Georesources Projects

Fluid flow in deep carbonates: Assessing the geothermal potential of carbonate rocks

At a time when zero carbon technologies are urgently needed, assessment of the potential of the subsurface for geothermal heat and energy generation is critical. Major remaining questions concern: Permeability variations through time, effect of open loop and close loop system, ideal geological settings for high yield and long term sustainability. Projects in this research realm are likely to utilize microscopic analysis combined with targeted field work and either flow through experiments or numerical modelling to constrain the evolution of fluid flow in carbonate rocks. In potential projects the student will investigate natural geothermal systems to learn how best to assess the geothermal potential of the subsurface. The focus will be given to carbonate hosted geothermal systems as these represent a high potential for deep geothermal energy both locally and internationally. Results from this research will have direct implications for assessing the geothermal potential of carbonate rocks.

Academic lead – Prof Sandra Piazolo

Dynamics of scaling and corrosion in the natural environment: Investigating the long-term effect of fluid flow and reactions on permeability of rocks through experiments and numerical modelling

This research theme aims to shed light on the long standing problem of how the permeability of a rock changes through time if exposed to long term fluid flow as for example the case in deep geothermal energy technologies. Research will capitalize on the knowledge base and experimental capabilities that are available in both mechanical engineering/materials and geoscience research. The student will have the opportunity to use cutting-edge analytical, experimental and numerical techniques to develop an in-depth, quantitative understanding of permeability dynamics in natural rocks of different geological history (deformed, undeformed, heterogenous, homogeneous). Special interest lies in the timescale and dynamics of permeability evolution. Outcomes promise to be of high impact in both fundamental and applied science.

Academic lead – Prof Sandra Piazolo

Development of Machine Learning techniques to improve assessment of the subsurface for Sustainable Energy Solutions based on legacy geophysical and geological data sets

 

Local authorities such as City Councils need to assess cost-effectively and quickly the suitability of the subsurface for a variety of subsurface low carbon solutions such as thermal storage, heat extraction from mine water, energy storage using e.g. gravity or compressed air etc.. To be able to do this, they have neither the time nor the money to commission major geophysical and geological data acquisition campaigns. This research theme aims to develop a novel way to utilize existing data sets to the fullest. Using machine learning (ML) techniques we will train our system using high resolution geophysical datasets of known geo-assets to develop strategies to augment existing lower resolution geophysical data sets. For example, high resolution datasets from coal measures in the Glasgow region could be used to inform assessment of other coal measure areas in the UK that have lower resolution geophysical and geological datasets.

Academic lead – Dr Phil Livermore

Lithium enrichments under magmatic and hydrothermal conditions: Insights from deposits in the Balkans.

Lithium is an alkaline element that is highly valued globally, with deposits repeatedly called “White-oil”. This is owing to its effective use for the production of batteries, much needed for the vastly growing electric car industry, among many other sectors industry and daily life. The global deposits of lithium are, however, not sufficient to satisfy the societal needs for this metal. Multiple types of deposits (sedimentary, brines, hydrothermal, magmatic) have been found globally and are currently explored mostly in China, Australia and the USA, with no large volume production anywhere in Europe, yet. This project aims to investigate high temperature (pegmatite) veins and/or volcano-sedimentary deposits of lithium (and boron) at key sites across the Balkan Peninsula. The study will aim to uniquely combine the elemental and isotope signatures of key Li-containing minerals and their mineral associations in an attempt to decipher the lithium distribution and the mechanisms of its enrichment under magmatic and hydrothermal conditions. This study may have impact for the future discoveries and potential exploration of lithium from European deposits.

Academic lead – Dr Ivan Savov

Assessing the geothermal potential of abandoned coalfields in the Yorkshire region: a clean source of energy

Flooded mine workings can provide ambient temperature storage while energy generation through geothermally heated mine water can be utilised in district heating schemes to produce clean and renewable heat energy. However, most mine workings are currently abandoned, and not considered as significant in supporting UK’s transition to low-carbon energy solutions. The urban area of Leeds and the Selby mine ~35 km to the east have such legacy mine workings while local authorities and businesses are interested in the potential of their use. Thus, these areas are ideally suited for an in-depth study.
Depending on the students’ interest, research can be directed towards one or a number of research themes:
– estimation of geothermal energy potential of selected areas utilizing available mine records, their associated geological data and archive seismic reflection profiles augmented with targeted geophysical and geological data acquisition. It may also be possible to conduct new geophysical surveys (including seismic refraction and resistivity methods, possibly extending to distributed acoustic sensing) to enrich the interpretation of the site.
– subsequent assessment of the long-term sustainability of the source as well as optimal use of available geothermal energy based on local demand and supply
– investigation of the stability of the mines and open cavities to assessed the risk of possible eventual collapse and consequent ground-surface movements such as the development of sinkholes, micro-earthquakes or groundwater impacts. Geophysical data analysis and experimental physical testing of representative samples at University labs may provide additional data.
The ultimate goal is to provide local authorities with a scientifically well founded set of recommendations.

