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28° 37' 42" N., 4° 43' 39" E.
Five individual masses with a combined weight of 10 kg were found in the Sahara Desert near the southwest tip of Ouargla Province in Algeria (Google Earth image), and these were subsequently purchased by M. Lyon. A type sample was submitted to the University of New Mexico's Institute of Meteoritics for analysis and classification (A. Ross and C. Agee; K. Ziegler, oxygen isotopes), and Hassi el Biod 002 was classified as an ungrouped pallasite.
The HeB 002 pallasite is composed of angular red-orange olivines (38 vol%) embedded in an FeNi-metal host (60 vol%), along with minor troilite (2 vol%). Other minor and accessory mineral phases commonly present in other pallasites were not observed in the classification analysis. The meteorite experienced low shock and exhibits moderate terrestrial weathering.
Hassi el Biod 002 and the three pyroxene pallasites Vermillion, Y-8451, and Choteau have similar O-isotopic compositions (see diagram below). Nevertheless, HeB 002 and Choteau have disparate olivine compositions (HeB 002: Fa7.7 [±0]; Choteau: Fa9.210.1/10.3 [±0.6]) and FeO/MnO ratios (HeB 002: 24 [±1]; Choteau: 2735/33.5 [±2.5]), which indicate they are not genetically related (MetBull and Gregory et al. ). Based on oxygen isotopes, Hassi el Biod 002, Vermillion, Y-8451, and Choteau all plot within the field of the acapulcoitelodranite clan (see plot 1 and 2). However, their differing mineral chemistry is inconsistent with any genetic relationship with the acapulcoitelodranite clan. Furthermore, it was demonstrated by Dey and Yin (2022 #2428) on a coupled Δ17O and ε54Cr diagram that Choteau is not related to Vermillion; Vermillion plots in a unique space between the winonaite and acapulcoitelodranite fields, while Choteau plots in the ureilite field (see the Vermillion and Choteau respective pages).
Oxygen Isotope Composition of Ungrouped Pallasites
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Diagram adapted from Gregory et al., 47th LPSC, #2393 (2016)
Based on all of the data gathered so far, it could be concluded that the pallasites in our collections represent at least ten separate parent bodies: (1) main-group high-Δ17O; (2) main-group low-Δ17O; (3) Eagle Station group; (4) Milton; (5) Vermillion + Y-8451; (6) Zinder + NWA 1911; (7) Choteau; (8) NWA 10019 ± Bordj Badji Mokhtar 001; (9) LoV 263; (10) Hassi el Biod 002. In addition, several pallasites with anomalous silicates (e.g., Springwater) and anomalous metal (e.g., Glorieta Mountain) could possibly increase the number of unique parent bodies. Proposed scenarios for pallasite formation can be found on the Imilac page. The specimen of Hassi el Biod 002 shown above is an 18.3 g partial slice, photography courtesy of Mark Lyon.