Abstract Volume, 2nd Congress of Società Geochimica Italiana “From theoretical to applied geochemistry”

Canyon Diablo (CD) meteorite, named after the impact crater in Arizona, was classified as an iron meteorite belonging to the IA group, Main Group (MG), as formed by a large contribution of chondritic processes [Walker, 2016, Worsham et al., 2016]. Although the Meteor Crater is widely studied [e.g., Kring, 2017], the literature dealing with the meteorite is sporadic and mainly focused on the silicate content and calcite veins [e.g., Hilton et al., 2020], indeed, the main body was almost completely vaporized in the impact and most of the few ejecta left melted within the surrounding lithologies. This contribution aimed to chemically characterize two Meteor Crater fragments, one (CdD1) already certified as a CD piece and one (CdD2) bought from an ecommerce network without any guarantees about the declared origin. The study focused on bulk and in‐situ analyses of minor and trace highly siderophile elements (HSEs) and platinumgroup elements (PGEs), combined with bulk C isotopic ratios measured in‐situ on the individual block, not on powder, such analytical procedure found no records of analogues in the literature. For both samples, the main mineralogical constituents were taenite-kamacite and rare sulfides. In addition, the two fragments showed the same major and trace element chemical composition, with Fe 91.3-91.6 wt.%, Ni 7.60-7.87 wt.%, and Pt 1.13-1.40 ppm, Au 2.58-6.74 ppm, in agreement with literature values for group IA iron meteorites [Hirata & Nesbitt, 1997], and for CD [Wasson & Ouyang, 1990, Hilton et al., 2020]. Therefore, both CdD1 and CdD2 are fragments derived from the same meteoritic body. Finally, it is important to note that, compared with the IA-MG group, CD fragments have lower Ni and Au contents, thus they could be classified as belonging to the subgroup IAB sLL. References Hilton C., Ash R., Piccoli P., Kring D., McCoy T., and Walker R., (2020). Origin and Age of Metal Veins in Canyon Diablo Graphite Nodules. Meteoritics & Planetary Science, 55, 771-780. https://doi.org/10.1111/maps.13464 Hirata T., and Nesbitt R., (1997). Distribution of platinum group elements and rhenium between metallic phases of iron meteorites. Earth and Planetary Science Letters, 147, 11-24. https://doi.org/10.1016/S0012-821X(97)00012-5 Kring D., (2017). Guidebook to the Geology of Barringer Meteorite Crater, Arizona (a.k.a. Meteor Crater) second edition. Lunar and Planetary Institute, LPI Contribution No.2040. Walker R., (2016). Siderophile Elements in Tracing Planetary Formation and Evolution. Geochemical perspectives, 5, 1-145. doi:10.7185/geochempersp.5.1 Wasson J., and Ouyang X., (1990). Compositional range in the Canyon Diablo meteoroid. Geochimica et Cosmochimica Acta, 54, 3175-3183. https://doi.org/10.1016/0016-7037(90)90132-5 Worsham E., Bermingham K., and Walker R., (2016). Siderophile element systematics of IAB complex iron meteorites: New insights into the formation of an enigmatic group. Geochimica et Cosmochimica Acta, 188, 261-283. https://doi.org/10.1016/j.gca.2016.05.019