ICRAG Research Collection
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iCRAG’s overarching objectives are: to significantly de-risk Ireland’s offshore and onshore hydrocarbon and mineral resource exploration, thereby increasing exploration activities and also increasing the potential of sourcing a secure supply; to ensure safe and secure groundwater supplies and to address geoscience related ‘quality of environment’ issues; and to engage with citizens and policy makers to explain the nature of resource related industries.
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- PublicationAn Overview of Deep Geothermal Energy and Its Potential on the Island of Ireland(EAGE, 2023-02-01)This paper provides a short overview of geothermal energy, including a discussion on the key geological controls on heat distribution in the subsurface, and on the different types of geothermal resource and their potential uses. We then discuss the island of Ireland as an example of the role that geothermal energy can play in decarbonising the heat sector in a region characterised by relatively low-enthalpy (temperature) resources. Significant shallow geothermal potential exists across the island via the deployment of ground source heat pumps. The geology of onshore Ireland provides relatively limited potential for deep hydrothermal aquifers with primary porosity and permeability. Therefore, deep geothermal exploration on the island is likely to be focused on fractured carbonate reservoirs of Carboniferous age, with recorded groundwater temperatures reaching 38°C at 1 km depth, or on lower permeability petrothermal reservoirs developed as Enhanced or Advanced Geothermal Systems. The exception to this occurs within Mesozoic basins in Northern Ireland where porous and permeable Permo-Triassic sandstones are preserved beneath Paleogene basalts. Geothermal potential also exists in equivalent basins immediately offshore Ireland. For example, Triassic sandstones within the Kish Bank Basin, a few kilometres off the coast of Dublin, have estimated reservoir temperatures of 20–120°C across the basin.
93Scopus© Citations 2 - PublicationUnderstanding Sediment Dynamics at a Shipwreck Site Using CFD Modelling(MDPI, 2022-10-07)Shipwrecks are important cultural heritage sites offshore. In many instances, given their often long-term emplacement on the seafloor, they offer natural laboratories to study complex interactions between human-induced obstacles and seabed dynamics. Such interactions and induced sediment mobility also pose significant threats to offshore engineering infrastructure, such as turbine monopile foundations. Traditional methods can struggle to capture the nuance of these processes, with real-world surveys measuring effects only after installation, and laboratory models suffering from scale-down inaccuracies. Computational fluid dynamics (CFD) modelling offers an effective means of investigating the effects of obstacles on seabed dynamics, and by using shipwrecks as proxies for infrastructure, it can utilize long-term datasets to verify its predictions. In this study, high-resolution temporal bathymetric data were used in, and to verify, CFD modelling to investigate the interactions between hydro- and sediment dynamics at a shipwreck site in a tidally dominated wreck site. From this comparison, simulations of bed shear stress and scalar transport correlate well with known areas of erosion and deposition, serving as a basis for future scour prediction studies and creating effective tools in offshore renewable infrastructure planning and de-risking.
52 - PublicationThe role of antithetic faults in transferring displacement across contractional relay zones on normal faults(Elsevier, 2023-03)Contractional relay zones between pairs of normal faults are sometimes associated with multiple antithetic faults in a geometry similar to that found in Riedel shear zones. Detailed fault displacement profiles of outcrop examples of this geometry demonstrate that the antithetic faults accommodate the transfer of displacement between the synthetic faults that bound the relay zones. The throw on individual antithetic faults, or R′ shears, is typically constant across relay zones while the throw profile on the synthetic faults, or R shears, is stepped; the steps occurring across branchpoints with abutting R’ shears. Transfer of fault displacement occurs by a combination of block rotation and irrotational block translation within the relay zone. As fault throw increases, contractional relay zones are by-passed by the linkage of the synthetic faults, in a manner analogous to the formation of P-shears by the linkage of R shears in classic Riedel shear experiments, but with the original relay zone structure still preserved within the fault zone. With yet further strain bedding may rotate into near-parallelism with the fault surface, with the original geometrical configuration of the relay zone difficult to unravel.
187Scopus© Citations 5 - PublicationBed-parallel slip associated with normal fault systems(Elsevier, 2022-07)Stretching of the Earth's upper crust is commonly accommodated by normal faulting, fault-related folding and/or fracturing such as veins and joints. However, an increasing number of outcrop-scale studies highlight that extension is also accompanied by bed-parallel slip (BPS). The identification of BPS surfaces is, however, challenging due to their localised nature within bedded host rock sequences, the absence of suitable slip markers, and the scale and resolution of both outcrop and seismic reflection data. Here, we present examples of BPS identified within extensional fault systems in sedimentary sequences and outline the nature, magnitude, segmentation, and spatiotemporal distribution of BPS surfaces. These constraints provide a basis for defining the principal structural controls on BPS development and its geometric and kinematic relationship to normal faulting. We conclude that BPS is a common feature within multi-layered host rock sequences, irrespective of their lithological and mechanical properties, and is kinematically associated with a broad range of fault-related deformation, including bed rotations, flexural-slip folding, and both tectonic and gravity-driven sliding. The presence of BPS within normal fault systems can increase the complexity of the host rock volumes and fracture arrays with potential implications on subsurface fluid flow and seismicity.
162Scopus© Citations 7 - PublicationTime-Lapse Monitoring of Moisture Induced Landslide Using Surface Waves at Hollin Hill Landslide Obsevatory(European Association of Geoscientists & Engineers, 2021-09-01)For about fifteen years, the Hollin Hill site has been used as a landslide research site to test different geophysical characterization and monitoring methods, to assess temporal and spatial stability, and the following methods are regularly evaluated on site: ERT resistivity mapping (Chambers et al. 2010, Uhlemann et al. 2017), self-potential methods SP (Chambers et al. 2008), more recently seismic refraction tomography SRT (Whiteley et al. 2020, Uhlemann et al. 2016). The dynamics and ongoing subsurface processes of the Hollin Hill landslide are therefore relatively well described in literature (Whiteley at al. 2019a). Seismic methods based on characterization of P-wave (Vp) and S-waves (Vs) propagation and in particular on Vp /Vs ratio are commonly used in a landslide context (Grandjean et al. 2009, Mainsant et al. 2012). Since mid-2000, methodological improvements have led to increased routine use of dispersion inversion of Vs in hydrological applications (Pasquet et al. 2015; Dangeard et al. 2016) and in geotechnical applications (Donohue et al. 2011, Bergamo et al. 2016). This abstract therefore discusses current geophysical research to monitor seasonal variations using surface waves content (Rayleigh waves) from SRT acquisitions, in the context of moisture induced landslide monitoring, at the Hollin Hill Landslide Observatory.
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