Understanding hydrothermal circulation patterns at a low-enthalpy thermal spring using audio-magnetotelluric data: A case study from Ireland

Blake, Sarah; Henry, Tiernan; Müller, Mark; Jones, Alan G.; Moore, John P.; Murray, John; Campanyà, Joan; Vozár, J.; Walsh, John J.; Rath, Volker

doi:10.1016/j.jappgeo.2016.06.007

Cited by 20 publications

(14 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of low-enthalpy thermal springs were investigated using a multidisciplinary approach, integrating geophysical surveys, time-lapse measurements of hydrogeological parameters, and detailed hydrochemical analysis, with the aims of (1) identifying the source aquifer(s) for the thermal groundwater, (2) characterising the circulatory systems, and (3) assessing the potential for the existence of deeper, higher temperature, circulation patterns for future geothermal exploitation. Two publications have been produced already from this project; Blake et al (2016a) present the results of a hydrochemical analysis of a set of Irish thermal springs, and Blake et al (2016b) describe a geophysical survey at one of This article is part of the topical collection "Progress in fractured-rock hydrogeology". the springs (Kilbrook spring, Co. Kildare).…”

Section: Introductionmentioning

confidence: 99%

“…This paper presents a three-dimensional(3D) electrical resistivity model from an audio-magnetotelluric(AMT) survey at St. Gorman's Well. The AMT method is a passive electromagnetic geophysical technique that is widely used for exploring geothermal resources (e.g., Arango et al 2009;Barcelona et al 2013;Piña-Varas et al 2014;Zhang et al 2015;Blake et al 2016b) and hydrogeological targets (e.g., Falgàs et al 2011;Kalscheuer et al 2015) due to its ability to detect lowresistivity, water-bearing rocks in the subsurface. The depth of penetration can be several hundred metres and even greater than a kilometre below the surface, depending on the resistivity of the bedrock.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterising thermal water circulation in fractured bedrock using a multidisciplinary approach: a case study of St. Gorman’s Well, Ireland

Blake

Henry

Moore³

et al. 2021

Hydrogeol J

Self Cite

View full text Add to dashboard Cite

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 multidisciplinary approach. St. Gorman’s Well is a thermal spring in east-central Ireland with a complex and variable temperature profile (maximum of 21.8 °C). Geophysical data from a three-dimensional(3D)audio-magnetotelluric(AMT) survey are combined with time-lapse hydrogeological data and information from a previously published hydrochemical analysis to investigate the operation of this intriguing hydrothermal system. Hydrochemical analysis and time-lapse measurements suggest that the thermal waters flow within the fractured limestones of the Carboniferous Dublin Basin at all times but display variability in discharge and temperature. The 3D 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 relatively deep hydrothermal circulation (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 maximum temperature and simultaneous increased discharge observed at St. Gorman’s Well each winter is the result of rapid infiltration, heating and recirculation of meteoric waters within a structurally controlled hydrothermal circulation system.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterising thermal water circulation in fractured bedrock using a multidisciplinary approach: a case study of St. Gorman’s Well, Ireland

Blake

Henry

Moore³

et al. 2021

Hydrogeol J

Self Cite

View full text Add to dashboard Cite

show abstract

“…Geothermal energy as a clean and renewable resource can be used for electricity production or direct heating purposes (Olasolo et al, 2016), and geophysics has played a key role in the description of geothermal systems and estimation of their potential for energy utilization (e.g., Domra Kana et al, 2015). Within the framework of Ireland's IRETHERM project (IREland's geoTHERMal potential), geophysical and geological studies were carried out to develop an understanding of Ireland's low enthalpy geothermal energy potential through joint-inversion/integrated modelling of new and existing data (Jones et al, 2015;Blake et al, 2016). IRETHERM comprises three broad geothermal target types,…”

Section: Introductionmentioning

confidence: 99%

A geothermal aquifer in the dilation zones on the southern margin of the Dublin Basin

