[meteorite-list] Gao, Gao & Gao

From: star-bits at tx.rr.com <star-bits_at_meteoritecentral.com>
Date: Fri, 16 Mar 2007 9:01:46 -0800
Message-ID: <15239258.1174064506301.JavaMail.root_at_web15>

Zelimir Gabelica <Zelimir.Gabelica at uha.fr> wrote:

<1) Gao(b) that is a CR (S1), found by Eric Twelker in a parcel full of
"normal Gaos" sent to him from Burkina Faso.>

    I also found one of these stones in a shipment from Burkina Faso. According to my source it came from a small village named Pro which is near Gao. I provided a piece to ASU for classification but before they got around to doing anything with it I found out Eric Twelker had submitted elsewhere for classification and ASU never finished the classification. I provided this information to Eric T. but it didn't make it into the bulletin. Out of 198 grams I had after cutting I kept a 36 gram endcut, sold 4 grams and the rest went to various research institutions.

<2) The Gao-melt (H imb) described and put for sale by Eric Olson. This
stuff is definitely far different from Gao (H5) in that, when cut, this
almost black meteorite shows "melts and rivers" just as Portales or others.
Definitely a weird stuff........E. Olson is anouncing on his site since a time that these are "under
study". Did someone got more recent news ?

     I don't know if there was ever an official paper on the melt although one was supposedly in the works. I was however told that it is Gao-Guenie. In addition to the one large stone, which I cut, I have an 88 gram piece that I have left uncut and have found a half dozen small (5-15 gram) pieces. In addition I know Mike Farmer had a large stone which he cut in half and sold on eBay. All of these pieces had one thing in common, rivers of melt and black shocked unmelted areas and "NO" normal Gao associated with them. Hard to believe that they were the same fall. However I have since found a couple other stones which do show normal and melted Gao together. See the following photos.

    Half and Half stone weight 10.68 grams. The other half was given to the U of AZ for their studies.

<http://star-bits.com/collection/gao-halfmelt.JPG>

    Broken oriented stone 29.08 grams with 3mm wide black glassy silicate vein.
 
<http://star-bits.com/collection/gao-vein.JPG>

    I accept that the melt is Gao-Guenie, but they are very different animals.

<Once cut, not only they showed the strange metled parts but also huge vugs, some of which reaching
20+ mm !!>

    My large stone had a 1cm x 1cm hershey's kiss shaped vug which by great skill (luck) I cut perfectly parallel to the bottom. The three slices, bottom, top, and middle (hole) went to the ASU collection. I'd post photos, but I never took any and never got back to ASU with a camera to remedy that error.

<Note: my source confirmed that Gao imb and Gao (H5) are (still being) found
on the unique strewnfield. >

    I have not been offered any Gao in several years, but I know others who have bought recently. I don't know if it includes any of the imb.

Martin Altman wrote:

<Hehe, I have also a Gao(c) oder (d) or (e),
in a batch of dusty Gaos from Carion, there was one, which turned out after
cutting not to be a Gao, but a different ordinary chondrite, rather an L
than a H. Unfortunately it had only 10g, so it still lays around here unclassified. >

     I also found a small stone that when cut looked like an "L" chondrite. After cutting the 2 pieces weighed 4 grams total. I figured more would show up and when a nice sized piece showed up I'd get it classified, but I have yet to find another piece.

--
Eric Olson
7682 Firethorn Dr
Fayetteville, NC 28311
http://www.star-bits.com
 

Received on Fri 16 Mar 2007 01:01:46 PM PDT