Abstract - Detailed digital mapping of the Tellus aero-magnetic data set has revealed the extent and
timing of igneous activity in the north of Ireland during the Palaeogene period (c.66–23
million years). These data have provided a unique opportunity to constrain the geometry,
scale and development of similarly aged faults in the region. Recognition and analysis
of these structures has broadened the understanding of Cenozoic tectonics of Britain
and Ireland, with potential implications for fluid flow in hydrocarbon and groundwater
reservoirs.
The Tellus data set has allowed detailed structural mapping and analysis to be performed
on a regional scale across the north of Ireland. Analysis of the aero-magnetic data has
defined five generations of Palaeocene dyke swarms, which, with central igneous complexes
and flood basalts, have been used to constrain kilometre-scale displacements on NE-trending
sinistral and NNW-trending dextral structures, usually accommodated along
pre-existing Carboniferous normal faults and newly formed faults respectively. The results
of this analysis suggest a tectonic setting during the Cenozoic in which pulsed Iceland
plume-related extension periodically overwhelmed broadly north–south Alpine-attributed
compression. These Cenozoic faults sometimes form conductive pathways for subsurface
flow, both onshore and offshore of Ireland, with potential implications for hydrocarbon
and groundwater exploration and resource management.
In: Unearthed: Impacts of the Tellus Surveys of the North of Ireland. (Edited by Young, M.E.). Royal Irish Academy, Dublin, 180-189, 2016. DOI:10.3318/978-1-908996-88-6.ch14.