We report the discovery of large accumulations of micrometeorites on the Myr-old, glacially eroded granitic summits of several isolated nunataks in the Victoria Land Transantarctic Mountains. The number (>3,500) of large (>400 μm and up to 2 mm in size) melted and unmelted particles is orders of magnitudes greater than other Antarctic collections. Flux estimates, bedrock exposure ages and the presence of ≈0.8-Myr-old microtektites suggest that extraterrestrial dust collection occurred over the last 1 Myr, taking up to 500 kyr to accumulate based on 2 investigated find sites. The size distribution and frequency by type of cosmic spherules in the >200-μm size fraction collected at Frontier Mountain (investigated in detail in this report) are similar to those of the most representative known micrometeorite populations (e.g., South Pole Water Well). This and the identification of unusual types in terms of composition (i.e., chondritic micrometeorites and spherulitic aggregates similar to the ≈480-kyr-old ones recently found in Antarctic ice cores) and size suggest that the Transantarctic Mountain micrometeorites constitute a unique and essentially unbiased collection that greatly extends the micrometeorite inventory and provides material for studies on micrometeorite fluxes over the recent (≈1 Myr) geological past.

The new mineral chukanovite, Fe₂(CO₃)(OH)₂, occurs in cavities of weathered fragments of the Dronino ataxite iron meteorite found near the Dronino village, Kasimov district, Ryazan' Oblast, Russia. It is a product of terrestrial alteration of meteorite iron. Associated minerals are goethite, akaganéite, hematite, hibbingite, reevesite, honessite, etc. Chukanovite forms acicular to fibrous individuals (up to 0.5 mm long and up to 2–3 μm thick) combined in spherulites up to 1 mm in diameter, botryoidal spherulitic clusters and parallel- or radial-columnar aggregates which form crusts up to 1 mm thick. Unaltered chukanovite is transparent, pale-green or colourless. The surface of aggregates is brownish-green. Streak is white. Lustre is vitreous. Cleavage is perfect, probably on {0–21}, fracture is uneven. The mineral is brittle, the Mohs' hardness is 3.5–4, the calculated density is 3.60 g/cm³. It is optically biaxial (–) with α 1.673(3), β 1.770(5), γ 1.780(5), 2V _meas. 10(5)°. Average chemical composition (wt. %; electron probe, H₂O by modified Penfield method, CO₂ by selective sorption) is: MgO 0.1, FeO 68.8, NiO 0.6, CO₂ 19.8, H₂O 10.9, total 100.2. The empirical formula calculated on the basis of two metal atoms is (Fe²⁺ _1.97Ni_0.02Mg_0.01) _Σ2.00(CO₃)_0.93(OH)_2.14·0.18H₂O, ideally Fe₂(CO₃)(OH)₂. Chukanovite is monoclinic P2₁/a, with a = 12.396(1) Å, b = 9.407(1) Å, c = 3.2152(3) Å, β = 97.78°. The strongest lines of the X-ray powder pattern [d(Å), I, (hkl)] are: 6.14, 40, (200); 5.15, 60, (231); 3.73, 80, (310); 2.645, 100, (230); 2.361, 40, (510); 2.171, 40, (520). The structure of chukanovite was refined on synchrotron data by the Rietveld method up to Rp = 3.43 %, wRp = 4.51 %, R_Bragg = 2.48 %. Chukanovite is closely related to the minerals of the malachite-rosasite group. It was named in honour of Nikita V. Chukanov (b. 1953), Russian physicist and mineralogist. The holotype specimen is deposited in the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow.

We report on the discovery of a microtektite (microscopic impact glass particles) strewn field from the Victoria Land Transantarctic Mountains, Antarctica. Microtektites were found trapped in the local detritus accumulated in weathering pits and in joints of several glacially eroded summits (~2600 m above sea level [asl]) distributed latitudinally for 520 km. Their physical and chemical properties define a coherent population with a geochemical affinity to Australasian microtektites and compatible Quaternary ⁴⁰Ar-³⁹Ar formation age. We therefore suggest that Transantarctic Mountain microtektites (TAMM) define the southern extension of the Australasian strewn field. The margin of the Australasian strewn field is thus shifted southward by ~3000 km and the maximum distance from the putative parent impact site in Indochina by ~2000 km. This emphasizes the paradox of the missing parent crater of the largest (>10% of the Earth's surface) and youngest tektite strewn field discovered on Earth. Furthermore, TAMM are depleted in volatile elements (i.e., Pb, Na, K, Rb, Sr, Rb, and Cs) relative to Australasian ones, suggesting a possible relationship between high-temperature–time regimes in the microtektite-forming process and high-angle trajectories in the ejecta plume.