[meteorite-list] What are the FeO/MnO Ratios for the Kalahari 008, 009?

From: Norbert Classen <trifid_at_meteoritecentral.com>
Date: Wed Aug 10 11:22:06 2005
Message-ID: <200508101522.j7AFMh4U013739_at_ev1.craft.de>

Hi Adam, Martin, Jeff, and All,

First, as for Martin's question - it's not that unusual that two different
sized individuals of one and the same fall land that close to each other.
Take for example the 8 kilo + main mass of the SaU shergottite strewnfield
(SaU 008). Other, much smaller stones (SaU 051, and other stones comprised
under the original SaU 008 designation) were recovered from the vicinity of
the main mass. I could quote other examples, such as the Dhofar 302/908
strewnfield, where very small individual masses (not fragments) and larger
stones were found within the distance of less than 100 meters. This
certainly depends on the original impact angle of the fall, and it doesn't
sound that unusual to me.

As for the CRE and terrestrial ages of Kalahari 008, and 009, you have to
read Kuni Nishiizumi's study with utmost care. He isn't saying that the
terrestrial age is several hundred of thousand years - he's just confronting
us with two possible scenarios that might explain the cosmogenic nuclide
values within these rocks. The first scenario proposes a long terrestrial
residence time at the find site (that also would be valid for a terrestrial
rock subjected to the same conditions!!!), and the second - more probable
scenario - proposes a very short transition time, and the implantation of
these radionuclides in space. So don't mistake the first scenario for a
calculation of a terrestrial age for the Kalahari lunaites. As far as I
know, short transition times, i.e. CRE ages, make it more or less impossible
to determine a terrestrial age (at least via the usual C14 analysis). A
terrestrial age hasn't been determined for Kalahari 008, and 009, and thus
there might be no contradiction at all between the W1 classification, and
the other given data.

Last but not least, I agree with Jeff Grossmann's notion that the find story
is odd. Unconfirmed rumors have it that these lunaites were either found in
South Africa or in the neighboring Namibia (both countries with strict
meteorite laws), and that the "find location" in Botswana was just made up
for obvious reasons. However, these rumors aren't consistent with the fact
that the finder obviously isn't interested in selling any of his stuff - it
wouldn't make much sense to make up anything in this case... Anyway, the
story is strange, and it sounds improbable that a person who's not into
meteorites at all recovers a large lunaite, AND - having no idea of what he
has there - combs the place for additional fragments. That's really odd.

Lunatically yours,
Norbert

-----Urspr?ngliche Nachricht-----

Hi Adam,

I don't know strewnfield stats so well,
but for the case, that they aren't fragments of the same stone, which were
transported later by a mechanism, the heck I dunno which,
wouldn't it be highly improbable, that two stones of a fall landed so close
to each other, especially as they have such different sizes?

???
Martin

----- Original Message -----
From: "Adam Hupe" <raremeteorites_at_comcast.net>
To: <meteorite-list_at_meteoritecentral.com>
Sent: Wednesday, August 10, 2005 8:31 AM
Subject: Re: [meteorite-list] What are the FeO/MnO Ratios for the Kalahari
008,009?


> Dear List,
>
> An update, it looks like even though the two Kalahari lunar meteorites
have
> completely different classifications they are paired. This makes sense
> since they were found just 50 meters apart. The abstract below proves
this
> since they both share the same CRE and terrestrial ages:
>
> http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5270.pdf
>
> Kind Regards,
>
> ------------------------------------
> Adam Hupe
> The Hupe Collection
> Team LunarRock
> IMCA 2185
> raremeteorites_at_comcast.net
Received on Wed 10 Aug 2005 11:21:11 AM PDT