Geological Survey of Ireland

Sedimentary basins in Northern Ireland are increasingly recognised as promising targets for low- to medium-temperature geothermal energy, yet their subsurface architecture and reservoir properties remain poorly constrained. The Lough Neagh Basin exhibits elevated geothermal gradients relative to other regions of Ireland and represents a low-enthalpy, sedimentary-basin geothermal system. The basin is known to contain sedimentary rocks ranging from at least Permian to Upper Cretaceous in age, overlain by thick Paleogene basalts. Within this system, the electrically conductive Triassic Sherwood Sandstone Group is considered the principal geothermal reservoir, although deeper Permian sandstone units may also have reservoir potential.In this study, we assess the geothermal potential of the Lough Neagh Basin using a broadband magnetotelluric (MT) dataset comprising more than 250 MT stations, including 118 newly acquired stations as part of the GEMINI (Geothermal Energy Momentum on the Island of Ireland) project. MT data were processed to derive impedance tensors and vertical magnetic transfer functions, followed by phase tensor and induction arrow analyses to characterise dimensionality and lateral resistivity variations. Three-dimensional (3-D) MT inversion was then applied to recover the subsurface resistivity structure.The resulting 3-D resistivity structure reveals laterally extensive low-resistivity zones with a spatially variable upper boundary, typically initiating at depths of ~0.7–1.0 km and extending to ~2–2.5 km beneath a high-resistivity basalt sequence. These zones are interpreted as the Triassic Mercia Mudstone Group–Sherwood Sandstone Group succession with variable thickness, consistent with borehole constraints and regional geological understanding. While MT primarily constrains the geometry of this conductive package, integration with petrophysical measurements from selected rock samples and other geophysical datasets (i.e., gravity and passive seismics) aids discrimination between mudstone- and sandstone-dominated intervals, enabling first-order estimates of reservoir geometry and associated heat capacity within the Lough Neagh Basin geothermal system.

Abstract. The Permo-Triassic Sherwood Sandstone Group is an important aquifer with potential for both shallow and deep geothermal energy use in the UK. This study investigates the hydrogeological properties of the shallow buried Sherwood Sandstone Group in Northern Ireland, with a focus on its porosity, using borehole nuclear magnetic resonance (BNMR) and petrophysical models (Archie and Waxman-Smits). BNMR and downhole geophysical logging (resistivity, EC, temperature and natural gamma) were carried out on three boreholes drilled into the lower Sherwood Sandstone Group aquifer at depths of about 100 m on Queen's University Belfast campus. The results showed that the porosity calculated from BNMR and the Waxman-Smits model are comparable, demonstrating the relationship between BNMR and petrophysical-derived porosity. The average porosity of the Sherwood Sandstone Group at this location ranges between 14.9 % and 17.6 %, with maximum values ranging between 33.7 % and 40.4 %. However, the results from the Archie model are significantly larger than those of BNRM, confirming its unsuitability for lithologies containing clays, even in small amounts. This study confirms storage capacities in the lower Sherwood Sandstone Group that make it suitable for ATES systems.

Coastal change assessments have significant socioeconomic, environmental, and infrastructure implications due to the extensive impacts of climate change, such as rising sea levels, the increasing frequency and intensity of storms, as well as the consequences of human intervention.  Satellite products have been used to monitor the coast at relatively high resolution (30 m) since the 1970s through the Landsat program. However, the arrival of the EU Copernicus/Sentinels in 2014 introduced a marked increase in coastal applications thanks to the improved spatial and temporal resolutions. The research presented in this study explores the derivation of waterlines from Sentinel 2 imagery and the creation of a novel holistic approach to a validation framework. Specifically, this study aims to: a) explore the inherent waterline errors against reference datasets and begin to establish the overall uncertainty in deriving waterlines from optical satellite imagery; and b) assess the potential of these results and their suitability for coastal change applications. The results indicate an average positional error of approximately 4 meters for Sentinel images in coastal regions by evaluating the Sentinel-2 satellite images with distinct features visible in aerial orthophotography. Subsequently, the horizontal and vertical inaccuracies of the satellite-derived waterlines (SDWL) were further determined by using a GNSS line as a reference dataset. The horizontal assessment was conducted by calculating the average distance between the SDWLs and the GNSS reference lines across eighteen Sentinel-2 images corresponding to the years 2021, 2022, 2023 and 2024. These were analysed, showing a median displacement of 15 meters, and indicating an offshore trend for the satellite-derived waterlines. The vertical assessment, or height error, was computed by comparing the average height of SDWLs (as determined by the average tide gauge heights) with the reference dataset height (as measured by GNSS), resulting in a mean absolute error of 6 cm. The vertical results indicate that the SDWLs’ heights, as measured by the local tide gauges, align well with in situ local height measurements. The results of this study will aid in identifying temporal and spatial scales and resolutions at which Earth Observation products are suitable for coastal management. The initial stages of a validation framework are presented to assess the quality and applicability of satellite-derived waterlines for coastal change monitoring based on specific user requirements. Identifying the sources of error and improving uncertainty models for satellite-derived products enables better decision-making in coastal management. These analyses will demonstrate whether the outcomes remain consistent among satellite images or change according to local environmental conditions. Increasing end-user confidence in the rates of change obtained from available satellite products can provide crucial information in study areas, and at space-time resolutions previously unattainable.

