Preliminary study on classification and investigation of surface substrate

In January 2020, the "General scheme for construction of natural resources survey and monitoring system" was issued by the Ministry of Natural Resources and the concept of the surface substrates layer was proposed. Classification on the surface substrates is a foundation work for carrying out its surveys, and the prerequisites for conducting surface substrates layers survey conclude to clarify the scientific connotation, temporal and spatial distribution characteristics, supporting targets and survey accuracy of surface substrates. In this paper, we fully draw on the classification methods and map expression styles of regional geology, hydrogeology, engineering geology, Quaternary geology, environmental geology, etc., and integrate the material composition, genetic types, landform shapes and grain sizes of rocks, gravel, sand and soil. On the basis of above, the classification of surface substrate is preliminarily divided into four levels, and we also propose the material composition, genetic attributes, and depth range of the surface substrate layers. Finally, the main investigation and mapping directions for future surface substrate layers are pointed out. All these results will provide a basis reference for the unified classification system of surface substrates and national survey conduction.