzite and flint-like rocks on deserts with the 
same sharply delineated features.  The ventifacted chondrites, on the other 
hand, do not show these facets or sharp delineations.  Neither does the 
banded iron example or the other iron meteorite from Antarctica.

As far as I know, these sharply delineated facets occur with wind and sand 
from a constant direction over a long period of time.  And the material has 
to be hard and homogeneous.  Consequently I wonder what a terrestrial iron 
meteorite would look like subjected to the same conditions?  I have a new 
NWA iron that is otherwise round and smooth but clearly shows those lines 
but no facets.  I'm sure it was attacked by water and by wind and sand, but 
how much by each I just don't know.  I suppose even a solid hunk of 
non-meteoric iron subjected to the same conditions would answer the 
question.  Unless the rock found on Mars is an ataxite, I would also expect 
that any attack (whether by acid or wind and sand) would reveal some 
evidence of Widmanstatten lines.  I don't see any evidence of that in the 
Martian photograph.

So as much as I think it's a keen idea to find a meteorite on Mars, I'm not 
convinced.  "Extraordinary claims require extraordinary evidence."  So my 
questions are:
a)	Why does the Martian rock show faceting?  Does that support or detract 
from the claim that it is an iron meteorite?
b)	Exactly what analysis was done on Mars?  I have only seen the most 
general reports for PR purposes.  Can anyone point me to a more definitive 
report?  Do we have access to the thermal heating and dissipation data, for 
instance?  And what else?

Cheers,
Nick