[meteorite-list] searching for the correct terminology

[Randy Korotev]

For meteorites exposed a long time in deserts, one of the processes 
is ablation or abrasion by the wind - sand-blasting.  Omanian lunars 
seldom have fusion crusts.  Look at the Dhofars 461 and 465 here:

http://meteorites.wustl.edu/lunar/stones/dhofar0026.htm

If you handed those rocks to a geologist, she'd say, on the basis of 
the 3-sided shapes, "those are ventifacts," not, "those are 
meteorites."  Omanian meteorites have been getting smaller with time!

http://en.wikipedia.org/wiki/Ventifact

Scientists who've studied the Dar al Gani field in Libya say that one 
of the reasons for the preservation is that the wind-blown sand is 
from carbonate rock (soft), not quartz (hard).  The meteorites in the 
Dhofar photos above appear to be sitting on carbonate desert 
pavements, but I have to conclude that there's a source of quartz 
sand somewhere.

Even in Antarctica, meteorite fusion crust is lost to wind ablation, 
even though there's little sand in the wind.  All meteorite 
collection places in Antarctica are places where the katabatic winds 
are blowing so hard that snow does not accumulate and the ice is 
being ablated by the wind at the rate of a few inches per year.



At 12:04 2009-09-11 Friday, you wrote:
>You will probably think I am a bit off the latch with this question
>but here goes anyway... In the world of meteorite terminology, is
>there a term or word which describes the loss of fusion crust (by
>forces of nature) from stony meteorites.  'Spalling' possibly?  The
>loss of crust, part or all, seems to be a rather common occurrence
>especially for some of the more friable stonys.  With the crust gone,
>the stone is 'denuded'?
>
>Mike in CO

Randy Korotev
Saint Louis, MO
korotev at wustl.edu