[meteorite-list] Meteorite or Meteorwrong?

From: cdtucson at cox.net <cdtucson_at_meteoritecentral.com>
Date: Wed, 20 May 2009 10:15:37 -0700
Message-ID: <20090520131537.XL7D2.17553.imail_at_fed1rmwml38>

-Mark,
This is one of the things I miss most about David Kring being out of the Biz of classifications. He was the one that was always willing to take the time to show you and explain exactly what you were looking at. He is with NASA now But he used to frequent the Tucson show when he lived here.
To your other points; It seems to me the question was "is this a meteorite"? IMHO I see a rock that could be one if it came from space. So, is that fusion crust or not? David showed me multiple examples of Desert varnish It actually looks very little like fusion crust. Desert varnish is very thin and being just a residue of manganese it is very dull or flat black and rarely shiny. Whereas fusion crust always has some heft to it. you can easily see real thickness on a cut section. It is always a measurable thickness where Desert varnish requires a microscope to see it's thickness. Another imposter is Magma stuck to the outside of the rock. Magma is usually too thick to be fusion crust but again fairly easy to recognize once a you have seen the difference in person. To this point I wish Science would recognize that some of us do know this and would never confront them unless we had considered these factors.
So, I ask is this fusion crust I see? Where was it found? Was it on the living room floor under a big hole in the roof or was it in a field with no other rocks around? Mars for example has plenty of basalt and andesite. IMy 2 cents.
Carl Esparza
IMCA 5829


--- Mark Bowling <minador at yahoo.com> wrote:
>
> I was mostly going by color. Basalts tend to be darker, and granitic rocks are very light in color. But it's really hard to look at photos... Having it in hand would be much easier (a necessity really).
>
> I would be interested in learning what a professional would consider when faced with such a rock... It would be cool if someday the IMCA could host an ID workshop, maybe one year at Tucson or one of the European shows (where you're guaranteed a group of possible participants).
>
> Mark
>
> --- On Wed, 5/20/09, Michael Fowler <mqfowler at mac.com> wrote:
>
> > From: Michael Fowler <mqfowler at mac.com>
> > Subject: Re: [meteorite-list] Meteorite or Meteorwrong?
> > To: meteorite-list at meteoritecentral.com
> > Cc: "Michael Fowler" <mqfowler at mac.com>
> > Date: Wednesday, May 20, 2009, 7:20 AM
> > Most andesites have
> > phenocrysts.? This one doesn't.? Still could be
> > andesite, but maybe not.
> >
> > Mike Fowler
> > Chicago
> >
> >
> > > Mark B.>>I'd have to say andesite (definitely
> > not granite). <<
> > >
> > > Well...after some page turning and googling etc, I
> > have to now agree with
> > > Mark that this rock is probably some sort of
> > andesite...and definitely not
> > > granite. I've never seen so many different rocks that
> > I formerly simply
> > > referred to as granite. :O) I haven't found a totally
> > matching photo of
> > > andesite to the photo eric referred to, but the
> > literature gave me the impression
> > > that andesite is what he has or is at least a good
> > guess.
> > > GeoZay
> > >
> > >> Looks like a fine grained basalt covered with
> > desert varnish.
> > >>
> > >> I see no fusion crust (flow lines etc.) and no
> > regamaglypts. In the
> > >> cut surface, no metal, no chondrules, and no heat
> > affected zone.
> > >>
> > >> Mike Fowler
> > >> Chicago
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Received on Wed 20 May 2009 01:15:37 PM PDT