Extraction of large-scale geological anomalies and positioning regularities of rich deposits: A case study of the Minle sedimentary manganese deposit, Hunan, China

Abstract

In the exploration of sedimentary manganese deposits, prospecting models with large-scale ore-generating geological anomalies are required to satisfy productive demands. This study presents a novel approach combining theories of sedimentary basin analysis with techniques of quantitative analysis of mineral resources for extracting large-scale geological anomalies based on variations of intra-manganese-basin tectonic and sedimentary environments. For this purpose, the Minle sedimentary manganese deposit in Hunan province, China, was taken as a case study. First, the stratigraphic and lithological characteristics were analyzed to divide the region on the scales of manganese basins and mining areas. Subsequently, suitable paleogeographic features were selected as ore-generating geological anomalies and analyzed for three-dimensional quantitative evaluation of mineral resources. Finally, the thicknesses and grades of ore bodies were quantitatively analyzed to summarize the positioning regularities of rich ores. Pre-mineralization tectonic and sedimentary environments were found to be closely related to the distribution of rich ores. Areas suitable for the formation of rich ores were found to be those that feature coarse clastic sedimentation at the edge of the barrier-tidal flat-lagoon system and experienced a shift in the stable transitional environment from the barrier-tidal flat-lagoon to the bay before mineralization. Large-scale sedimentary features, fault activities, structural styles, and evidence of multiple mineralization mechanisms should also be taken into account in the selection of ore-generating geological anomalies.