Amazing piece with bubbles Jason, Been trying to figure out how that could happen. It does not look like it happened due to melt during the fall but more like a feature from pre-entry, exposed after fragmenting.
What are your thoughts...I can't think of any other irons with bubbles. Regards Graham ---- Jason Utas <[email protected]> wrote: > Maurizio, Graham, Jeff, Fred, Darren, All, > I think Darren's hit on the fact of it - as I noted in my original post: > > "Many batches of shrapnel do appear to be somewhat ablated due to the > method by which they have been cleaned (tumbling with ball bearings > tends to wear corners down and gives the false impression of surfaces > having melted)." > > I think this is what you're noting, Fred - if you'd care to send some > pictures I'd be more than glad to have a look, but I'm fairly certain > that what you're seeing are mere remnants of the cleaning process. > Which isn't to say that shrapnel can't exhibit folded over rims, etc, > but such features are morphologically distinct from roll-over lipping > that we see in fusion crusts; it's one thing to fold a torn edge over, > and another matter entirely to force molten material over an edge to > form a lip. > I can't comment on the other features you've noted without seeing > pictures, but I would note that many Sikhotes exhibit crater-like > features that formed due to spallation caused by rust, which could > also be mistaken for bubbling. > I have only ever seen true bubbles on one Sikhote (and it is the only > *iron* meteorite that I've ever seen that actually showed true > bubbles) in my entire life; here's a photo. > > http://www.flickr.com/photos/cameteoritefinder/2335708513/sizes/l/ > > Regards, > Jason > > On Tue, Nov 17, 2009 at 12:08 PM, <[email protected]> wrote: > > Darren, I just looked at 119 individual pieces of shrapnel fragments under > > a microscope. They are rather small and range in size from 30 grams to less > > than one gram. It looks to me that every one of them shows some feature of > > melting. many have roll over rims, melted grooves, fusion crust with impact > > pits, bubbly crust on backside of oriented pieces. I doubt that any of > > these features were produced by tumbling. > > Regards, Fred > > -------------- Original message ---------------------- > > From: Darren Garrison <[email protected]> > >> > >> I was under the impression (read it somewhere) that most modern=collected > >> Sikhote-Alin fragments are rusty and are cleaned in rock tumblers. If so, > >> could > >> not that dull/round formerly sharp edges and make them look "melted"? > >> ______________________________________________ > >> http://www.meteoritecentral.com > >> Meteorite-list mailing list > >> [email protected] > >> http://six.pairlist.net/mailman/listinfo/meteorite-list > > > > > > > > > > > > ______________________________________________ > > http://www.meteoritecentral.com > > Meteorite-list mailing list > > [email protected] > > http://six.pairlist.net/mailman/listinfo/meteorite-list > > > ______________________________________________ > http://www.meteoritecentral.com > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