The end-Triassic mass extinction (ETME) and global climatic perturbation coincide with the onset of Central Atlantic Magmatic Province (CAMP) emplacement. The associated perturbation to the global carbon cycle is reflected by a ~ 3 – 6 ‰ negative carbon isotope excursion (CIE) coinciding with the ETME. The magnitude and duration of the negative CIE are however poorly constrained. Furthermore, the Early Jurassic Hettangian stage, marking the initial recovery phase following the end-Triassic mass extinction, has been the subject of significant debate over its precise timing and duration. Estimated Hettangian stage durations derived from cyclostratigraphic and U-Pb geochronological analyses vary between a ‘short Hettangian’ of 1.8 – 2.5 Myr, and a ‘long Hettangian’ of 3.9 – 4.4 Myr. Poor time constraints for the Triassic–Jurassic interval impact understanding of the timing and rate of biogeochemical cycling, environmental and biological recovery after the end-Triassic mass extinction, and global climatic perturbation.We here conducted carbon isotopic and cyclostratigraphic analysis of the well-preserved, biostratigraphically complete, and expanded Hettangian succession in the Carnduff-2 core of the Larne Basin (Northern Ireland), nearby the Waterloo Bay outcrop. The studied sedimentary succession (~120 m in core) stratigraphically spans the upper Rhaetian (upper Triassic), including the end-Triassic mass extinction, Hettangian, and lower Sinemurian (lower Jurassic), and consists of predominantly mudstone, with varying degrees of limestone and silt throughout the succession. Cyclostratigraphic analyses of elemental and carbonate concentration data show a hierarchy of dominant frequencies, interpreted to reflect long and short eccentricity, obliquity, and precession. These observations suggest a total duration of ~2.2 Myr for the Hettangian Stage with a sedimentation rate of ~ 4.1 cm/kyr, confirming the ‘short-Hettangian’ hypothesis. The negative carbon isotope excursion (CIE) duration, which coincides with the ETME, is estimated at ~290 kyr. The first occurrence of the Jurassic ammonite Psiloceras tillmanni, marking the onset of Hettangian biotic recovery after the ETME across the British Isles, ~320 kyr after the end-Triassic negative CIE, suggesting a prolonged period of biotic demise in response to CAMP induced climatic and environmental upheaval at this time.Key Words: end-Triassic mass extinction, Early Jurassic, Hettangian stage, Milankovitch cycles 

