An exploration on investigation and mapping of ground substrate in Ruyi River Basin, Bashang Plateau, Chengde City

The investigation and mapping of ground substrate is a whole new field of natural resources survey and monitoring system in the current situation, which has not been evolved into a unified guideline on action. In this paper, based on the summarization of the current situation of the Earth’s critical zone theory and ground substrate survey, fully drawing on the investigation methods and map expression styles of regional geology, engineering geology, Quaternary geology, hydrogeology, environmental geology, etc., and taking Ruyi River Basin in Bashang Plateau of Chengde City as the research area, we establish the method of the investigation and mapping of ground substrate based on the theory of the Earth’s critical zone. Based on the field investigation results, the ground substrate in Ruyi River Basin can be divided into nine types as follows: basalt, andesite, tuff, rhyolite, alluvial-proluvial gravel, eluvial-proluvial gravel, aeolian sand, lacustrine silt and marsh silt. The distribution characteristics as well as the investigation and monitoring indicators in different types of ground substrates are also studied. The spatial distribution map of aeolian sand thickness, coupling relationship profile between the ground substrate and the ground covered layer, and ground substrate map are drew. The spatial distribution map of ground substrate thickness can show the spatial distribution characteristics of the thickness of different types of surface substrate layers. The coupling relationship profile of ground substrate and surface covered layer can directly describe the constraint of the profile structural characteristics and physical and chemical properties of ground substrate on the ecological elements of the covered layer. The ground substrate map can systematically reflect the structure, distribution, characteristics and coupling relationship between ground substrate and ground covered layer. The series maps of ground substrate are the reflection of the interaction of multiple cycles in the Earth’s critical zone, such as the rock, the soil, the water, and the organism. The results of this study can provide references for the nationwide investigation and mapping of the ground substrate.