[meteorite-list] NEW Plutonic Angrite - NWA 4590 "Tamassint"

From: Rob McCafferty <rob_mccafferty_at_meteoritecentral.com>
Date: Thu, 12 Apr 2007 18:24:09 -0700 (PDT)
Message-ID: <243241.8760.qm_at_web50901.mail.re2.yahoo.com>

Amazing stuff Sterling. I'm thinking this makes
Angrites less likely to come from Mercury but does
anyone have a CRE of Angrites? I just had it in my
mind that it was only a few million to a few hundred
million years which I think puts another nail in the
coffin.
If they're 4000MYr or so then obviously I need to
remortgage my house and buy Greg's 30k chunk of this
new angrite.
I'm not accepting any ages of angrites from Greg or
his friends or family at this point. hehe!

Rob McC

--- "Sterling K. Webb" <sterling_k_webb at sbcglobal.net>
wrote:

> Hi,
>
> Here's a nice discussion of the FeO of Mercury:
> http://www.psrd.hawaii.edu/Oct01/MercuryMtg.html
>
> We used to think FeO was 5-6%; now the thinking
> is 2-3%, which gives us this interesting sequence
> for
> the inner planets: Mercury 3%, Venus 7%, Earth 8%,
> Mars 18% FeO, making an inverse relationship between
> FeO and the amount of iron in their cores (?).
>
> There's the suggestion that David mentioned,
> that it's
> old Mercurian crust from the Big Whack that's been
> hanging
> around for 4+ billion years. David said to Rob: "As
> you
> point out, this material would have to enter a
> stable orbit
> around the Sun until relatively recently." That
> sounds like
> he means a close inner system orbit.
>
> If you mean an inner solar system orbit, there
> is no
> stable place for a rubble collection, sunward
> asteroid belt,
> or other assortments of planetary leftovers that far
> downtown. And, oddly, the inner system has been
> searched for various supposed asteroids, the
> "Vulcanoids,"
> many times with no success.
>
> There is no quiet home life for small bodies in
> the
> inner system as long as there are large bodies in
> the
> neighborhood throwing, if not their weight, their
> gravity
> around. There IS a place where large collections of
> small
> bodies can persist for a long, long time, a giant
> junkyard
> and planetary leftover surplus yard from 1.6 to 4.2
> AU
> (more or less), called the Asteroid Zone.
>
> It is full of stuff from the inner system.
> Remember the
> recent SRI study that showed that the dynamics of
> the
> many large iron cores in the Zone demonstrate that
> they
> likely came from very close in (from sunward of
> Mercury
> out to sunward of Venus)? Of course, there no
> "identified"
> parent bodies, but that failing is common for many
> types
> of meteorites.
>
> A radical theory! Meteorites come from the
> Asteroid
> Zone!!! No, wait... Is that a new idea?
>
>
> Sterling K. Webb
>





       
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Received on Thu 12 Apr 2007 09:24:09 PM PDT