Modern sedimentation system of Lake Untersee, East Antarctica

The paper presents data on the geographic and geological conditions of modern sedimentation in Lake Untersee, the largest lake in East Antarctica. Geochemical and sedimentation data indicate that the leading mechanism providing Al-Si sedimentary material to the surface layer of the bottom sediments is the seasonal melting of the Anuchin glacier and the mountain glacier on the southeastern face of the valley hosting the lake. The strongly reduced conditions in the lowermost 25 m of the water column in the smaller of the two depressions at the lake bottom were favorable for the enrichment of the bottom sediments in bacteriogenic organic matter, Mo, Au, and Pd. The H2S-contaminated water facilitates the significant enrichment of the sediments only in redox-sensitive elements able to migrate in the form of anionic complexes and precipitate (coprecipitate) as sulfides.