[meteorite-list] survivability of a meteorite?

From: P. Gessler <cetuspa_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:33 2004
Message-ID: <3B591B05.3DAD0D06_at_home.com>

Ed Majden wrote:

"Land height has nothing what ever to do with the survivability of a
meteorite."

Land height has EVERYTHING to do with the survivability of a meteorite!
Perhaps you meant meteoroid?

Meteoritics and Planetary Science Vol. 36 Number 6.
Meteorite stranding surfaces and the Greenland icesheet

one of the main features of meteorite producing icesheets in Antarctica
is a unique natural concentration and preservation mechanism
characterized by dry patches of snow free ice at high altitude.

"Meteorites are only found on a minor proportion of the exposed blue ice
of Antarctica; and by association, only regions that duplicate many or
all of the conditions specific to established surfaces can be expected
to harbor meteorites in Greenland. We consider four requisite criteria
in our search for sites which mimic the characteristics of Antarctic
meteorite stranding surfaces:
1) obstructions to ice flow, visible or otherwise indicated
2)exposed blue ice in an accumulation zone
3)ALTITUDE as a proxy for climatic conditions
4)persistence of conditions"

"Such sites must meet the criteria previously discussed regarding
altitude, obstructions and persistence of conditions before they can be
considered excellent candidates for meteorite stranding surfaces."

"Antarctic meteorite stranding surfaces are typically found at altitudes
above 1500m"

"the icesheet margin terminates at altitudes of 1000m or lower, where
melting and sublimation remove more ice than inflow delivers."

"On several occasions, ANSMET has searched ice fields at altitudes lower
than 1500m, but very few specimens have been found." "This observation
has been repeated to differing degrees in several localities, suggesting
that altitude serves as a helpful proxy for the cold, dry conditions
that support meteorite stranding surface processes."

Paul Gessler
Received on Sat 21 Jul 2001 02:02:47 AM PDT