NWA 6963

NWANorth West Africa
Find, 2011
Martian shergottite
Complete specimen, 107,9g
Size: 6,5 x 3,8 x 3,5 cm

History:
(H. Chennaoui Aoudjehane, FSAC) In September, 2011, a Moroccan meteorite hunter found the first pieces of NWA 6963 and sold it to A. Habibi without giving the exact provenance. The hunter continued collecting pieces in the same area for about 6 months. In mid-May, 2012, the NWA 6963 locality, near the river Oued Touflit, became widely known and hundreds of meteorite hunters went to the area searching for more pieces. Pieces ranging from 100 to 700 g have been recovered, as well as a few small pieces (3-10 g), most of them are broken and partially covered by a thin fusion crust. The total mass may be as much as 8-10 kg. This meteorite has almost the same composition as the famous martian meteorite Shergotty

Physical characteristics:
The original recovered material was a shiny, dark, 83 g fusion-crusted stone in three pieces. Minimal weathering. Interior shows abundant maskelynite and shock melt vein.

Petrography:
(C. Agee, UNM) Microprobe examination of a polished epoxy mount shows 60% pyroxene, 35% maskelynite, 2% ulvöspinel, 2% melt pockets with silica, minor merrillite, trace chlorapatite and pyrrhotite. Pyroxenes show core-to-rim zonation. Pyroxene grains 200 μm to >1 mm, maskelynite domains 50 μm to >1 mm.

Geochemistry:
(C. Agee and N. Wilson, UNM) Two distinct pyroxene compositional trends. Pigeonite Fs29Wo11En59 to Fs58Wo16En26, average: Fs39.7±7.7 Wo13.0±2.3 Fe/Mn=33±3 N=108. Augite Fs21Wo34En45 to Fs39Wo31En30, average: Fs 28.1±6.2 Wo 31.6±1.9 Fe/Mn=31±3 N=24.Maskelynite Or 2.3±0.7 Ab 48.3±2.1 An 49.4±2.6 N=9. Oxygen isotopes (Z. Sharp, UNM): δ18O=4.332; δ17O=2.528; Δ17O=+0.241 (all per mil).

Classification:
Achondrite (Martian, shergottite); minimal weathering, high shock grade based on complete transformation of plagioclase to maskelynite. Pyroxene compositional trends are similar, but not identical to Shergotty.

Specimens:
17 g including microprobe mount on deposit UNM. AHabibi holds the original recovered mass.

Reference:
Meteoritical Bulletin Database


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