Orthomagmatic Ni-Cu-Au-PGE mineralisation in Ireland and Northern Ireland: A review of historic exploration and future prospectivity

Platinum group elements (PGEs) are essential constituents in established and emerging green technologies, yet European supply is dominated by a small number of very large deposits, necessitating the identification of alternative domestic sources. Most economic mineralisation is associated with orthomagmatic Ni-Cu-Au-PGE systems, where chalcophile elements are concentrated within sulphide minerals in mafic-ultramafic layered intrusions or conduit systems. Irish and Northern Irish centres have been identified among the most prospective European PGE targets and have been subject to exploration since the 1960s, largely focused on Paleogene intrusions. This study reviews the geological framework, exploration history and prospectivity of PGE mineralisation in Ireland and Northern Ireland, synthesising published data and exploration records. Historic exploration has failed to identify deposits of economic scale, likely because mineralisation is highly localised and controlled by magma system architecture, with country rock contacts and fault-controlled dyke geometries influencing sulphide saturation and accumulation. Although Ireland does not host mineralisation comparable in scale to existing world-class deposits, such systems are unlikely to occur anywhere in Europe. In this context, mineralisation of the type proposed in Ireland may represent a realistic model for future European supply, while providing a natural laboratory for understanding tectonomagmatically controlled mineralising processes at local scales.