Mineral magnetism identifies the presence of Pyrrhotite in the Navan Zn-Pb deposit, Ireland: implications for low temperature Pyrite to Pyrrhotite reduction, timing of mineralization and future exploration strategies

Presented here are the preliminary results of a pilot study from the Navan Zn-Pb deposit utilising the first example of Superconductive Quantum Interference (SQUID) magnetic microscopy in relation to ore deposits. Using this method of microscale, highresolution magnetic mapping we have identified the pervasive presence of microscopic ferromagnetic pyrrhotite. A previous palaeomagnetic age based on a limited reference frame from N. America by Symons et al. (2002) suggested an epigenetic origin for Navan. We have compiled a new Apparent Polar Wander (APW) path for Scotland that is better constrained for comparison to Navan, to which the Symons et al. (2002) study does not hold true. The identification of pyrrhotite in the ore assemblage holds promise to aid future investigations into the geochemistry of the Irish ore systematics. In addition, our employment of handheld magnetic susceptibility tests on drillcore has defined orders of magnitude differences between samples of economic grade and those of little to no mineralization, this can be developed in the near-mine environment as a novel, cost-effective and low impact method of vectoring towards ore.