[meteorite-list] Ash Creek (West) "Silvery-Blue Marks" Revisited

From: meteoritefinder at yahoo.com <meteoritefinder_at_meteoritecentral.com>
Date: Tue, 28 Apr 2009 22:23:36 -0700 (PDT)
Message-ID: <233449.58734.qm_at_web39602.mail.mud.yahoo.com>

Hello All,

? You might recall the meteorite that I had mentioned before that had the very prominent "silvery-blue markings".?Michael Johnson was kind enough to host the photo here:

???http://www.rocksfromspace.org/West-markings.html


???At the time, I proposed that it might perhaps be a "melt spray" from some type of inclusion in the stone. That does seem to be the predominant opinion according to postings from those that have chimed in with their thoughts (thanks to all of you!). Another thought offered by a researcher, who was going on nothing more than my description and did not have the benefit of seeing the specimen in person, was that it might simply be areas where the original fusion crust was somehow "scratched" off, perhaps upon landing. I think I can now put this latter theory to rest.? It is definitely NOT due to "scratched off" fusion crust.

? A cancer surgeon friend of mine here in Little Rock has a very nice compound microscope at his home that he uses to examine archaeological artifacts ( a hobby that I share with him as well). I finally got around to visiting him tonight, and he graciously allowed me to use his scope to view these markings. With the admitted assurance that I am no expert in this, I still think I can say with 100% accuracy that the marks are DEFINITELY some type of melt spray. Under magnification, the marks look almost like paint that has run or been blown across the surface of the meteorite. There are countless "craters" or vesicles that are filled with the colored material. Then there are areas at the end of some of the marks where the melted, flowing spray collected into thicker little blobs, just as you would expect.

? These marks remind me very much of what it looks like when I have tried on a few occasions to use a leaf blower to dry up or blow away small puddles on water that dripped off of our cars onto the garage floor after a rain. The rainwater flows out into myriad array of streaks, with thicker "blobs" of water at the end of each of the streaks. I know that's not tremendously scientific sounding, but if any of you have ever done the same, you'll know what I mean. And I think that is essentially what happened on the meteorite. Some "inclusion" melted right at the surface, and the liquid was blown and scattered out into streaks, just like the leaf blower does to the rainwater on the garage floor.

???I feel very confident that this is what caused the streaks on the stone. Now I think the question is ------- WHAT mineral inclusion produces a "silvery-blue" liquid when melted????? I know some have suggested troilite (iron sulphide). That may very well be right, but does anyone know if that would be this color?? Or would it more of a "bronze" color, as the mineral itself is??? Once again, I do not want to make any wild claims here, but copper sulfate is blue. With that said, I also have to add that even though Ash Creek (West) has been proven to contain copper, I find it hard to believe that there would be a big enough "blob" of it to produce this large of an area of spray. But then again, most meteorites do not exhibit these markings, and several from this fall do. Also, IF ( and I said? " IF " ) this meteorite also is shown to have halite crystals, would they by any chance produce these marks upon melting????

??Finally, I have to admit I'm pretty intrigued by these markings. I've never seen anything like them before, but that's not saying a lot. BUT ----when Robert Haag says HE has never seen anything like this, that does seem to make it pretty unique.? Some other members have already said earlier that they have seen these marks on a few of their specimens. Have any additional members out there found them on any of their stones????

? If anyone has any further ideas on this, I'd love to hear them.?And thanks again to those of you who responded earlier.?

? Sincerely,
? Robert Woolard ?

?

???













      
Received on Wed 29 Apr 2009 01:23:36 AM PDT