Lecture meetings are held on the second Thursday of every month from October until May at 7:30 pm in the Gregory Building’s lecture theatre. The lectures usually last about an hour, and are followed by tea/coffee and biscuits, with a chance to chat to members of the society and to look at the publications in the society’s bookshop. The meetings finish at around 9:30 pm.
If you are a non-member interested in our society please accept this invitation to attend.
10th October 2019
Nick Schofield, Aberdeen University
Hydrocarbon exploration in volcanic effected basins
14th November 2019
Peter Ledingham, Geoscience Ltd, Cornwall
The United Downs Deep Geothermal Power project
12th December 2019
Gawen Jenkyn, Leicester University
Green gold? How to get metals out of the ground in a “green” and sustainable way
9th January 2020
John Brown, Arup, Edinburgh
Engineering geology of the Queensferry Crossing
13th February 2020
Amanda Owen, Glasgow University
Understanding the spatial variability of sedimentary deposits
12th March 2020
Professor Andrew Scott, Royal Holloway, University of London
Burning planet: the story of fire through time
9th April 2020
Professor Jenny Collier, Imperial College, London
Breaching of the Dover Strait and the creation of “Island Britain”
14th May 2020
The UK Rockall Basin forms part of the NE Atlantic margin and is truly a frontier basin. With only 12 exploration wells, all drilled between 1980 and 2006, it is one of the most underexplored areas of the UK Continental Shelf (UKCS). Of the 12 wells, 11 were dry holes and one, the Benbecula (154/01-1) well, discovered a sub-commercial gas accumulation. This low historic success rate, together with the harsh NE Atlantic operating environment and the lack of infrastructure have created a negative view of the exploration potential of the UK Rockall Basin. Exploration in the basin is perceived by the industry at large to be high risk and low reward. However, considerable advances have been made in the understanding of Atlantic Margin geology since the last well was drilled in the Rockall Basin. Re-evaluation of drilling results in light of the current understanding of NE Atlantic Margin geology reveals that previous drilling efforts may have been hampered by a misunderstanding of the geological development of the basin and that viable untested plays may exist within the basin.
Further reading: see http://www.rockallbasin.com/
The United Downs Deep Geothermal Power project is the first development of its kind in the UK. It is located near Redruth in west Cornwall and is part-funded by the European Regional Development Fund and Cornwall Council. Two wells have been drilled to intersect a target fault structure that, it is hoped, will provide enough natural permeability to allow circulation between the wells and the generation of between 1 and 3MWe.
Drilling began in November 2018 and was completed at the end of June 2019. The production well reached a depth of 5,275m (MD) and the injection well 2,393m (MD), and the project is now in its evaluation phase.
Peter will outline the geothermal resources in Cornwall, describe the development of the UDDGP project and give an update on progress.
Background reading: see https://www.uniteddownsgeothermal.co.uk/
We need mineral resources to underpin a good quality of life for the still-expanding population of planet Earth. Although we might ultimately develop a “circular economy” where all resources are recycled, this is a long way off and we will need to continue to extract minerals for many years to come. However, the mining industry is under a variety of pressures, both geological and anthropogenic, which make it ever harder to operate economically. The industry needs to be moving to more sustainable operations, in particular reducing carbon emissions and ensuring it earns the consent of the local and global communities – the so called Social Licence to Operate.
At Leicester, we have developed an exciting breakthrough technology using ionic liquids that has the potential to revolutionise the processing of mineral ores to metals in a green and environmentally-friendly way. We have the potential to replace the use of cyanide in industrial gold extraction and the uncontrolled use of mercury by artisanal gold miners – one of the biggest sources of mercury contamination on the planet. Ultimately, the mine of the future, might not involve a hole in the ground or people going underground and have a considerably smaller impact on our environment.
The talk is aimed to be accessible for non-specialists.
Background reading: Abbott AP, Al-Bassam AZM,Goddard A, Harris RC, Jenkin GRT, Nisbett F & Wieland M (2017). Dissolution of Pyrite and other Fe-S-As minerals using Deep Eutectic Solvents. Green Chemistry, 19, 2225-2233, DOI: 10.1039/C7GC00334J.
The lecture will focus on the geology of the area of the crossing along with a detailed description of the engineering works required to form the foundations of the new bridge. Far more than one geologist or one organisation was involved in the crossing’s construction and the lecture will highlight the main parties involved and their roles and responsibilities.
The crossing is built on varied geology with almost every foundation bearing on a different rock type. However, the central island of Beamer Rock and the high ground on either side of this narrowing in the Firth of Forth are formed from igneous intrusions. These igneous intrusions resisted the glacial erosion slightly better than the sedimentary rocks into which they were intruded with Beamer Rock providing an excellent foundation to support the 210 metre high central tower. The foundations for the north and south towers (as well as one of the southern piers) are founded on 25 to 30 m diameter circular steel caissons sunk to the top of the bedrock some 40-50 m below water level. Once positioned, they were sunk into the seabed by a combination of precision dredging and ballasting with concrete to guide the caisson to its desired level and position. Once the base was cleaned and inspected underwater a thick concrete plug was poured within the cylinders to offset the effect of buoyancy and allow the construction of the reinforced concrete base for the foundations towers to be undertaken in the dry. The caisson approach is not that dissimilar to how 19th century engineers approached the foundations that support the original Forth Bridge.
The remaining foundations were constructed within sheet pile cofferdams with a combination of underwater and in-the-dry construction techniques. Some of the rock types could be excavated by mechanical means while others such as the dolerite at the central island of Beamer Rock required pre-treatment with underwater blasting before excavations could commence.
