I would say it is likely an impact melt and not a fusion crust. It is not uncommon for impact melts to have unaltered clasts of the original material in them and well as small vugs formed from gasses in the melt. Nice photos John.
-- Eric Olson 7682 Firethorn Dr Fayetteville, NC 28311 http://www.star-bits.com ---- Kashuba <[EMAIL PROTECTED]> wrote: ============= Michael, Darren, Jim and list, I agree with Jim on this. My slice of the same stone has fragments set in a clearly bubbly melt. I suggest that this accumulated on the back side of the stone during oriented flight. Check out my pictures: http://www.johnkashuba.com/Pages/Meteorite%20Pages/Pictures/NWA2826LL5.htm Regards, - John John Kashuba Ontario, California -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Thursday, March 22, 2007 9:16 PM To: [EMAIL PROTECTED] Cc: Meteorite-list@meteoritecentral.com Subject: Re: [meteorite-list] Fusion crusts on stony meteorites Hi Mike and Darren, I probably would have had that response too without the benefit of turning these over in my hands and looking at them in 3 dimensions. I'm 99% sure that if you held these in your hands, and especially if you looked at them under the microscope, you would conclude the black areas are crust. This scan of reverse side of the 28 gram slide may be more convincing: http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCima lareversecl.jpg I also made an oblique photo of the other slice which shows the contiguity of the area with the fragments(lower right hand corner of the top photo, lower hand corner left of the lower photo) with the rest of the crust. http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueview-1 .jpg http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueviewre verse-1.jpg However, I'm sure I have about a thousandth the expertise of either of you so I could well be off base. Best wishes, Jim > I agree, I dont think that it is fusion crust, more > likely a brecciated section on the edge of the > meteorite. > Michael Farmer > --- Darren Garrison <[EMAIL PROTECTED]> wrote: > >> On Thu, 22 Mar 2007 21:58:51 -0400 (EDT), you wrote: >> >> >Hello Berndt et al., >> > >> >I thought you and the list members might find >> interesting a phenomenon >> >that was shown to me by Marcin Cimala. In cutting >> an LL5 he found areas >> >where thick crust had built up and actually >> incorporated within the crust >> >small angular fragments of relatively unaltered >> meteorite. Here are scans >> >of a slice I obtained from Marcin: >> > >> >>http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCi mala.jpg >> > >> >>http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCi malacloseup.jpg >> > >> >I assume that these fragments were dislodged late >> in flight while the >> >crust was still liquid but too late to be melted or >> thermally altered. >> >> I would think that is just a darker clast in the >> rock that happened to be only >> on the outer edge of that slice. >> ______________________________________________ >> Meteorite-list mailing list >> Meteorite-list@meteoritecentral.com >> > http://six.pairlist.net/mailman/listinfo/meteorite-list >> > > ______________________________________________ > Meteorite-list mailing list > Meteorite-list@meteoritecentral.com > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
