Yaratkulova        55°11’57"N, 60°25’53"E

Chelyabinskaya oblast’, Russia

Find: 3 May 2016

Classification: Ordinary chondrite (H5)

History: Meteorite was found on 3 May 2016 by Leonid B. Pudovkin and Sergei V. Kolisnichenko on pasture land (formerly plowed land), 3.5 km southwest of Yaratkulova (Argayash district, Chelyabinskaya oblast’). Seven fragments (190, 136, 33.4, 15.6, 16.0, 7.0 and 1.2 g) were found in the 5x6 m soil area at 3-12 cm depth. All fragments are easily integrated in single unit (399.2 g). The meteorite seems to have been broken on impact or during plowing of the land. The date of fall is unknown.

Physical characteristics: The meteorite has rounded to angular shape with apparent stream lines on one side. The surface of the meteorite is light to dark brown in color due to abundant Fe-hydroxides. The fusion crust occurs very locally. Parallel cracks (1-2 mm in thickness) are common on the larger meteorite fragments. Sometimes they are filled with Fe-hydroxides, rarely gypsum.

Petrography: Classification (V. V. Sharygin, SIGM and UrFU). Meteorite is a chondrite breccia, in which light to dark coarser-grained fragments (0.5-1.5 cm, 30 vol.%) are cemented by dark-brown shocked material (~70 vol.%). Troilite and metal are not abundant and most grains (>60%) are replaced by Fe-hydroxides (weathering grade – W3). The chondritic fragments show coarse- to medium-grained textures with local areas of recrystallized, fine-grained, granular texture. Chondrules (up to 1-1.5 mm) are still distinct, but occur rarely. This indicates a petrological type of 5 for the meteorite. It contains olivine, orthopyroxene, plagioclase (or maskelynite) and individual grains of troilite and metal. Clinopyroxene, chromite, chlorapatite and merrillite occur locally. Three sets of parallel, planar fractures, strong mosaicism, and planar deformation features in olivine and related orthopyroxene, rare polysynthetic twinning in pyroxene, and partial to complete maskelynization of plagioclase indicate a shock stage of S5. The shocked material contains small relics of initial chondrite and chondrules, areas with porphyritic texture (olivine + clinopyroxene-plagioclase skeletal aggregate), melt pockets with skeletal clinopyroxene, vesicles and dark impact melt, which occurs interstitially among the above lithological clasts.

Geochemistry: Mineral composition and Geochemistry: EDS-WDS analyses (C. V. Sharygin, SIGM and UrFU). The chondrite contains olivine Fa_20.3±1.3 (N=60), orthopyroxene Fs_18.9±1.2Wo_1.2±0.4 (N=51) and plagioclase Ab_83.8An_10.3Or_5.9. Cr-bearing clinopyroxene En_46.9Fs_8.0Wo_45.1, chromite Crt81.6, chlorapatite, merrillite, troilite and Fe-Ni-metals (kamacite, taenite, tetrataenite) are also present. Micrometer-sized grains of an SiO₂ polymorph in Opx-Cpx-Pl chondrule and sarcopside-graftonite globule in a kamacite grain were also found. Secondary weathering products are goethite, “hydrogoethite” and Fe-hydrosulfide, rarely gypsum and Fe-Ni-sulfate.

Classification: (V.V. Sharygin, SIGM and UrFU). Ordinary chondrite. H5, S5, W3.

Specimens: 25.7 g type specimen (UrFU), 33.4 g sample + 18.2 g cut-off fragments (Central Siberian Geological Museum at SIGM), and other pieces are in private collections (Sergei V. Kolisnichenko, Igor V. Karlov).