Characteristics of soil particles in the Xiaohulishan deposit, Inner Mongolia, China

Abstract

In this paper, we used transmission electron microscopy (TEM) to study metal-bearing particles in the Gobi Desert soil of the concealed Xiaohulishan deposit in north-western Inner Mongolia. By analysing the category, size, shape, and chemical composition of metal particles in soil samples, as well as their co-occurrence with soil mineral particles in the surface overburden, we determined the characteristics of the metal particles that are related to mineralization. Along with the geological setting, this information can provide insight into prospecting the concealed ore body based on the surface overburden particles. In addition, studying the association between metal particles and soil mineral particles allows us to summarize the adsorption properties of soil minerals for metal particles, and analysing the metal particles carried by ascending gas helps us determine the mechanism by which metal particles are transported by ascending gas flow in the surface overburden. This paper discusses both the natural metal particles and the soil mineral particles that contain metals. We propose that it is possible to prospect a concealed ore body using the characteristics of surface overburden particles, and we summarize the preferences and behaviour of metal particles (mainly Fe-, Mo-, Cu-, Pb- and Zn-bearing particles) adsorbed by soil minerals such as Ca sulphates, silicates, carbonate minerals, and clay minerals. This knowledge is significant because it can help explain the migration mechanisms of metal particles in the soil-covered areas of the Gobi Desert. These findings will also help to explore concealed deposits by facilitating the use of elemental concentrations, as well as the characteristics of metal particles carried by ascending gas flow.