Abstract - 3D analysis was used to investigate the structural controls of two Irish Zn-Pb deposits, Lisheen and Silvermines. Left-stepping segmented fault arrays were identified as the controlling structural on the geometry of, and fluid flow within, the deposits and the region. Four relay ramps were identified at Lisheen, two intact, one incipiently
breached and one fully breached, while five relay ramps, two intact and three incipiently breached, were identified at Silvermines. The scale at which these ramps form and their associated degree of breaching were found to play an
important role in ore body geometry and localisation. Locally, fluid flow in fully intact relays is focused migrates both vertically and laterally into areas of structural complexity in the hangingwalls of the bounding segmented faults. Smaller scale, fully breached ramps may act as zones of up-fault fluid flow and as points of ingress for
mineralising fluids to enter host lithologies. At the regional scale, the geometry and periodicity of segmented fault arrays can be used to more effectively target mineralisation.
Ultimately, fault segmentation and relay ramp geometries play a key role in the development of Irish Zn-Pb deposits.
Proceedings of the 14th Biennial SGA Meeting, Quebéc City, Canada, 617-620, 2017. ISBN: 978-2-9816898-0-1