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| Bir Ounane 001 | |||||||||||||||||||||||||||||||||||||
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| Basic information | Name: Bir Ounane 001 This is an OFFICIAL meteorite name. Abbreviation: There is no official abbreviation for this meteorite. Observed fall: No Year found: 2022 Country: Mali Mass:  80 kg | ||||||||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 15 approved meteorites classified as Achondrite-prim. [show all] Search for other: Primitive achondrites | ||||||||||||||||||||||||||||||||||||
| Comments: | Approved 11 Dec 2022 | ||||||||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 111:
Bir Ounane 001 21.8453583, -3.248689 Gao, Mali Find: 2022 Classification: Primitive achondrite History: This meteorite was found approximately 118 km southeast of Taoudenni by Sahrawi meteorite hunters who were on a trip in search for meteorites. The locality is Bir Ounane is approximately 84 km southwest of the find location. Physical characteristics: Multiple identical appearing stones totaling 80 kg with the largest piece weighing 9883 g. Irregular shaped dark brown exterior with patches of smooth black fusion crust preserved. Freshly broken surfaces reveal a fine mix of dark gray and orange-brown grains, some oxidized patches are present. Petrography: (A. Ross and C. Agee, UNM) Reflected light microscopy and electron microprobe analysis show a granoblastic texture of silicates: forsterite (30-40%), enstatite (40-50%), diopside (10-20%), and andesine plagioclase (5-10%). Most silicate grains are less than 500 microns in diameter. Kamacite and oxidized iron make up approximately 5-10% of this meteorite, although most of the metal has been altered so estimates of the original kamacite abundance are uncertain. Minor phases include troilite (Cr-free), daubréelite, and schreibersite. Numerous oxidized crosscutting veinlets are present throughout. Geochemistry: (A. Ross and C. Agee, UNM) Forsterite Fa1.2±0.1, Fe/Mn=4±0, n=6; enstatite Fs1.5±0.2Wo0.8±0.1, n=3; diopside Fs0.7±0.0Wo41.5±0.1, n=3, andesine An38.5±1.1Ab61.1±1.1, n=4. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ18O= 5.760, 5.339, 4.915; δ17O= 1.698, 1.443, 1.190; Δ17O= -1.344, -1.376, -1.405 (linearized, all per mil, TFL slope=0.528). Classification: Primitive achondrite not belonging to a known group. This meteorite is an olivine websterite. The magnesian silicates and presence of daubréelite are like that found in winonaites. The abundance (~5-10%) of kamacite and oxidized iron more resembles metal abundances in acapulcoites/lodranites. The relatively fine grain size would be consistent with either winonaites or acapulcoites, but not lodranites. Δ17O is consistent with acapulcoites/lodranites, however δ18O is higher than the typical range for acapulcoites/lodranites. The triple oxygen isotope values are unlike those of winonaites. Specimens: 109.3 g including two probe mounts on deposit at UNM, Bachir Salek holds the main mass. | ||||||||||||||||||||||||||||||||||||
| Data from: MB111 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||||||||||||
| Institutions and collections |
UNM: Institute of Meteoritics
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126
USA, United States; Website (institutional address; updated 12 Feb 2015) |
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| References: | Published in Meteoritical Bulletin, no. 111, in preparation (2022)
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Geography:
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Statistics: This is 1 of 25 approved meteorites from Gao, Mali (plus 1 unapproved name) This is 1 of 97 approved meteorites from Mali (plus 2 unapproved names) | ||||||||||||||||||||||||||||||||||||
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