Provenance, transport and characteristics of modern aeolian dust in western Gansu Province, China, and interpretation of the Quaternary loess record

Results of a comparative analysis of a 4-year set of monthly samples of airfall dust with samples from surface alluvial fan deposits, desert sand dunes and late Pleistocene loess and palaeosols in Gansu Province, northern China, are summarized. They suggest a qualification of the conventional view that the sand deserts were the primary single source of the Quaternary loess. It is argued that silts deflated from the surfaces of the large and numerous piedmont alluvial fans in the Hexi Corridor, Gansu, constituted a major contribution to the loess column in the western region of the Chinese Loess Plateau. The present dust fall regime in the Hexi Corridor suggests that distribution and rate of accumulation of airfall silt in the present interglacial is similar to that in parts of the Pleistocene loess record.