Particle size characteristics of surface sediments and their environmental significance: a comparative study of deserts in arid western Inner Mongolia, China

Based on the analysis of particle size mechanical composition and parameter distribution of surface sediments in the Hobq Desert (HD), the Ulan Buh Desert (UBD) and the northern part of the Mu Us Desert (MUD) in western Inner Mongolia, and combining the sedimentary environment discrimination method and the particle size lognormal fitting method, this research compares and explores the particle size characteristics and the significance of sensitive components in the sedimentary environment to the provenance in the three deserts. The results are shown as follows: (1) Sediment samples in the HD are dominated by fine sand (48.9%), in the UBD by fine sand and medium sand (41.10% and 42.90%, respectively) and in the MUD by medium sand (41.62%). (2) \(\sigma_{1}\) and \(S_{K1}\) in the HD and the UBD are well sorted and symmetric, but are averagely sorted and show highly positive skewness in the MUD. (3) The sediment samples in the HD and the UBD are mainly aeolian sediments, with lacustrine sediments being secondary. By contrast, the sediment samples in MUD is largely made up of lacustrine deposits. (4) By fitting the particle size frequency curves of all samples, five components, namely C1, C2, C3, C4 and C5 ranging from fineness to coarseness, are obtained. It is also indicated that the sediments in the study area do not undergo a wide range of mixing, but mainly experience in situ sedimentation. The most of these sediments may belong to lakeshore deposits that have been modified by wind for a long time, and are accompanied by long-distance westerly dust, weathered debris from bedrock, and active paleosand dunes of riverbed sediments.