Toksun 001        42°41.635’N, 88°37.129’E

Xinjiang, China

Find: 2020 Apr 3

Classification: Ordinary chondrite (LL6/7)

History: (Ziyao Wang) Discovered by Weiya Zhang and Baozhen Wan 3.5 km south of Toksan power plant, on Apr. 3, 2020. and was purchased by Ziyao Wang on Apr.12, 2020.

Physical characteristics: (Ziyao Wang) 16 kg gray black stone, with rather fresh fusion crust and regmaglypts. Cut face shows light fragments in a dark-gray matrix with tiny metallic specks and few greenish silicates.

Petrography: (R. Bartoschewitz, Bart) Breccia of light-gray subrounded granoblastic clasts up to 1 cm in black-gray cataclastic matrix. Granoblastic areas show heterogenous grain sizes of about 30-600 µm. Predominant phase is olivine, minor low-Ca pyroxene (<500 µm) and feldspar with interstitial interconnected texture (up to 600 µm) enclosing smaller olivine and pyroxene grains (including close packed aggregates of small spherical 10 µm olivine/pyroxene grains), few augite (<100 µm) with exsolution lamellae and accessory chromite (up to 200 μm). Sulfide <600 µm) and metal (<30 µm) occur as angular single grains. The cataclastic matrix is enriched in sulfide and metal, but stronger replaced by Fe-oxyhydroxides that fill the cracks. Few remnant relict chondrule fragments occur as well in the granoblastic as well as in the cataclastic area.

Geochemistry: (R. Bartoschewitz, Bart, P. Appel and B. Mader, Kiel) Microprobe results from the granoblastic and cataclastic areas are the same. Olivine Fa_30.4±0.6 (n=77); low-Ca pyroxene Fs_25.7±0.9Wo_1.5±0,3 (n=11); augite En₄₆Fs₁₀Wo₄₄ (n=4); feldspar An_10.5±0.6Or_4.8±0.9 (n=16); chromite CRAL=85, FFM=92 (n=4). Kamacite Ni=6-7 wt%, Co=0.7-0.9 wt% (n=3); taenite, tetrataenite, troilite, Ni-bearing pyrrhotite. Magnetic susceptibility (R. Bartoschewitz, Bart) log χ (× 10^-9 m³/kg) = 3.75. O-isotopes (A. Pack and T. Di Rocco, UGött): δ¹⁷O (‰) = 4.159, δ¹⁸O (‰) = 5.772, D’17O (0.528) = 1.111.

Classification: Ordinary chondrite (LL6/7, S4).

Specimens: 22.7 g on deposit at Kiel, Ziyao Wang holds the main mass, and 182 g plus polished thin section with Bart.