[meteorite-list] Recovered masses and survival

From: Kelly Webb <kelly_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:11 2004
Message-ID: <3A933E0E.BDF607CA_at_bhil.com>

Hi, All,

Here's the breakdown between falls and finds by class
of historic meteorites (non-antarctic, all pre-1985):

   TYPE FINDS FALLS
========== ======= =======
Chondrites: 51.3% 87.8%
Achondrites: 1.0% 7.9%
Mesosiderites: 1.6% 0.8%
Palasites: 3.8% 0.3%
Hexahedrites: 12.0% 1.0%
Octahedrites: 29.0% 2.1%
Ataxites: 1.1% 0.1%

One can compare the disparity of representation in finds
(irons persist better and are easier to find, etc.) by
comparing finds to the actual rate represented in falls by
calculating the RECOVERY RATIO:

  TYPE RECOVERY RATIO
============= ==============
Octahedrites: 1381%
Palasites: 1267%
Hexahedrites: 1200%
Ataxites: 1100%
Mesosiderites: 200%
Chondrites: 58.43%
Achondrites: 12.67%

Some obvious selection effects show up. Nearly half of
the chondrites are lost. Only one meteorite in 1000
is an ataxite as compared to 79 achondrites per 1000,
but they are found in almost equal numbers. The most
glaring fact we see in the recovery ratios is the
tremendous loss of achondrites: only one in eight is recovered; 87.33%
of them are lost. This suggests, for example, that there are lots more
SNC's, Eucrites, Diogenites, Howardites, Aubrites, and Lunars still out
there! Presumably, once the fresh fusion crust degrades
sufficiently, they become unrecognized, unremarked, and
uncollected.

There's a sad thought.


Kelly Webb

"E.P. Grondine" wrote:

> Hi all -
>
> Perhaps some estimates could be made for survival
> through entry and ground survival, these estimates
> applied to the recovered totals, and parent population
> estimated. But the breakdown would have to be more
> refined than stony, iron, and stony-iron.
>
> EP
>
Received on Tue 20 Feb 2001 11:03:26 PM PST