GESGB London Evening Lecture | The Impacts of Mineralogical Processes on Net-Zero Geological Systems

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Speaker: Dr David McNamara – University of Liverpool

Topic: The Impacts of Mineralogical Processes on Net-Zero Geological Systems

Date: Tuesday 28 October 2025

Timings: 17:30 – Doors open / 18:00-19:00 – Lecture / 19:00-20:00 – Networking drinks

Venue: The Linnean Society of London | Burlington House, Piccadilly, London W1J 0BF
The venue is located 5-minutes’ walk from Green Park and Piccadilly tube stations. The lecture will be held in the Meeting Room on the ground floor.

Networking Drinks: The Clarence – 4 Dover Street, W1S 4LB
Self-funded bar.

The presentation will be available to view via live stream on Zoom.
Login details will be sent to registered attendees one day prior to the event.

The Impacts of Mineralogical Processes on Net-Zero Geological Systems

Dr David McNamara¹, Aisling Scully², Jonathan Alexander¹, Dr Elisabetta Mariani ¹, Dr Joseph Gardner ¹, Dr Heath Bagshaw, Dr Matthew Bilton¹, Anastasia Walker¹, Aaron Lister³, Professor John Wheeler¹, Professor David Prior³

¹University of Liverpool, Liverpool, UK, ²University College Cork, Cork, Ireland, ³University of Otago, Dunedin, New Zealand

The World looks toward several varied geological solutions to reach Net Zero, from geothermal power and heating, to storing CO₂, to using critical raw materials for green technology development. To meet the growing demand for and ensure sustainable use of this diverse range of geological systems requires new and advanced understandings of the geological processes that operate within these Net Zero systems over time. One set of processes that demands scientific advance are mineralogical processes such as mineral nucleation and growth. Mineralisation in Net Zero geological systems can be both beneficial and inhibitive to the long-term success of bringing a system online. For example, many geothermal reservoirs rely on an open, connected fracture network to sustain geothermal fluid flow. Mineralisation within these fractures can close these pathways up reducing the efficiency and output of a geothermal resource over time. Conversely, mineralisation processes resulting from CO₂-rock interactions can result in the permanent capture of that CO₂ in mineral form, thus removing it from the atmosphere. Similarly, critical raw materials (e.g. lithium, cobalt, molybdenum) are concentrated and migrated into various minerals via sequences of fluid-rock interactions over time. Despite the known importance of mineral processes in Net Zero geological systems, we must still address knowledge gaps linked to how minerals nucleate and grow over time, how fast they grow, and what conditions either enhance or inhibit their formation.

Insights into mineralisation processes can be obtained by sampling and examining the crystallography and chemistry of existing mineralisation within a range of potential Net Zero systems. A range of techniques can be brought to bear on characterising the crystallographic and chemical properties of minerals forming within Net Zero geological systems including electron backscatter diffraction, energy dispersive X-Ray spectroscopy, chemical microprobe, cathodoluminescence, transmitted and reflected light microscopy, and may more. By examining such datasets in concert with each other we can begin to identify which mineral nucleation and growth mechanisms are active in different Net Zero geological systems, gain new insights into rate controlling factors of mineral development, and provide new information to help characterise the conditions under which mineralisation occurs.

Here I present data and results that confirm which, mineralisation processes, predominantly for calcite and quartz, are occuring within geothermal reservoirs in New Zealand, Uganda, and the UK, new mineralogical data on geological systems that are potential targets for mineral carbonation in Ireland, UK and on the Atlantic seafloor, and on molybdenum mineralisation in Ireland. Results show that individual systems can host multiple nucleation and growth mechanims for calcite or quartz formation as a function of various controlling factors from fluid chemistry, fluid temrepatures, to substrate surface properties.

The global pursuit of Net Zero necessitates a comprehensive understanding of mineralogical processes within geological systems, from nucleation and growth and more. Through advanced mineral characterization techniques, we can discern the mechanisms driving mineral development in diverse Net Zero contexts. The results of this research to date underscore the complexity of mineralization in Net Zero systems, emphasizing the need for tailored approaches to ensure the sustainability and effectiveness of Net Zero initiatives.

Keywords
Net Zero, mineralization, geothermal, carbonation, nucleation, mineral growth, quartz, calcite

Dr David McNamara
Associate Professor
Head of the Earth Science Research Group at University of Liverpool
Deputy Director of Scanning Electron Microscopy Shared Research Facility

Dr David McNamara is a geologist with a focus on understanding how fluid flows through the Earth’s crust and how that impacts processes from natural resource generation, operation, and sustainability, to the occurrence of geological hazards. He specialises in the application of structural geology, geomechanics, and mineralogy to assist in the development of Net Zero geological solutions from geothermal, to mining, to carbon storage systems, as well as work to understand the interlinked role between structure, stress, and fluid flow for earthquake behaviour. He obtained his undergraduate in geology from Trinity College Dublin, Ireland, and a PhD in microstructural geology from the University of Liverpool, UK. Post-PhD he worked as a researcher and consultant with GNS Science, New Zealand for the Natural Resources Division, specialising in geothermal geology. Since 2016 he has been working as a university academic first as the Head of the Geofluids Research Group at the University of Galway, Ireland, and now in his current roles at the University of Liverpool. He has served on several committees dedicated to Net Zero progress such as the Geological Society of London’s Energy Group, and the Geothermal Advisory Panel to the government of Northern Ireland. He is also passionate about promoting diversity in STEM and have served as the Chair of the University of Galway LGBT+ Staff Network, and as the early career representative on the Council of the Royal Society of New Zealand.