Launched in 2021, the Geoscience for Leaving Certificate Geography Continuing Professional Development Course, run by iCRAG, the Science Foundation Ireland research centre in Applied Geosciences, and Geological Survey Ireland, a division of the Government of Ireland, has entered its third iteration. Addressing the absence of geoscience as a standalone subject in Irish schools, this course introduces post-primary teachers, and therefore their students, to geoscience through the non-compulsory subject of geography. In this course, teachers work in collaboration with geoscience researchers to produce an array of free, readily accessible geoscience resources via the iCRAG and Geological Survey Ireland websites. This addresses the shortage of specialised geoscience material available to Irish geography educators, thus ensuring that students have access to contemporary and accurate geoscience information. Furthermore, the involvement of teachers from a variety of educational contexts guarantees that the resulting lesson plans are versatile and suitable for a broad spectrum of educational settings.In the 2023 iteration of the course, a diverse range of educational resources were developed, including field guides, a 6-week module and lesson plans. These materials integrated seven of the eight recognised active learning intelligences: Linguistic, Logical-mathematical, Visual-spatial, Bodily-kinaesthetic, Interpersonal, Intrapersonal and Naturalistic. With the support of researchers, teachers were able to incorporate essential geoscience skills such as field work, data collection, mapping/GIS, critical thinking and other scientific skills into the curriculum. The lessons were differentiated to meet the varied needs of students, whilst ensuring there was a focus on the Leaving Certificate exam (the final exam of the Irish secondary school system and main gateway to third level). Teachers reported significant benefits from their interactions with geoscientists, appreciating the opportunity to consult with specialists for in-depth inquiries and clarifications. Likewise, it is hoped that students reap the rewards of this educational approach, deepening their understanding of geoscience.Researchers, from iCRAG and Geological Survey Ireland, participating in the program also derived significant benefits, particularly in gaining an understanding of how to distil complex scientific topics for a varied student audience, something that teachers are expert at. The preparation phase for their presentations underscored the importance of balancing technical accuracy with the existing curriculum constraints, an important consideration given the occasional misalignment between current geoscience knowledge and the content of the Leaving Certificate geography syllabus. This exposure to curriculum limitations gives researchers an insight into the public’s perception of science. Additionally, teachers exposed the researchers to a range of student perspectives, such as the diverse reactions to geothermal energy. Also, the observation of differentiated teaching methods, which are not often found in the traditional university lecturing styles, provided invaluable insights into the diversity of educational approaches.The CPD course exemplifies a successful model of collaboration between teachers and geoscientists, enhancing geoscience education while providing mutual benefits. It not only enriches the teaching methodology but also offers researchers a unique perspective on the dissemination of scientific knowledge, thereby bridging the gap between academic research and practical classroom application.

This work describes the application of semantic web standards to data quality governance of data production pipelines in the architectural, engineering, and construction (AEC) domain for Ordnance Survey Ireland (OSi). It illustrates a new approach to data quality governance based on establishing a unified knowledge graph for data quality measurements across a complex, heterogeneous, quality-centric data production pipeline. It provides the first comprehensive formal mappings between semantic models of data quality dimensions defined by the four International Organization for Standardization (ISO) and World Wide Web Consortium (W3C) data quality standards applied by different tools and stakeholders. It provides an approach to uplift rule-based data quality reports into quality metrics suitable for aggregation and end-to-end analysis. Current industrial practice tends towards stove-piped, vendor-specific and domain-dependent tools to process data quality observations however there is a lack of open techniques and methodologies for combining quality measurements derived from different data quality standards to provide end-to-end data quality reporting, root cause analysis or visualisation. This work demonstrated that it is effective to use a knowledge graph and semantic web standards to unify distributed data quality monitoring in an organisation and present the results in an end-to-end data dashboard in a data quality standards-agnostic fashion for the Ordnance Survey Ireland data publishing pipeline.

National and international climate change mitigation plans require a knowledge of peat soil extent across large geographic areas. Peat soils, which play a vital role in carbon storage and climate regulation, have a physical margin where soils change from high to low organic content. Accurate delineation of both national extent of peat soils and peat to mineral soil transition is required for assessing land use and planning effective conservation and carbon loss mitigation strategies. This abstract presents a novel approach for defining both peat soil extent nationally and transition zones between peat and mineral soils at field scale. At a national scale, peat soil maps are created using optical satellite remote sensing or legacy soil/quaternary maps or a combination of both. However, optical remote sensing cannot detect peatlands under landcover such as forest or grassland and legacy maps are often created from sparse in-situ auger data making the accurate delineation of the boundary between peat and mineral soils difficult and cost prohibitive. Airborne radiometric data, which measures natural environmental radiation, has been shown to differentiate between peat and mineral soils due to high attenuation of gamma rays in organic soils. Radiometric data is considered a direct measurement of the subsurface and so is minimally affected by landcover. Additionally, as airborne radiometric data can be acquired in a spatially consistent manner, it has the potential to identify areas of peat soil across the landscape and highlight areas of transition between high and low organic soils. In Ireland, the Tellus survey, acquired by Geological Survey Ireland (GSI) aims to acquire airborne data (including radiometric data), consistently across the country (flight line spacing of 200m) at a resolution of 50 x 50 m. Utilising this national radiometric dataset, a machine learning classification methodology is presented. Data are classified as peat (> 30 % organic material) or non-peat, with 85 % accuracy, is validated using a national soils sampling survey. A confidence value is extracted, once data are classified, which results in the identification peat soils. Several field sites across the midlands of Ireland, which are located at verified transition zones, are then used to show the effectiveness of the classification at identifying transition zones at the field scale. The methodology is robust and can be applied in all areas where these data exist. The results highlight that inclusion of an airborne radiometric dataset in a national climate plan can be used to update national and international carbon inventories of peatlands areas and inform European policy. Understanding the location of these peat to mineral soil transitions is paramount when considering the impact on climate change mitigation strategies such as potential impact of rewetting of peat soils.

