[meteorite-list] Met Bulletin Update - Sau 559 (Ureilite)

[Galactic Stone & Ironworks]

Hi Bulletin Watchers,

One new approval today.  It is an old Oman find from 2005.  Apparently
this ureilite was very stubborn and it chewed up several blades before
it could be subdued by the saw.

Text -

Sayh al Uhaymir 559 (SaU 559)        20°33.046’N, 56°39.336’E

Al Wusta, Oman

Found: Nov 2005

Classification: Ureilite

History: During November 2005, John Blennert found a 107 g meteorite
in the desert of Oman.

Physical characteristics: Exterior of the stone is rough, with
preferential (wind?) ablation of the pyroxene over olivine grains.
Difficult to cut, requiring seven diamond blades and one week to slice
the stone in half. Surface of the polished thin section is rough.

Petrography: Typical ureilite dominated by roughly equal proportions
of anhedral, fine- to medium-grained (0.5 to 1 mm) olivine and
pyroxene. No graphite visible in the thin section. Extensive reduction
of the olivine. Diamond abundant and confirmed by powder X-ray
diffraction. Diamond clusters to 20 μm visible with a reflected-light
microscope. Interstitial metal mostly altered to iron oxides.

Geochemistry: Olivine and pyroxene more reduced than in typical
ureilites. Olivine cores have Fa5.2±0.1, FeO/MnO = 11.5±0.7, Cr2O3 to
0.5 wt%, CaO to 0.3 wt%, n=13, rims to Fa0.5. Low-Ca pyroxene cores
Fs4.7±0.1Wo4.89±0.04, n=7.

Classification: Ureilite.

Specimens: 32 g and one thin section at ASU.

Link - http://www.lpi.usra.edu/meteor/metbull.php?code=57462

Best regards,

MikeG
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