A comparative analysis between local soils and dust deposition on snow in Shenyang, China and implications on loess-palesols evolution

Authors: SUN, ZHONG - Shenyang Agricultural University; JIANG, YING - Shenyang Agricultural University; WANG, QIU - Shenyang Agricultural University; SUN, FU-JUN - Shenyang Agricultural University; ZHANG, MENG-GE - Shenyang Agricultural University; Owens, Phillip; LIBOHOVA, ZAMIR - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2019
Publication Date: 2/2/2019
Citation: Sun, Z.X., Jiang, Y.Y., Wang, Q.B., Sun, F., Zhang, M., Owens, P.R., Libohova, Z. 2019. A comparative analysis between local soils and dust deposition on snow in Shenyang, China and implications on loess-palesols evolution. Geoderma. 342:34-41. https://doi.org/10.1016/j.geoderma.2019.02.005.
DOI: https://doi.org/10.1016/j.geoderma.2019.02.005

Interpretive Summary: Soils form within many types of geologic material. Fertile soils of the Midwest and many places around the worlld form in windblown silt material called loess. This loess material is basically dust accumulation over long periods of tme. This paper focuses on a fresh loess deposit in China to understand the original mineral and chemistry found in the material prior to becoming soil. OBy understanding the orginal material, we can observe older soils to understand the changes that occur over time. Once we gain a better understanding of the loess material, scientists can determine the area where the dust originated, how this material relates to climatic differences and how to best manage loess soils today. This paper was able to identify the likely location of the dust origins and how that dust traveled long distances to be deposited on the landscape.

Technical Abstract: Loess deposition from wind is one of the major sources of soil development in many regions including northeastern China. The dust deposition on snow from 6 sites in Shenyang, northeastern China was collected and characterized physically and chemically to determine its origin (modern vs. re-deposited loess). The origin and characteristics of the dust deposition were evaluated through comparisons with possible sources of sand desert areas based on elemental compositions, such as the A-CN-K (Al2O3-CaO+Na2O-K2O) ternary plot and ratios of Al2O3/TiO2, Fe2O3/TiO2, and Fe2O3/Al2O3. The texture and composition results showed that the dust deposition was most recent and not re-deposited loess. The dust deposition was predominantly silt-sized grains (2–50 µm) and had greater amounts of Na2O (1.7% vs. 1.5% average), MgO (2.1% vs. 1.2%), and CaO (3.2% vs. 1.2%) when compared to the local soil. Its mineral composition was mainly quartz, feldspar, and mica. The magnetic susceptibility of the dust deposition was 30.9×10-8m3/kg and lower than the local soil which was 40.4×10-8m3/kg. Based on the A-CN-K ternary plot, the dust had a weaker weathering intensity than the local soil, loess-paleosol sequences, and red clay. This indicated that the dust was not a re-deposited loess. Furthermore, according to the discriminating analysis using ratios of Al2O3/TiO2, Fe2O3/TiO2, and Fe2O3/Al2O3, the source for the dust was traced from the deserts of south Mongolia, Tengger, Gulban Tungut, and Taklimakan. The two primary factors transporting the dust were the Mongolia Cyclone and westerlies. The dust was blown into the atmosphere, and transported by the atmospheric circulation from west to east and/or from northwest to southeast, which was accompanied also by a cold front cyclone moving southeast towards the study area. The origin, transportation, and deposition process of the dust deposition in this study provides further evidence about the origin of the loess and its likely role in soil development in Shenyang, northeastern China.