Re-2: [meteorite-list] Mercurian origin of NWA 011

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Thu Aug 19 04:35:34 2004
Message-ID: <DIIE.00000032000026C3_at_paulinet.de>

> Help me out here...I thought mean density(of 5 or so) meant
> that the average for the body included the core. And that Earth
> was about 5 also with the surface around 3 and the core around
> 7 or 8....with a lot of 5 rocks in between. Our basalts are also
> in the 3.3 range are they not?


Hello John and List,

Of course, you are right and I stand corrected. A.E. Rubin, too, was kind
enough to direct my attention to my rash conclusion and in a private mail
to me, he wrote:

"Of course, the mean density of the planet Mercury with its enormous
iron core is not the value expected for basalts that erupted on the
planet's surface. Alan Rubin"

But there is another problem that is not too far away from all this: the FeO
content of NWA 011. According to Yamaguchi et al., NWA 011 is very rich
in FeO and although Palme H. proposes that NWA 011 may be a fragment
of Mercury, its high FeO content is problematic because this would point
toward a parent body with a small metallic iron core whereas Mercury is
believed to have a large iron core (See also A.E. Rubin's comment of an
"e n o r m o u s iron core").

References:

BURBINE T.H. et al. (2002) Spectra of extremely reduced assemblages:
Implications for Mercury (MAPS 37-9, 2002, pp. 1233-1244)

PALME H. (2002) A new solar system basalt (Science 296, 271-273).

YAMAGUCHI A. et al. (2001) Northwest Africa 011,
A New Basaltic Meteorite (MAPS 36-9, 2001, A228).


Best regards,

Bernd
Received on Thu 19 Aug 2004 04:35:32 AM PDT