Calama 022        22°18.192’S, 68°33.0557’W

Antofagasta, Chile

Find: 2017 Oct 15

Classification: Ordinary chondrite (L6)

History: The meteorite (1 piece 12 kg and many smaller fragments) was found October 15, 2017 by Timur Kryachko.

Physical characteristics: Total mass is about 32 kg. Many similar meteorite framents were collected in area about 40 square meters. Largest stone (about 12 kg) ~12% covered by fusion crust. Fragments all have different shapes plus very rare fragments of fusion crust. The interior of the meteorite is light brown, whereas the surface is dark brown. Some cracks (up to 0.3 mm in thickness) are filled by alunite.

Petrography: (Pavel Yu. Plechov, FMMR). The main part of the meteorite contains many chondrules without clear borders. Chondrule sizes vary from 400 to 800 µm. Some chondrules (about 5%) have clear barred olivine textures, with plagioclase between the bars. Most of the chondrules consist of Ol+Opx with Cpx+Pl interstitial. Matrix consists of olivine and low-Ca pyroxene grains (70-200 µm) with aggregates of Ca-pyroxene and plagioclase. Plagioclase grains (An_10.4-10.8) are about 40-70 µm. These features indicate a petrologic type of 6 for the meteorite. Rare Fe-Ni metal blebs (up to 300 µm) and very rare troilite (up to 30 µm) occur in matrix. Metal consists of kamacite and taenite (with 35-53 wt.% of Ni). Olivine has no undulatory extinction; this plus the absence of opaque shock veins and melt pockets indicates a shock stage of S1. Weathering products (goethite, "hydrogoethite") occur as veins and in situ alteration of FeNi-metals. Troilite, olivine, pyroxene, chromite, metal are fresh and not weathered (weathering grade W1).

Geochemistry: Mineral composition and Geochemistry: EDS-WDS analyses (Pavel Yu. Plechov, FMMR). The primary chondrite paragenesis includes olivine Fa_25.35±0.56 (N=25), orthopyroxene Fs_20.7±0.7Wo_1.47±0.29 (N=21), plagioclase Ab_82.0An_10.6Or_6.7 (N=4), Cr-bearing clinopyroxene En_46.6Fs_9.1Wo_44.1 (N=2), chromite Crt_75.6Spl_9.1 (N=2) and Cl-apatite. No merrillite occurred in the meteorite. Composition of kamacite (in wt.%, N=1): Fe 93.78, Ni 5.25, Co 0.75. Taenite (N=4) contains 33.85 and 0.46 wt.% of Ni and Co, respectively. Troilite is close to ideal FeS.

Classification: (Pavel Yu. Plechov, FMMR). Ordinary chondrite. L6, S1, W1.

Specimens: Timur Kryachko, Ilya Kryachko, Mikhail Nepomiluev holds main mass about 32 kg. 60 g (7 small fragments) and thin section, FMMR.