Pyrolusite and Chalcophanite Forming in Qixiashan,Nanjing

Weathering of manganese-bearing carbonate could form chalcophanite. In this paper, the occurrence of Fe (hydro) oxides and Mn-bearing minerals in Qixiashan were identified by XRD and SEM, mainly consisted of goethite, hematite, pyrolusite and chalcophanite. From the microscope investigation, stromatolite-like structure phenomenon is widespread existed, which may be caused by microbial activities. To identify the mineral structure in the Fe-Mn crust, Raman and XPS were used to identify the mineral structure and valence of Fe, Mn and Zn. This work could help us to know the relationship of Fe and Mn during the weathering of manganese-bearing carbonate. And the enrichment of Mn and Zn from the supergene environment could provide a path for the contamination of heavy metals.