The volcano-stratigraphic setting of the Pallas Green Zn-Pb deposit, County Limerick.

Abstract

The Pallas Green deposit located in County Limerick is being actively explored by Glencore Zinc Ireland Ltd. The deposit displays broad similarities with other Waulsortian Limestone hosted deposits in the Irish Orefield in terms of stratigraphical setting, ore-hosting breccia textures and sulphide mineralogy. How-ever, there are a number of important differences, including a close association with igneous rocks, the scale of the ore-hosting breccia bodies, and the apparent absence of significant displacement normal faults control-ling the mineralizing system. The lack of obvious structural control, combined with spatial coincidence with volcanic rocks makes Pallas Green an “Irish-type” deposit with many unique characteristics and new insights into the origins of zinc-lead deposits in the Irish Orefield. This paper endeavours to outline the geological stting, influence of the volcanic activity, alteration and brecciation, and the nature and scale of the mineralizing system at Pallas Green and place the deposit in context and with respect to other “Irish-type” deposits.

Irish-type Zn-Pb deposits in the context of global zinc supply

“…None of the above 5 deposits are associated with contemporaneous igneous rocks, with the exception of minor, thin (1-5 cm) tuff ("green shale") horizons in the underlying Ballysteen and supra Waulsortian Formations. However, more recent discoveries by Xstrata-Minco at Pallas Green (Blaney et al, 2003) and by Teck-Connemara at Stonepark (Redmond, 2010) while broadly similar to other Waulsortian-hosted deposits in terms stratigraphic setting, hydrothermal breccia textures, and sulphide mineralogy, have a spatial and temporal association with igneous rocks (Elliot et al, 2019). However, the relationship between base metal mineralization and Lower Carboniferous magmatism is not well understood.…”