[meteorite-list] Never underestimate or dismiss Spectroscopy

From: cdtucson at cox.net <cdtucson_at_meteoritecentral.com>
Date: Thu, 17 May 2012 11:29:36 -0400
Message-ID: <20120517112936.YRCCR.709194.imail_at_fed1rmwml107>

Benjamin,
You may be right about Vesta and Eucrites but, without an actual sample return it is still merely an educated guess.
Even meteorites that are found within the same strewn field here on Earth require verification of pairing based largely on Oxygen Isotopes matching up.
Without this very important tool we would not have confirmation of any parent bodies including the Moon and Mars. So, it seems to me the most important verification needed is in fact Vesta. After all this is the one we think we have many samples of in our collections.
Albedo is great but, if we could verify from albedo alone we would already have matches for many planets and asteroids and we simply do not.
According to the latest probes of Mercury we still don't know what it's surface rocks would compare to in our collections. What if it ends up having the same Oxygen Isotopes as the Earth and Moon and Aubrites and some irons like IIIAB and IAB? This info would greatly advance our knowledge.
The Return of samples mission was chosen for Dante Lauretta's mission for a reason. We cannot state a good case for any origin without study (including isotopic) of return samples. Or at least remote study as we did with Mars.
Carl
meteoritemax
(520) 979-9865

--
Cheers
---- "Benjamin P. Sun" <bpsun2009 at gmail.com> wrote: 
> If a dealer or someone were to claim that their Tatahouine or NWA 2060
> came from Vesta, I would not counter or argue with him. Simply because
> he has more evidence and proof pointing his way now. You should say
> that the(<1%) rare odd non-Vestan ungrouped anomalous "eucrite" may or
> may not be from Vesta instead.
> 
> At this time, a sample return mission from Mars, Phobos, Europa or
> Titan would make more sense than a sample return mission from Vesta.
> 
> On 5/16/12, Benjamin P. Sun <bpsun2009 at gmail.com> wrote:
> > "Generally speaking, stating to the HED clan of meteorites are mainly
> > derived from "Vesta" is acceptable so long as we understand ( Caveat
> > #1) that they could also be from any of the Vesta family: any of
> > those 6000+ bodies populating the Vesta orbital region. Many of
> > those are over 1 km size and most but not all have Vesta matching
> > spectra/albedos."
> >
> >
> > I'd consider that the many Vestiods of the Vesta family were and are
> > still pieces of their parent body, Vesta. Not counting the odd
> > interloper or co-habitant of the group region, of course.
> > Just like the many martian and lunar meteoriods(martianiod? lunoid?)
> > out there floating in space, blasted off their PB's, were and still
> > are considered pieces of Mars and the Moon respectively.
> > Speaking for myself, it matters very little whether my HED came from
> > Vesta directly or indirectly from a Vestiod. In the end, it's still
> > from Vesta.
> >
> >
> > "The second caveat is covered elsewhere in recent list commentary: the
> > fact that we do have some non-Vestian eucrites was panned as
> > "insignificant". Well, Au contraire-- the existence of a but a
> > solitary example is proof that the "basaltic, sub/minor-planetary
> > differentiation process" happened on more than a single body. Adding
> > credibility to the planetary-science model. Naively stating over
> > and over that "all eucrites " come from Vesta" won't make it true.
> > Doing so retards the advancement meteorite science."
> >
> >
> > Keep in mind that the word "eucrite" and "eucritic" was a rather broad
> > and loosely used term back in the (old) day(s). Scientists now are
> > more specific in it's usage, accurate and clear with their
> > classifications . So some of those old eucrites and rare "non-Vestian
> > eucrites" need to be re-examined and possibly reclassified.
> >
> >
> > From Wikipedia:
> >
> > "Eucrites are achondritic stony meteorites, many of which originate
> > from the surface of the asteroid 4 Vesta and as such are part of the
> > HED meteorite group. They are the most common achondrite group with
> > well over 100 distinct finds at present.
> >
> > Eucrites consist of basaltic rock from the crust of 4 Vesta or a
> > similar parent body. They are mostly composed of Ca-poor pyroxene,
> > pigeonite, and Ca-rich plagioclase (anorthite)."
> >
> >
> > I happen to agree with this definition. Also:
> >
> >
> > "Eucrites get their name from the Greek word eukritos meaning "easily
> > distinguished". This refers to the silicate minerals in them, which
> > can be easily distinguished because of their relatively large grain
> > size.
> >
> > Eucrite is also a now obsolete term for bytownite-gabbro found on
> > Earth. The term was used as a rock type name for some of the Paleogene
> > igneous rocks of Scotland."
> >
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Received on Thu 17 May 2012 11:29:36 AM PDT