Communicating the subsurface is a challenge. Geoscientists are trained to visualise what is underneath them and to see the subsurface in 3D, whereas planners, policy makers and the people impacted by both (i.e., the public) are not. Over many years, Geological Survey Ireland has developed several services in different formats to help pull together information about the subsurface, to present it in an organised manner and to portray it in three dimensions. Underpinned by the organisation’s commitment to open data and re-use of public sector information, these services are: National Geotechnical Borehole Database Geotechnical Viewer 3D models and model viewer Assembled over several decades, the National Geotechnical Borehole Database has expanded with the submission of ground investigations that have been carried out ahead of development projects by the private and public sectors. It acts as a secure, national repository and is a valuable resource for: planning and optimising future ground investigations; understanding the subsurface and urban geology; for helping construct 2D and 3D models. For ease of access, data and reports from the National Geotechnical Borehole Database are published on the Geotechnical Viewer, freely available to all.  The online Geotechnical Viewer displays ground investigations as digitised, georeferenced polygons, with an associated downloadable report in .pdf format. Several thousands of ground investigations projects are presented. With time and technical and software advances, Geological Survey Ireland has produced urban 3D geological models using the National Geotechnical Borehole Database. A primary function of these models is visual communication of the subsurface to geoscientists, professionals from other disciplines, researchers, students and members of the public. Our urban 3D models can assist with: Resource (water and geothermal) mapping; Understanding and characterising urban geology, with potential relevance for basement impact assessment, Sustainable Drainage Systems (SuDS), flooding and, subsurface management; Optimising geotechnical investigation, design and construction; De-risking human activities from impact of our subsurface environment; Investigating impact of human activities on environment around and beneath us, e.g., dewatering; and informing policy, planning, protective and climate adaptation measures. 3D geological models allow everyone to visualise the subsurface and can be used to communicate the geoscience behind policy, thereby making defensible decisions visible. To ensure the 3D models are easily accessible by all, Geological Survey Ireland have a 3D model viewer where no software or zip file downloads are needed. The 3D model viewer has Interactive and Augmented Reality functionality. Recognising the importance of freely available, accessible data for non-geoscientists, Geological Survey Ireland has created and smoothed pathways for stakeholders to access and visualise geological data in urban settings.

Abstract Determination of the physical properties of subsurface geological bodies is essential for georesource management and geotechnical applications. In the absence of direct measurements, this usually passes via geophysical methods such as seismic and ground‐penetrating radar. These require conversion to physical properties, and measurements at different scales to test for consistency. This approach is non‐trivial in geobodies with heterogeneous patterns of properties. Tufa mounds—in‐situ terrestrial carbonate buildups precipitating from geothermal waters—are characterised by high contrasts in facies and petrophysical properties from microscale to macroscale, and are therefore ideally suited to test the ability of non‐invasive geophysical methods to estimate such contrasts, and to develop petrophysical models based on geophysical properties. Here, a laboratory‐based study of a Pleistocene tufa mound in Spain is presented that combines (1) petrography, (2) digital 2D pore network analysis, (3) gas porosity and permeability measurements, (4) acoustic velocity measurements and (5) electromagnetic wave velocity and porosity determination from ground‐penetrating radar, to develop empirical petrophysical models. These results show the consistency of petrophysical properties determined with different methods across various observational scales. Electromagnetically derived porosity positively correlates with gas porosity. Petrophysical properties depend on measurable rock fabric parameters and the degree of cementation, which provide predictive tools for subsurface geobodies. Strongly cemented peloidal‐thrombolitic fabrics with intergranular and intercrystalline pores, and a dominance of small complex pores best transmit acoustic waves. Weak cementation and a significant fraction of large simple pores (framework, vegetation moulds) increase porosity and permeability of shrubby fabrics, while causing lower acoustic velocity. This study demonstrates that ground‐penetrating radar models can be used in combination with direct measurements of physical subsurface properties to capture highly contrasting physical properties associated with different sedimentary facies that would not be achievable with other methods, thus improving the understanding of formational processes.