Vozár

Jones

Campanyà

et al. 2019

Geophysical Journal International

Self Cite

View full text Add to dashboard Cite

SUMMARY We present modelling of the geophysical data from the Newcastle area, west of Dublin, Ireland within the framework of the IRETHERM project. IRETHERM's overarching objective was to facilitate a more thorough strategic understanding of Ireland's geothermal energy potential through integrated modelling of new and existing geophysical, geochemical and geological data. The Newcastle area, one of the target localities, is situated at the southern margin of the Dublin Basin, close to the largest conurbation on the island of Ireland in the City of Dublin and surrounds. As part of IRETHERM, magnetotelluric (MT) soundings were carried out in the highly urbanized Dublin suburb in 2011 and 2012, and a description of MT data acquisition, processing methods, multidimensional geoelectrical models and porosity modelling with other geophysical data are presented. The MT time-series were heavily noise-contaminated and distorted due to electromagnetic noise from nearby industry and Dublin City tram/railway systems. Time-series processing was performed using several modern robust codes to obtain reasonably reliable and interpretable MT impedance and geomagnetic transfer function ‘tipper’ estimates at most of the survey locations. The most ‘quiet’ 3-hr subsets of data during the night time, when the DC ‘LUAS’ tram system was not operating, were used in multisite and multivariate processing. The final 2-D models underwent examination using a stability technique, and the final two 2-D profiles, with reliability estimations expressed through conductance and resistivity, were derived. In the final stage of this study, 3-D modelling of all MT data in the Newcastle area was also undertaken. Comparison of the MT models and their interpretation with existing seismic profiles in the area reveals that the Blackrock–Newcastle Fault (BNF) zone is visible in the models as a conductive feature down to depths of 4 km. The investigated area below Newcastle can be divided into two domains of different depths, formed as depth zones. The first zone, from the surface down to 1–2 km, is dominated by NE–SW oriented conductors connected with shallow faults or folds probably filled with less saline waters. The conductors are also crossing the surface trace of the BNF. The second depth domain can be identified from depths of 2–4 km, where structures are oriented along the BNF and the observed conductivity is lower. The deeper conductive layers are interpreted as geothermal-fluid-bearing rocks. Porosity and permeability estimations from the lithological borehole logs indicate the geothermal potential of the bedrock, to deliver warm water to the surface. The fluid permeability estimation, based on Archie's law for porous structures and synthetic studies of fractured zones, suggests a permeability in the range 100 mD–100 D in the study area, which is prospective for geothermal energy exploitation.

show abstract

“…EM geophysical methods are broadly used to image the electrical resistivity distribution of the subsurface at several depths of penetration, from a few tens of meters to hundreds of kilometers, and for different academic or commercial purposes (Berdichevski & Dmitriev, ; Chave et al, ). With dense station coverage, EM passive geophysical methods can unravel shallow structures providing valuable information, particularly when integrated with additional data sets (Blake et al, ; Falgàs et al, ; Gabàs et al, ; García‐Yeguas et al, ; Ogaya et al, ). An old exploration well (Doonbeg‐1; Figure a) in the Clare Basin, dating from 1962, provides important constraints on the main lithologies and the petrophysical properties (including electrical resistivity) of the rocks in the northwestern part of the study area.…”

Section: Introductionmentioning

confidence: 99%

Subsurface Characterization of the Pennsylvanian Clare Basin, Western Ireland, by Means of Joint Interpretation of Electromagnetic Geophysical Data and Well‐Log Data

et al. 2019

Self Cite

View full text Add to dashboard Cite

The integration of passive electromagnetic geophysical data and well-log data for basin characterization and interpretation has been investigated in the Clare Basin, western Ireland. The Clare Basin is overmature and has a clear contrast in electrical resistivity between the Clare Shale Formation, a widespread organic rich shale unit, and the surrounding stratigraphy. The electrical resistivity distribution beneath the Clare Basin was determined by means of three-dimensional (3-D) joint inversion of three distinct and differently sensitive electromagnetic parameters: (1) the MT impedance tensor (Z), (2) the geomagnetic transfer function (T), and (3) the interstation horizontal magnetic transfer function (H). Well-log data from a local exploration well, Doonbeg-1, were analyzed by means of multivariate statistical methods identifying three groups with distinct resistivity values. The groups were propagated along the basin using the 3-D electrical resistivity model, showing those regions in the basin with significant organic content at high maturity stage. The lack of continuity of these regions supports the hypothesis of advective fluid heating as the cause of the high maturity levels. The results also help to define the geometry of the basin at depth and have identified an area within the basin, near the Loop Head, where organic-rich clay/shale is either poorly developed, and/or the organic matter is less mature and less conductive. Finally, the potential of the basin for both CO 2 storage and geothermal energy was considered, supporting the use of the Clare Basin as a potential site for geothermal energy but not for the storage of CO 2 .

show abstract

Understanding hydrothermal circulation patterns at a low-enthalpy thermal spring using audio-magnetotelluric data: A case study from Ireland

Cited by 20 publications

References 36 publications

Characterising thermal water circulation in fractured bedrock using a multidisciplinary approach: a case study of St. Gorman’s Well, Ireland

Characterising thermal water circulation in fractured bedrock using a multidisciplinary approach: a case study of St. Gorman’s Well, Ireland

A geothermal aquifer in the dilation zones on the southern margin of the Dublin Basin

Subsurface Characterization of the Pennsylvanian Clare Basin, Western Ireland, by Means of Joint Interpretation of Electromagnetic Geophysical Data and Well‐Log Data

Contact Info

Product

Resources

About