Reconstructing Early Jurassic plains of accumulation from occurrences of diamonds in present drainage network

In the southern Siberian Platform, diamonds were concentrated in placers along margins of lacustrine-alluvial plains during Jurassic tectonism and alluviation. Subsequent stages have been denudational, and the distribution of diamond deposits can be used in reconstructing pal eodrainage patterns, locating now-eroded source areas, and determining transport conditions. The Angara- Prisyan, Ilim-Nepa, Tychan-Vel'ma, Katanga, and Vilyuy diamond provinces are delineated on the basis of weight and degree of mechanical weathering of the crystals, indicating distance of travel and possible location of source area. — P. W. Wood.