Conference Contribution Details
Mandatory Fields
Blake, S., Henry, T., Muller, M.R., Jones, A.G., Moore, J.P., Murray, J., Campanya, J., Vozar, J., Walsh, J., Rath, V.
International Conference on Groundwater in Fractured Rocks
Conference paper
Chaves, Portugal
Oral Presentation
Optional Fields
05-JUN-17
07-JUN-17
A hydrogeological conceptual model of the source, circulation pathways and temporal variation of a low-enthalpy thermal spring in a fractured limestone setting is derived from a multi-disciplinary approach. St. Gormanís Well is a thermal spring in east-central Ireland with a complex and variable temperature profile (maximum of 21.8 įC). Geophysical data from a three-dimensional (3-D) audio-magnetotelluric (AMT) survey are combined with time-lapse hydrogeological data, and a previous hydrochemical analysis (Blake et al. 2016) to investigate the operation of this intriguing hydrothermal system. Hydrochemical analysis and time-lapse measurements suggest that the thermal waters are temporally variable in temperature and discharge, but flow within the fractured limestones of the Carboniferous Dublin Basin at all times. The 3-D electrical resistivity model of the subsurface revealed two prominent structures: 1) a NW-aligned faulted contact between two limestone lithologies; and 2) a dissolutionally-enhanced, N-aligned, fault of probable Cenozoic age. The intersection of these two structures, which has allowed for karstification of the limestone bedrock, has created conduits facilitating the operation of a relatively deep hydrothermal circulation pattern (likely estimated depths between 240 and 1,000 m) within the limestone succession of the Dublin Basin. The results of this study support a hypothesis that the thermal maximum and simultaneous increased discharge observed at St. Gormanís Well each winter is the result of rapid infiltration, heating and re-circulation of meteoric waters within a structurally controlled hydrothermal circulation system.
SFI
Publication Themes
Environment, Marine and Energy