Abstract Central Ireland contains an extensive carbonate succession of Courceyan-Brigantian age, deposited in fault-bounded sub-basins across the Irish Midlands. Carbonate sediments host base metal Pb-Zn deposits of mostly pre-Arundian age, with mineralization episodes controlled by syn-rift crustal extension. As the region is highly glaciated, geological structure is not well mapped. Here, it is shown that the mineralization is spatially correlated with a network of ‘Caledonian’ northeast-southwest trending and interconnecting weaker north-northeast-south-southwest and subtle northwest-southeast trending gravity lineaments. Gravity derivative maps are used to demonstrate these relationships and it is shown that the occurrence of the base metal deposits is related to the local magnitude and direction of the derivatives. The continuity of lineaments across the Carboniferous regions into older Palaeozoic terranes, where they usually correlate with mapped faults, indicates strong Caledonian basement control on Variscan tectonic development and related episodes of base metal mineralization. The reactivation of older basement fractures controlled the migration pathways of mineralizing fluids and the spatial distribution of deposits. These methods applied to densely spaced gravity data are a useful tool in understanding basement and basin-fill properties which influence ore genesis.