Material characteristics of dust fallouts during the dust-storm weather in Harbin: Constraint on the provenance

The dry- and wet-deposited dust depositions of the dust-storm event in Harbin on May 11, 2011 as well as the surface sediments from the potential sources were collected for investigation of grain-size, REE and Sr-Nd isotopic compositions. Some conclusions have been reached:The dry-deposited dusts are marked by bimodal grain-size distributions with fine mode at 3.6 μm and coarse mode at 28 μm whereas the wet-deposited dusts are indicative of unimodal grain-size modes with a fine mode at 6 μm. The grain-size modes for Harbin dust-storm dusts are compatible with CLP loess and Pliocene eolian red clay as well as the eolian dust entrained for a long distance in other regions of the world. These dust- storm depositions have a derivation from distinct sources. There are identical REE patterns and Sr-Nd isotopic compositions for dry- and wet-deposited dusts, suggestive of the derivation from Horqin Sandy Land and, to a certain extent, Onqin Daga Sandy Land. The corresponding Sr- Nd isotopic compositions for dry- and wet-deposited dusts give clues to suggest that fine grains in the CLP loess deposits are expected to be of derivation identical to coarse grains.