[meteorite-list] Asteroid Color Clans

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Thu Apr 22 10:06:14 2004
Message-ID: <20021107232624.9321.qmail_at_web11603.mail.yahoo.com>

Hi all -

It seems to me that instead of the meteorite classes
being tied to one particular asteroid, it is more
likely that ultimately the classes of meteorites (and
some sub-classes not yet separated out) will be tied
to classes of asteroids. In other words, in this
particular case the source may not necessarily Vesta,
but a Vesta-like asteroid.

If there are classes of asteroids, and my guessis that
it will turn out that there are, then you get into the
differentiation problem and the problem of parent body
size.

Wild stuff, but that's how I think this is going to
play out. Hopefully someday soon we'll probably see a
telescope actually placed within the "asteroid belt"
and we'll know the true state with certainty.

ep


--- John Divelbiss <j.divelbiss_at_worldnet.att.net>
wrote:
> Hi Al,
>
> Great stuff Al. As always, thank you for responding
> to my question and
> comments. You guys are going to force me back into
> the books to see what I
> read, but obviously didn't learn.
>
> As I remember it, the evidence with Vesta has to do
> with the large "gouge"
> in it's side that shows different levels of crust
> (eucrite) and sub crust
> (diogenite). This leads to another challenge or
> question, "if we think all
> or most of HED's come from Vesta, then why do they
> look so different from
> each other?". Some eucrites are white or grey, while
> others are a shade of
> light brown/yellow. The differences in diogenites
> are even greater. Is the
> new olivine diogentite thought to be from Vesta
> also?
>
> My answer would be "they sure could be". My
> experience in finding plutonic
> rocks here on earth is that the same area of
> exposure searched can have a
> wide variety (in appearance) of same type type rock.
> Some are more rich in
> one mineral than another...but for the most part
> still made up of the same
> ingredients. Temperature and pressure of the magma
> at one location versus
> another precipitates out minerals at different
> rates. Also the makeup of the
> magma then changes as it losses more of one element
> than others, changing
> the resulting rock formation mineral ratios. I
> think I answered my own
> question, but I'M WAY OVER MY HEAD HERE!!!
>
> HELP.....John
>
>
>
> ----- Original Message -----
> From: "almitt" <almitt_at_kconline.com>
> To: "John Divelbiss" <j.divelbiss_at_worldnet.att.net>
> Cc: "Bernd Pauli HD"
> <bernd.pauli_at_lehrer.uni-karlsruhe.de>; "Meteorite
> List"
> <meteorite-list_at_meteoritecentral.com>
> Sent: Tuesday, November 05, 2002 1:23 AM
> Subject: Re: [meteorite-list] Asteroid Color Clans
>
>
> > Hi John,
> >
> > I'll take a stab at this but Bernd really has
> great resources for
> answering this no
> > doubt better than I can. The topic that Bernd had
> started was on asteroid
> color clans
> > and that at least 90 percent of asteroids are
> associated with families
> (from
> > collisions in the past). No doubt the Vesta HED's
> are from chunks broken
> off from
> > Vesta in an impact and that have made their way
> into an orbit that upon
> further impact
> > has allowed meteoroids to end up in some of the
> kirkwood gaps where they
> can be
> > purbatrated into Earth crossing orbits. Yes they
> are from other sources
> but they
> > originated from the same source or asteroid. No
> doubt this is true for the
> other
> > related asteroid family groups and again the color
> clans that they are
> beginning to
> > piece together with the new research.
> >
> > I don't know if we can say for sure or not if a
> certain meteorite is from
> a particular
> > asteroid chunk or fragment but there is very
> strong evidence to show the
> HED's are
> > indeed from Vesta and also a strong link of the H
> type chondrites to
> asteroid Hebe. I
> > don't think there is much doubt about the Mars
> type meteorites (SNC's) are
> from Mars
> > and the Lunar meteorites are from the moon as we
> have been there and have
> material to
> > compare to. With the color clans coming into play
> we can at least say that
> certain
> > meteorites are from certain families now.
> >
> > On a related note Mar's moon Phobos is very
> similar to the CV3's like
> Allende but
> > there are also many other asteroids out there with
> that spectral match
> (could it be
> > the same clan?) I have always thought with the
> larger crater I see in the
> photos taken
> > by NASA that Phobos was a good candidate for that
> source material.
> >
> > Another question or comment. Perhaps some of the
> meteorites of different
> classes
> > sample the same asteroid (or family, clan). We
> could have iron meteorites,
> pallasites
> > and chondrites or achondrites all from the same
> parent body but we are
> looking at
> > different depths of material all from the same
> parent body or asteroid
> family clan.
> > This is no doubt true of the meteorites we have
> from Vesta and shows
> material from
> > different depths. My best!
> >
> > --AL
> >
> > John Divelbiss wrote:
> >
> > > Hi Al, Rob, Bernd and others,
> > >
> > > I think it is wonderful to think we can match
> types with asteroids that
> are
> > > labeled and watched.
> > >
> > > I have a question. Is it safe to say that what
> we are doing is matching
> > > spectrums of types with those same specturms for
> a given asteroid, but
> not
> > > necessarily committing to say that is probably
> from that asteroid. In
> other
> > > words, their maybe(must be) several to hundreds
> of a given type asteroid
> out
> > > there. And that one LL4 could come from one
> rock, and another from a
> > > different rock with the same spectrum on the
> opposite side of the belt.
> I
> > > maybe stating the obvious, but for instance I so
> often read that an HED
> is
> > > probably from the asteroid Vesta, when in truth
> it maybe from another
> one.
> >
> >
>
>
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Received on Thu 07 Nov 2002 06:26:24 PM PST