Grain-size characteristics and genesis of the Huangshan Loess in Songnen Plain Area

Huangshan Loess makes a typical example of Northeast China's loess deposition, studying its genesis is the key to reconstruction of both paleoclimate and paleoenvironment of Northeast China. A high resolution and systematic grain size analysis is carried out on Huangshan Loess in Harbin area, and the origin of Huangshan Loess is discussed in this paper in comparison with many other types of sediment including the modern dust deposition in Harbin area, the loess-palaeosol distributed over the Loess Plateau, the fluvial sediment and Qidingshan Loess in Dalian. The results show that: the 10-50 μm partial group is the dominant group of the Huangshan Loess whereas the content of 50 μm and 5-10 μm particals, corresponding with the composition characteristic of typical eolian loess; The grain-size frequency distribution presents even-number peak and each of these features of grain size parameters are characterized by the atmospheric dust, the average of the σ, SK, KG, Kd, Mz, Md is 1.83, 0.21, 0.86, 2.01, 6.25φ, 5.89φ, respectively; Clay-silt-sand triangular plots of Huangshan Loess indicate that it belongs to clayey silt. C-M, L-M, A-M charts and statistical indices of grain size distribution share similarities with various aeolian sediments while obviously differ from fluvial sediments. No one discriminant analysis results is of positive value, which confirms that the Huangshan Loess is of the atmospheric sediment just like the aeolian origin of the loess-palaeosol in the Chinese plateau. © 2015, Editorial Department of Earth Science-Journal of China University of Geosciences. All right reserved.