The geological information gathered prior to construction was translated into 3D numerical models in order to design the foundations. Each foundation excavation was rigorously inspected either directly by engineering geologists in the dry or when underwater with the assistance of divers and for foundations in deeper waters a remote camera dome was developed to carry out inspections up to 50 m below sea level in order to check that the design assumptions had been met or exceeded. The engineering expertise of the designer and contractor enabled the delivery of a complex set of foundations in a safe and efficient manner.
Sedimentary systems are under the influence of a variety of processes that can vary considerably in time (seconds to millennia) and space (from the grain to basin scale). This talk will examine the spatial variability in fluvial response to the Paleocene-Eocene Thermal Maximum (PETM). The PETM occurred ~56 Ma and was a geologically abrupt global warming event in which temperatures increased from 5-8°C over ~200,000 years due to a global release in carbon, making it a close analogue to today’s global warming trends. The PETM has been interrogated at a number of terrestrial and marine localities across the globe; however, the majority of these studies are not placed within a well-defined spatial and temporal context, with study often limited to single successions and the deposits that lie immediately above and below the event. It is imperative that background “normal” conditions are understood in order for an assessment of response magnitude and extent to be made. Within this talk sedimentological observations from multiple PETM localities within the Bighorn Basin, Wyoming, will be presented within a newly defined quantified basin context.
Background reading: Owen, A., Hartley, A.J., Ebinghaus, A., Weissmann, G.S. & Santos, M.G.M. (2019). Basin‐scale predictive models of alluvial architecture: Constraints from the Palaeocene–Eocene, Bighorn Basin, Wyoming, USA. Sedimentology, 66(2), 736-763. (doi:10.1111/sed.12515)
This talk will cover the past, present and future of wildfires and their environmental effects and especially the role of fire in Earth systems processes. In particular I will concentrate on modern and ancient fires, their products (charcoal) and effects, including the rise of fire in the Devonian, the evolution of late Palaeozoic fire systems and evidence for fire at the Paleocene-Eocene Thermal Maximum (PETM).
Charcoal preserves the anatomy of the plants that have been burnt. Scanning electron microscopy is routinely used to study their morphology and anatomy and new methods of obtaining temperature of charcoal formation using reflected light microscopy have been developed. This has implications for both studies of natural wildfires as well as for our understanding of the human use of wood and charcoal as a fuel.
Biogeochemical modelling suggests significant variation of atmospheric oxygen in deep time. Using a charcoal proxy for atmospheric oxygen over the past 350 million years there is evidence for significantly high levels of oxygen in the late Palaeozoic and in the Cretaceous suggesting high levels of fire at that time. This resulted in the rapid spread of weedy flowering plants in the Cretaceous.
Studies of palaeocharcoal can also delineate changes in fire over the past 20,000 years. There is a strong link between fire and climate with increased fire during periods of rapid climate change.
Scott, A.C., Bowman, D.J.M.S., Bond, W.J., Pyne, S.J. and Alexander M. 2014. Fire on Earth: An Introduction. J. Wiley and Sons. 413 pp.
Scott, A.C., Chaloner, W.G., Belcher, C.M., Roos, C.I. (eds). 2016. The interaction of fire and mankind. Phil. Trans. R. Soc. 371, Issue 1696. 252 pp.
Scott, A.C. 2018. Burning Planet. The story of fire through time. Oxford University Press. 224 pp.
Scott, A.C., Hilton, J., Galtier, J. & Stampanoni, M. 2019, A Charcoalified Ovule Adapted for Wind Dispersal and Deterring Herbivory from the Late Viséan (Carboniferous) of Scotland, International Journal of Plant Sciences, 180, pp. 1059-1074.
Scott, A.C. 2020. Fire. A very short introduction. Oxford University Press. 144 pp.
For much of our pre-history, a permanent land bridge existed between Britain and France at the Dover Strait. How and when it was removed, however, was previously unknown. We analysed a new regional bathymetric map of part of the English Channel derived from a compilation of both single- and multi-beam sonar data, which shows the morphology of the seabed in unprecedented detail.
We observed a large bedrock-floored valley that contains a distinct assemblage of landforms, including streamlined islands and longitudinal erosional grooves, which are indicative of large-scale subaerial erosion by high-magnitude water discharges. Our observations support the megaflood model, in which breaching of a rock dam at the Dover Strait (see artist’s impression on front cover) instigated catastrophic drainage of a large pro-glacial lake in the southern North Sea basin. This flow was one of the largest recorded megafloods in history and could have occurred 450,000 to 200,000 years ago.
We suggest that megaflooding provides an explanation for the permanent isolation of Britain from mainland Europe during interglacial high-sea-level stands. The breaching likely affected patterns of early human occupation in Britain by creating a barrier to migration which possibly explains the complete absence of humans in Britain 100,000 years ago. The breach of the ridge, and subsequent flooding, also may have initiated the large-scale reorganisation of the river drainages in north-west Europe by re-routing the combined Rhine-Thames River through the English Channel to form the Channel River.
Gupta, S., Collier, J.S. et al. 2007. Catastrophic flooding origin of the shelf valley systems in the English Channel, Nature, 448, pp. 342-345.
Collier, J.S. et al. 2015. Streamlined islands and the English Channel megaflood hypothesis, Global & Planetary Change, 135, pp. 190-206.
Gupta S., Collier J.S. et al. 2017. Two-stage opening of the Dover Strait and the origin of island Britain, Nature Communications, 8.
Collier, J.S. 2017: A megaflood in the English Channel. Astronomy & Geophysics, 58, 2.38-2.42.