Academic lead – Dr Chrysothemis Paraskevopoulou

Platinum and Palladium associated with Cu-Au mineralization, Srednogorie metallogenetic zone, Bulgaria

Platinum (Pt) and palladium (Pd) are precious metals from the so-called platinum group elements (PGE= Os, Ir, Ru, Rh, Pd and Pt). These elements are widely used in medicine, electronics and in the production of catalytic converters for the automobile industry. Unfortunately their terrestrial abundances are low to extremely low in almost all commonly exposed crustal rock types. In addition, only limited deposits of these elements have been mined worldwide, making their ores a highly priced commodity. Usually PGEs are extracted from ultramafic (peridotite) complexes, but recent studies of Cu-Au mineralizations worldwide (Canada, USA, Mexico, Mongolia, Philippines, Bulgaria and Greece), reveal that Pt and Pd may also be enriched in hydrothermally altered alkaline volcanic and subvolcanic bodies. However, the usefulness of such deposits for the Pt and Pd extraction has not been systematically evaluated, although sometimes their abundances may reach several parts per million (ppm) or enrichments of up to 4 orders of magnitude.

This project will build on prior studies of the geology and Cu-Au mineralizations in the Panagurishte region of the Srednogorie metallogenetic zone of Central Bulgaria. This same region supplied Au for the oldest gold jewellery in the world (the “Varna Gold”; 6500 yrs. ago i.e. Copper Age) and also the famous pre-Roman (Thracian) gold treasures. Here the mineralization is hosted by calc-alkaline volcanic and subvolcanic bodies representing the edifices of Cretaceous (~92 M.yrs) intra-oceanic volcanic arc-backarc pair. Specifically, the project will focus on the Pt and Pd distribution in rocks and ores from the region of the Elatzite porphyry and Chelopech epithermal Cu-Au deposits. The aim will be to better understand the mineral associations and the conditions that enhance the PGE enrichements (incl. effects of redox state, alkalinity and Cl content of the hydrothermal fluids).

Academic lead – Dr Rob Chapman

From geoscience to sustainable energy use: investigating geothermal potential in Yorkshire

Geothermal energy is an exciting and bountiful sub-surface source of clean energy, currently still largely untapped across the UK. The structure and geological story of sub-surface Yorkshire presents many geothermal opportunities: from deep thermal energy extraction from underlying granite systems through to heat storage in extensive networks of disused mine across the region. This, combined with the availability of an extensive array of surface and subsurface data from across the region, makes Yorkshire an exciting place to investigate the potential for future geothermal sites.

This project will look to assess the geothermal potential of a segment of the sub-surface located in the Ryedale region of the Askrigg Block (Waters et al, 2020). You will use an array of existing available data, including seismic and borehole geochemical and geophysical data, to develop a conceptual model of the subsurface geothermal system (Cumming, 2009). This will include modelling key controlling structures, assessing potential influence of local and regional stress systems and, with incorporation of all available geophysical data, an assessment of likely thermal conduction, potential heat flow paths and hydrothermal potential (Jolie et al,. 2015). Using the conceptual model, you will determine likely geothermal output potential of this system including temperature and flow rates. Finally, using this data you will develop a plan for potential routes of sustainable use of the energy resource within the region.

Your work will help establish an improved understanding of the geothermal potential in Yorkshire and be part of a wider project to map the region and develop a long term plan for harnessing geothermal energy as part of the UK’s energy transition to efficient, long-term and environmentally friendly energy.

Academic lead – Dr Emma Bramham

Understanding the volcanic heart beneath Ethiopia’s newest geothermal power plant with passive seismic imaging

The Corbetti caldera in the Main Ethiopian Rift (MER) is planned to become the site of Ethiopia’s second and largest geothermal power plant, potentially producing > 1 GW of zero-carbon electricity . Like most ‘high-enthalpy’ geothermal sites, the source of heat is magma injected into the crust, and the heat is transported to the surface along fractures via water-rich fluids. When exploiting such a system, it is critically important to understand the distribution of heat sources and pathways, but there remain significant sources of uncertainty. Reducing uncertainty and quantifying risk in developing geothermal resources is likewise critical. In this project, you will use seismic data to help improve our understanding of the processes at play beneath Corbetti and better image its interior.

Together with your advisors, you will use existing seismic recordings of microearthquakes and make new measurements of surface wave velocities on a network of stations at the caldera. You will then invert these data using new probabilistic methods (Zhang et al., 2020) to reveal the velocity structure of Corbetti, which importantly will include error bounds. You will then integrate this new model with existing geochemical and geophysical models (e.g., Gíslason et al., 2015; Lloyd et al., 2018) to better understand the processes occurring at this volcano, and better constrain the source and pathways for heated fluids. Your work will also help understand other systems in the MER and the structure of volcanoes in general.

References:
Gíslason, G., Eysteinsson, H., Björnsson, G., Harðardóttir, V., 2015. Results of Surface Exploration in the Corbetti Geothermal Area, Ethiopia, in: Proceedings, World Geothermal Congress, p. 10.
Lloyd, R., Biggs, J., Wilks, M., Nowacki, A., Kendall, J.-M., Ayele, A., Lewi, E., Eysteinsson, H., 2018. Evidence for cross rift structural controls on deformation and seismicity at a continental rift caldera. Earth and Planetary Science Letters 487, 190–200. https://doi.org/10.1016/j.epsl.2018.01.037
Zhang, X., Roy, C., Curtis, A., Nowacki, A., Baptie, B., 2020. Imaging the subsurface using induced seismicity and ambient noise: 3D Tomographic Monte Carlo joint inversion of earthquake body wave travel times and surface wave dispersion. Geophysical Journal International 222, 1639–1655. https://doi.org/10.1093/gji/ggaa230

Academic lead – Dr Andy Nowacki