Abstract
Two cross sections of Weissliegend sandstones from the Rudna Mine, containing copper sulphide rhythmic banding, were studied. Analyses were performed using optical polarizing (PLM) and scanning electron (SEM-EDS) microscopy and XRD. Rhythmites have different sulphide compositions and undergone different alterations. In cross section RZA rhythmites are composed of copper sulphides, mainly digenite, and strongly altered to covellite and atacamite by secondary processes. Primary rhythmites were probably formed via reaction between hydrogen sulphide from the overlying shale and copper-bearing solutions in the sandstone. Extensive weathering and mining waters were probably resposible for atacamite formation, although other possibillities are also considered. In cross section RGM rhythmites are composed of Cu–Fe sulphides (bornite and chalcopyrite) and pyrite. This distinct mineralogy may result from a reaction of hydrogen sulphide from the overlying shale with copper- and iron-bearing solutions. Dissolution of pyrite or iron monosulphides present in the sandstone could enrich the solutions in iron. Primary ore mineralization was overlapped by a secondary mineralization of slightly different composition.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call