[meteorite-list] Met Bulletin Update : Martian Iron Meteorites

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Tue, 21 Nov 2017 12:22:15 -0500
Message-ID: <CAKBPJW_Eu4SAf2CoS247OBg7LXMsFiQurErbbc6q=DLhRL7WSg_at_mail.gmail.com>

MARTIAN IRON METEORITES officially approved by NonCom and published in
the Met Bull today. Interesting meteorites discovered by NASA's
Curiosity rover on Mars.

Text from the write-up on Aeolis Mons 001 :

Aeolis Mons 001
Mars : (-4.70156176, 137.3560462)
Find: 2016 Oct 30
Classification: Iron meteorite

History: The MSL rover Curiosity observed a very small rock informally
named Egg Rock (Henceforth Aeolis Mons 001), on sol 1505. The rock was
about 2.5 m from the rover, which was close enough to interrogate with
Mastcam and ChemCam (LIBS chemical analysis and RMI). Aeolis Mons 001
is small (4-5 cm) rounded, and apparently hemispherical. It was seen
only from one side. Another small fragment in the same rover location
appears in MastCam imagery, identified by multispectral analysis
(Wellington et al., 2017) but was not further investigated.

Physical characteristics: Aeolis Mons 001 has a lustrous blue-gray
color and contains oval shaped depressions consistent with regmaglypts
as well as elongated hollows that could result from ablation during
entry or in situ differential erosion of less-resistant inclusions. At
high resolution, the surface is smooth. The mass of the meteorite is
estimated to be ~250 g.

Geochemistry: Mastcam color images reveal the presence of subtle
surface patches on the surface, consistent with ferric materials,
while other regions have reflectance spectra consistent with
laboratory spectra of fresh iron meteorites (Johnson et al. 2016,
Wellington et al. 2017). Chemistry and mineralogy consistent with iron
meteorites are inferred from ChemCam analyses. Aeolis Mons 001 was
interrogated using a 3x3 ChemCam Laser-Induced Breakdown Spectroscopy
(LIBS) raster with accompanying Remote Micro-Imager (RMI) images.

The ChemCam elemental spectra show both iron and nickel peaks at all
nine points (Meslin et al., 2017). Comparison of these spectra with
spectra measured on several iron meteorites with a replica of ChemCam
in the laboratory at the Institut de Recherche en Astrophysique et
Plan?tologie (IRAP) indicate that Aeolis Mons 001 is mostly made of
kamacite and contains ~8 wt. % Ni. One point (#9) along the edge of an
elongated cavity also exhibits P peaks and is enriched in Ni (Fig. 3).
The colocation of Fe, Ni, and P in point #9 suggests the presence of
schreibersite, (Fe,Ni)3P on the rim of this cavity.

Classification: Iron meteorite

Specimens: Left in situ on Mars

Met Bull Link to all four new Martian meteorites
 - https://www.lpi.usra.edu/meteor/metbull.php?sea=aeolis&sfor=names&ants=&falls=&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=name&categ=All&mblist=All&rect=&phot=&snew=1&pnt=Normal%20table&dr=&page=0

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Received on Tue 21 Nov 2017 12:22:15 PM PST