[meteorite-list] Free Nickel-Iron In Lunar Breccias

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:48:13 2004
Message-ID: <3BD7C457.587A19D3_at_lehrer1.rz.uni-karlsruhe.de>

Mark Fox wrote:

> With ... the long impact history of our scarred moon,
> wouldn't it be possible for some malleable, nickel-iron
> metal to be observed in lunar breccias from the impact
> of an iron or nickel-iron rich meteorite?


Hello Mark, Listees, and Listoids,

According to the Met. Bull. 81, 1997, p. A159, the
DaG 262 polymict anorthositic lunar highland breccia
is said to contain metal particles (5-26 wt% Ni) wthin
the fine-grained matrix of the breccia and within the
shock veins.

The accessory minerals of Dhofar 025, an anorthositic regolith
breccia, are silica, Ti-rich alumochromite, troilite, and FeNi
metal (Met.Bull. 84, 2000 August).

The accessory minerals of Dhofar 026, an anorthositic crystalline
melt breccia, are silica, ilmenite (MgO = 7 wt%), troilite, and
FeNi metal (Met.Bull. 84, 2000 August).

> ... has such an nickel-iron occurrence ever been recorded
> in any of the moon rocks recovered during the Apollo or
> Luna missions?

The accessory minerals of Dhofar 081 (and Dhofar 280 - they
are probably paired), a feldspathic fragmental (polymict clastic)
breccia, are Fe-Ni metal, ilmenite, and Ti-Cr-rich spinel
(Met.Bull. 85, Sep 2001).

Dhofar 287, a low-Ti, olivine-pyroxene mare basalt
breccia, also contains FeNi metal (Met.Bull. 85).

BECKER R.H. et al. (1994) Solar Wind Noble Gases and Nitrogen
in Metal from Lunar Soil 68501 (Meteoritics 29-5, 1994, 724):

The authors describe spherical meteoritic metal grains, which
are presumed to be droplets formed from impact-produced melts.


Best wishes,

Bernd
Received on Thu 25 Oct 2001 03:50:47 AM PDT