Calama 010        22°24.643’ S, 68°34.622’ W

Antofagasta, Chile

Find: 2017 Oct 15

Classification: Ordinary chondrite (H6)

History: The meteorite was found 15 October 2017 by the UrFU meteorite expedition-2017 in Chile (Pastukhovich A.Yu., Larionov M.Yu., Kruglikov N.A., Kolunin R.N.) near Chiu-Chiu, Calama region.

Physical characteristics: The meteorite has roughly rounded shape. Exterior of the stone is desert polished. The surface and interior of the meteorite is light to dark brown in color due to Fe-hydroxides. No fusion crust was observed.

Petrography: Classification (V. V. Sharygin, SIGM and UrFU). Petrographic observation of a polished thin section shows very rare chondrules in a coarse recrystallized matrix. Chondrules are very poorly delineated with apparent size to 2 mm. The POP chondrules are common and mainly consist of olivine, low-Ca-pyroxene and plagioclase, diopside, and ±chromite and blebs of troilite and FeNi-metal. Olivine, low-Ca-pyroxene and plagioclase are main minerals in matrix. Plagioclase grains are larger than 50-100 µm. This indicates a petrological type of 6 for the meteorite. Undulatory extinction and irregular fractures in olivine, as well as the presence of opaque shock veins, indicate a shock stage of S3. Majority of grains of FeNi-metal (100-800 µm) are mainly represented by kamacite; taenite and tetrataenite are rare. Sizes of troilite grains are 50-300 µm. Weathering products (goethite, Fe-Ni-Cl-hydroxide and other Fe-Ni-hydroxides, gypsum) occur as in situ partial alteration of FeNi-metals and troilite and fill microfractures in minerals from matrix and chondrules (weathering grade – W2). Nickel (1-3 µm) was found in abundant Fe-Ni-Cl-hydroxide-goethite aggregate around tetrataenite. Pentlandite (up to 10 µm) is rarely observed in troilite. Clinopyroxene, chromite, chlorapatite and merrillite (50-300 µm) occur locally in the matrix. Opaque shock veins are locally abundant and contain troilite (±Fe-Ni-metal) blebs in fine-grained olivine-orthopyroxene±clinopyroxene aggregate.

Geochemistry: EDS-WDS analyses (V. V. Sharygin, SIGM and UrFU). The primary chondrite paragenesis includes olivine Fa_19.33±0.35 (N=29), orthopyroxene Fs_16.96±0.28Wo_1.46±0.20 (N=25), plagioclase Ab_83.9An_10.5Or_5.6 (N=25), Cr-bearing clinopyroxene En_45.9Fs_7.6Wo_46.5 (N=3), chromite Crt_80.4Spl_14.9 (N=15), chlorapatite, merrillite, and FeNi-metals. Chlorapatite contains F (up to 1.1 wt.%); Cl – 4.87 wt.% (N=11). Merrillite is poor in FeO (0.5-0.9 wt.%, N=12). Composition of metals (in wt.%): kamacite (N=23) – Fe 92.85±0.41, Ni – 6.60±0.42, Co – 0.84±0.09; taenite (N=43) – Fe 60.31, Ni 39.38, Co 0.28; tetrataenite (N=1) – Fe 50.55, Ni 49.17, Co 0.14. Fe-Ni-Cl-hydroxide (N=5, in wt.%): FeO - 59.37, NiO – 11.91, CoO – 0.75, Cl – 16.83.

Classification: Ordinary chondrite. H6, S3, W2.

Specimens: 1189.29 g (18 pieces) at UrFU; 53.8 g sample and thin section at SIGM.