Chug Chug 086        22°29.66’S, 69°07.07’W

Antofagasta, Chile

Find: Oct. 2019

Classification: Ungrouped chondrite

History: one piece of meteorite (field number Chug-Chug 6-8) was found in the desert of Chile by Mr. T. V. Kryachko.

Physical characteristics: a sample of meteorite has a brown fusion crust.

Petrography: M. A. Ivanova (Vernad.) Meteorite consists of well-defined chondrules (~90%) and matrix (~10%), average size of chondrule is 283±270 μm, several chondrules, up to 4 mm, also occur. POP, OP and PP chondrules are abundant, BO and PR chondrules are rare; one Al-rich chondrule occurs in the section; CAIs are absent. Minerals are olivine, pyroxene, Fe,Ni-metal, troilite, silica, schreibersite, chromite and products of terrestrial weathering. Glass of plagioclase composition sometimes occurs in chondrules. Shock stage is S1, weathering grade is W3. Petrological type is 4, since olivine is homogeneous and chondrules are well delineated. However, glass in some chondrules indicates petrological type 3.

Geochemistry: Mineral compositions and geochemistry: M. A. Ivanova Olivine: Fa _2.13±0.08 (N=41), orthopyroxene: Fs _12.3±5.00 (N=38); Wo _1.21±1.20 (N=38), Fe/Mn = 21.2 ± 8.7 (N=38) , clinopyroxene is represented by pigeonite: Fs _10.5-27.5, Wo _6.6-14.8, augite Fs _2.6-22.4, Wo _30.3-43.7 and diopside Fs _1.0-9.2, Wo _46.0-49.6; plagioclase glass in chondrule has variable composition: Ab _9.7-83.4, Or _0.13-17.4; Fe,Ni-metal contains 6.37 wt% of Ni, 0.46 wt% of Co; sulfide is troilite. Oxygen isotopic composition (OU): δ¹⁷O 2.923, 2.949; δ¹⁸O 4.312, 4.464; Δ¹⁷O 0.714681, 0.628 (permil).

Classification: based on very reduced and homogeneous olivine composition (Fa_{2.13 ± 0.08}) and orthopyroxene of variable composition (Fs_3.4-22.5), this meteorite is ungrouped chondrite, although its oxygen isotopic composition, average chondrule size and Co content in kamacite are in the range of H chondrite. Homogeneous olivine, well-delineated chondrules and presence of glass in chondrules make difficult to determine petrological type of this chondrite.

Specimens: a fragment of meteorite (3.9 g) and 1 polished section are deposited in Vernad.