Explaining metal zonation at the Lisheen Zn-Pb deposit, Ireland

Metal zonation is an important feature of low-temperature carbonate-hosted Zn-Pb deposits. Its origin, however, remains poorly understood. In this article, we use the Lisheen deposit in Ireland as a case study to show how thermodynamic modelling can explain these zonation patterns. Based on input data derived from fluid inclusion studies, bulk ore geochemistry and accepted models of ore formation in the Irish Orefield we construct a reaction path model that successfully accounts for the major features of the mineralisation, most importantly the presence of Cu-Ni-As-rich core zones around hydrothermal feeder structures, surrounded by more distal Fe-Zn-Pb-rich mineralisation. The outcomes of this study strongly support current metallogenetic models for Irish-type deposits and have implications for near-deposit exploration.