Structurally controlled fluid flow pathways in the Irish Zn-Pb ore field: Insights from metal distributions at the Lisheen and Silvermines deposits



Torremans K., Kyne R., Doyle R., Güven, J. & Walsh, J.,
Irish Centre for Research in Applied Geosciences (iCRAG) & Fault Analysis Group, School of Earth Sciences, University College Dublin, Dublin, Ireland.

Abstract - The world-class Irish Zn-Pb(-Ag) deposits comprise one of the major metallogenic provinces in the world. The location of these orebodies is structurally controlled, but it is not well understood exactly how fluids migrated from source to sink. This study, therefore, investigates metal distribution patterns at the Silvermines and Lisheen deposits to gain insights into these fluid pathways and the structural controls on mineralisation. Distinct points along segmented normal faults are seen to serve as feeders to individual orebodies. These feeders are characterised by highly localised and elevated Ag, Cu, Ni and As concentrations as well as low Zn/Pb ratios which increase away from these feeders. Metal distributions are initially controlled by major and minor normal faults, and affected by later oblique-slip dextral faults and strike-slip faults. High tonnage areas without typical feeder signals are interpreted to be structural trap sites which are distal to fault-controlled feeder points. This study highlights the importance of a well-connected plumbing system for metal-bearing fluids to reach their basinal traps.

Proceedings of the 14th Biennial SGA Meeting, Quebéc City, Canada, 641-644, 2017. ISBN: 978-2-9816898-0-1