Classification scheme for soil-forming parent materials based on geological formations: A case study of Yanbian Korean Autonomous Prefecture, Jilin Province

The scientific classification of soil-forming parent materials provides an important reference for understanding the regional geochemical dispersion and enrichment patterns of elements in soils. Taking the Yanbian Korean Autonomous Prefecture in eastern Changbai Mountain as a case study, this paper proposes a classification scheme for parent materials based on "formation age + rock type + transport pattern". The parent materials in the prefecture are classified into 14 types, including Quaternary alluvial-diluvial deposits, Quaternary mafic volcanic residual-eluvial deposits, Quaternary alkaline volcanic residual-eluvial deposits, Neogene-Paleogene sandstone residual-eluvial deposits etc. The study indicates that the physical and chemical properties of the parent materials and soils in Yanbian are governed by the geological formation units. Soil types varying on the same parent material share similar geochemical characteristics, whereas the same soil type derived from different parent materials displays significant geochemical differences. The classification scheme based on geological formations can effectively reflect the differences in parent materials associated with varying tectonic and diagenetic settings, and meanwhile capture the intrinsic relationship between parent materials and their derived soils.