Microtektites from Victoria Land Transantarctic Mountains

We report on the discovery of a microtektite (microscopic impact glass particles) strewn fi eld 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 defi ne a coherent population with a geochemical affi nity to Australasian microtektites and compatible Quaternary 40Ar-39Ar formation age. We therefore suggest that Transantarctic Mountain microtektites (TAMM) defi ne the southern extension of the Australasian strewn fi eld. The margin of the Australasian strewn fi eld 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 fi eld discovered on Earth. Furthermore, TAMM are depleted in volatile elements (i.e., Pb, Na, K, Rb, Sr, Rb, and Cs) rela tive 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.