Banded ZnS from Bleiberg deposits: new data and concepts of formation

摘要

Banded sphalerite can be formed in a number of ways - ⅰ) coalescence of granular ZnS by subsequent infill of intergranular spaces and replacement of carbonates by sphalerite, ⅱ) precipitation of ZnS and Zn(S, Cl) fibers directly from the solution and their arrangement as parallel needles forming band, ⅲ) replacement of banded pyrite and/or banded Fe-oxysulphides by ZnS, and iv) replacement of banded smithsonite-siderite and banded Zn-calcite and Zn-dolomite by banded ZnS. Different way of formation of banded ZnS is evidenced by relicts of precursor Zn and Zn-bearing minerals.