Evidence of metal migration over concealed gold deposit in loess terrain and its prospecting significance

There is a growing demand for sensitive penetrating geochemical techniques for prospecting transported covered terrains. However, it is difficult to determine whether geochemical anomalies are the result of deep-seated orebodies or lateral transportation. It remains unclear how metal elements migrate through the concealed layer to the surface, which has called into question these methods and limited their use. In this study, we used three approaches, including trace element patterns, isotope tracers, and microscopic observations, to provide evidence of metal migration over a concealed Au deposit in loess terrain. The results of the survey strongly suggest that the surface ore-forming elements are most likely derived from deep-seated orebodies in the study area. Metal migration to the surface resulted in the accumulation of metals in the surface media. Based on microscopic observations and discussion, we developed a model reflecting the main migration mechanism of metallic nanoparticle movement concerning ascending geogas and migration processes. Additionally, this study demonstrates that fine-fraction soil could be an effective approach for prospecting concealed deposits in loess terrains. We anticipate that this assay will enhance the confidence in using and developing penetrating geochemical techniques and enable them to play a greater role in mineral exploration. [Display omitted] •Three types of evidence for metal migration through covering layer to the surface are provided.•Nanoparticles from mineralization migrate upward with ascending geogas to the surface.•Fine fraction soil exaction is an effective approach for prospecting deposits in loess terrain.