Distinguished Lecturer Programme 2021–22

The Society’s Distinguished Lecturers for 2021–22 have been selected. They are Sophie Nixon (U. Manchester) and Hannah Hughes (U. Exeter).

Contact the Society if you would like your Department to host one (or both!) of these lecturers during the coming academic year.  (Application form here)

Dr Hannah Hughes

Lecture A: Going platinum: PGE and chalcophile elements from the mantle to mineral deposits

Metals such as cobalt and the platinum-group elements (PGE) are essential to the development of sustainable technology – from batteries and fuel cells, to resistors in electronics and even in the production of 5G infrastructure. These metals are also classified as critical raw materials due to concerns over security of supply, as they are produced from only a handful of deposits in a few countries. Many of these elements, including platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), cobalt (Co), nickel (Ni), copper (Cu) and gold (Au) have an affinity for sulphur (they are chalcophile) and therefore the most fertile source of these elements comes from the Earth’s core and mantle. In the mantle, these important metals are largely hosted at trace concentrations by base metal sulphides (BMS) and in percentage concentrations in tiny platinum-group minerals (PGM). To be mineralised and concentrated into ore deposits, we must consider how to mobilise these minerals and their precious metal cargo into the Earth’s crust. During partial melting of the mantle, sulphides release a portion of their metal budget into the magma generated, but it remains difficult to fully quantify this process given the diversity of sulphide compositions, let alone understand how PGM become mobilised. And yet, identifying how metals are mobilised out of the mantle into the crust may have some big implications for the fertility of magma, including exotic low degree partial melts such as carbonatites, lamprophyres and kimberlites, and with it some important consequences for mineral exploration. This talk will discuss a range of topics, from the uses and economics of the PGE and other chalcophile critical elements, to metallogenesis and how these metals end up in ore deposits.

Lecture B: Rocks that go bang! Applied mineralogy used in engineering solutions for gases in underground mines

Gases generated from rocks may be present as vapour bubbles in fluid inclusions, gas molecules adsorbed onto mineral surfaces, or accumulated within fractures, voids and pore spaces. Gases may also be produced by a number of mechanisms – biogenically (by microbial processes) or abiogenically (by mineral alteration and reaction). Many underground mines are prone to gas outbursts and explosions; at a minimum, these cause damage to mines, but frequently this can result in injuries and even deaths. For example, methane is a recognized hazard in gold and platinum mines as well as coal mines in South Africa. Gases and volatiles present in some lithologies are sensitive to physical changes of the host rock, such as excavation that causes depressurisation of the surrounding rock mass. This can cause a release of gas and is an important consequence of any mining or underground development. In cases of outburst, the release of gas may be very sudden and we need to understand the sources and pathways of gases to help make mines safer. This talk will introduce how mineralogy may be used to understand what gases might be present in an underground mine, where gas may be located within a rock mass, how gas is produced and trapped, and how all of this might affect the likelihood of an explosive event. See how applied mineralogy, petrology, fluid inclusions, gas chromatography and in situ gas analyses can be applied to identify the causes of an outburst, and how we can use these data as part of a toolset for forecasting the risk of rocks going bang!  

Dr Sophie Nixon

Lecture C: The deep biosphere: What lies beneath and why we should care

The deep subsurface harbours the unseen majority of microbial diversity of Earth, and a significant proportion of the planet’s biomass. Understanding how life operates in these extreme environments highlights the roles these microbes play in biogeochemical cycles of global significance, such as the carbon cycle. Such knowledge also helps to define the limits to life on Earth. However, until recently little was known about the diversity and function of microbial life in the deep biosphere. With the recent advent of affordable sequencing technologies and ever sophisticated tools to unpick the genetic code, we now know that the deep subsurface harbours an active and highly diverse biosphere.  In this talk I will present data from subsurface environments that highlight the diversity of deep life, and its contributions to biogeochemical cycling. Examples will include evidence for an active carbon- and sulfur-cycling microbial community in a deep borehole in Greenland, a novel genus of bacteria recovered from a 2.5 km deep shale gas well, and a glimpse of the microbial life deep beneath our feet in the North of England. With these examples I will demonstrate the power of cutting-edge genomic tools for uncovering the ‘rules of life’ in the subsurface, and highlight the significant potential to put subsurface microorganisms to work for the good of the environment and society.

Lecture D: The microbiology of the engineered subsurface: Finding innovative solutions towards a sustainable future

Society relies heavily on the subsurface for waste storage and resource recovery, and this reliance will only increase as we look to the subsurface to store CO2 emissions and sustainable fuel. However, little consideration is given to the microbial life residing within the subsurface until microbial processes become problematic for engineering. For example, a long-known and costly microbial problem is the production of hydrogen sulfide during oil and gas extraction, which causes corrosion to extraction infrastructure, souring of the hydrocarbon, and poses a risk to rig workers and the environment alike. We now know that microbial communities in the subsurface are highly diverse and often active. As such, any engineering intervention will impact on these communities, and in turn these microorganisms are likely to impact on our engineering efforts, for good or for bad. In this talk I will present recent and ongoing research into the microbiology of shale gas extraction activities in the US and UK to highlight problematic processes uncovered through lab-based experiments and genomic analyses of field samples. I will demonstrate how uncovering microbial processes in an engineered environment could inform best practices for industry, as well as yielding fundamental insights into microbial survival and function in extreme subsurface habitats. Looking to more sustainable uses of the subsurface, I will introduce my next major research venture – understanding the microbiology of deep geological CO2 storage – with a particular emphasis on how we can look to subsurface microbiology to develop novel biotechnological approaches to help achieve our ambitious NetZero goals by 2050.