Microtektites from Vicoria Land transantartic mountains.

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 south- ward by ~3000 km and the maximum distance from the putative parent impact site in Indo- china 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. Further- more, 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.