10Be in desert sands, falling dust and loess in China

Cosmogenic 10Be is produced in the atmosphere, and deposits onto the surface of the earth mainly through wet precipitation and dust. Based on the analysis of 10Be in Chinese loess, we believe that 10Be in loess is composed of two components: locally precipitated atmospheric 10Be, and windblown 10Be adsorbed on the surface of silt grains. On the Loess Plateau, 10Be concentrations in loess and paleosol range from (1.4 to 2.8) × 108 atoms/g and (2.7 to 4.5) × 108 atoms/g, respectively. To investigate the sources of 10Be in loess, we measured 10Be in sand grains from deserts in western China and falling dust from the deposition regions. The results show that the 10Be concentrations in sand and dust are (1.1–5.1) × 107 atoms/g and (1.3–2.8) × 108 atoms/g, respectively. Loess and paleosol on the Loess Plateau both contain inherited 10Be adsorbed on silt grains from dust; most of the windblown deposited loess materials do not directly come from the Gobi and other sand deserts, but mainly from the loess–desert transitional zones, which are characterized by silt and dust holding areas.