Tue 28 May 12:00: Title to be confirmed
Abstract not available
- Speaker: Hana Jurikova, University of St Andrews
- Tuesday 28 May 2024, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.
Tue 23 Apr 12:00: Title to be confirmed
Abstract not available
- Speaker: Edward Brook, Oregon State University
- Tuesday 23 April 2024, 12:00-13:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.
Wed 24 Apr 17:30: Natural and forced behaviour of the Pacific Walker Circulation over the past 800 years Building doors are card operated, so latecomers may not be able to access the venue.
Abstract not available
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Georgnia Falster, Australian National University
- Wednesday 24 April 2024, 17:30-19:00
- Venue: Small Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 05 Jun 17:30: TBC Building doors are card operated, so latecomers may not be able to access the venue.
Abstract not available
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Vasiliki Margari, University College London
- Wednesday 05 June 2024, 17:30-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 12 Jun 17:30: Palaeoecological Insights into the Causes and Consequences of Mid-Late Quaternary Megafauna Extinction in Asia and Australia Building doors are card operated, so latecomers may not be able to access the venue.
Mid-Late Quaternary megafauna extinctions have long intrigued researchers seeking to understand the causes and consequences of these significant ecological events. What role did fluctuations in climate, shifts in vegetation composition, alterations in habitat distribution, and the impact of human settlement play in megafauna extinction? One way to help us better understand the role of environmental change in the extinction process is to use palaeoecological techniques (pollen, spore and charcoal analysis) combined with well resolved geochronological estimates to reconstruct palaeoenvironmental conditions that occur before, during, and after past megafauna extinctions. Here I present two palaeoecological case studies that provide insights into megafauna extinction in Asia and Australia: (i) the largest ever primate and one of the largest of the southeast Asian megafauna, Gigantopithecus blacki, that persisted in China from about 2.0 million years until the late middle Pleistocene when it became extinct, well before the appearance of Homo sapiens on the landscape, and (ii) the multiple extinctions of megafauna that occurred across Australia around 50,000-40,000 years ago that coincide with a time when people were present across the Australian landscape. This presentation underscores the importance of interdisciplinary approaches integrating palaeoecological, geochronological, archaeological, and climatological perspectives to unravel the complexities of past megafauna extinctions and inform strategies for mitigating future biodiversity crises.
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Simon Haberle, Australian National University
- Wednesday 12 June 2024, 17:30-19:00
- Venue: Small Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 15 May 17:30: Radiocarbon dating and conspiracy theories Building doors are card operated, so latecomers may not be able to access the venue.
A range of conspiracy theories involving radiocarbon dating have become popular on the Internet over the past years. Examples include the radiocarbon dating of dinosaur fossils that supposedly reveal problems with a geologically old Earth, claims that entire centuries of European history have been made up, and archaeological sites that supposedly provide evidence for a long-lost Younger Dryas civilization that is being hidden or denied by “Big Archaeology”. We will look at what these conspiracy theories claim, followed by more down-to-Earth explanations. We then discuss the dangers of such conspiracy theories, and provide some pointers for dealing with them.
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Maarten Blaauw, Queen's University Belfast
- Wednesday 15 May 2024, 17:30-19:00
- Venue: Large Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 24 Apr 17:30: Title to be confirmed Building doors are card operated, so latecomers may not be able to access the venue.
Abstract not available
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Georgnia Falster, Australian National University
- Wednesday 24 April 2024, 17:30-19:00
- Venue: Small Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 15 May 17:30: Radiocarbon dating and conspiracy theories
A range of conspiracy theories involving radiocarbon dating have become popular on the Internet over the past years. Examples include the radiocarbon dating of dinosaur fossils that supposedly reveal problems with a geologically old Earth, claims that entire centuries of European history have been made up, and archaeological sites that supposedly provide evidence for a long-lost Younger Dryas civilization that is being hidden or denied by “Big Archaeology”. We will look at what these conspiracy theories claim, followed by more down-to-Earth explanations. We then discuss the dangers of such conspiracy theories, and provide some pointers for dealing with them.
- Speaker: Maarten Blaauw, Queen's University Belfast
- Wednesday 15 May 2024, 17:30-19:00
- Venue: Venue to be confirmed.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Tue 23 Apr 11:00: Sedgwick Club Conference 2024
Six 25 minute talks from a variety of areas of Earth Sciences; dynamic topography, mineral palaeomagnetism, science communication, rock deformation, seasonal climate events and palaeontology.
- Speaker: Speakers to be confirmed
- Tuesday 23 April 2024, 11:00-16:00
- Venue: Department of Earth Sciences, Tilley Lecture Theatre.
- Series: Sedgwick Club talks; organiser: Lucas Measures.
Wed 05 Jun 17:30: TBC
Abstract not available
- Speaker: Vasiliki Margari, University College London
- Wednesday 05 June 2024, 17:30-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Thu 25 Apr 11:30: Specific Ion Effects in Colloidal Surface Forces
The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of the interactions of colloid particles has provided a useful framework for understanding general trends determining adsorption and aggregation of micro- and nanoparticles. The point-charge (Poisson-Boltzmann or Debye-Hückel) theory of electrolytes characterises the nature of the electrolyte solely by its pH and Debye length or ionic strength. So conventional theory is incapable of predicting the ion-specific distinction between, for instance, NaCl and KCl solutions, or between phosphate and citrate pH buffer solutions. But ion-specific phenomena (Hofmeister effects) are ubiquitous, and observed in protein aggregration, enzyme adsorption on nanoparticles, particle diffusion coefficients, charge reversal effects, bubble coalescence, lipid self-assembly, electrode capacitance.
Ion specificity essentially arises from the distinct electron structure of different ions. We identify two competing consequences. On the one hand, electronic polarisability drives ion dispersion forces [1], leading to adsorption of coions, or excess adsorption of counterions resulting in charge reversal [2]. On the other hand, the size of the electron cloud drives ionic steric forces, resulting in a limit to the concentration of adsorbed ions that results, for instance, in a diminution of electrode capacitance [3].
We account for these effects as additional nonelectrostatic contributions to the total chemical potential of ions, applied in a modified Poisson-Boltzmann model. For basic development of the ideas we use symmetry to simplify the geometry to 1D calculations. But implementing the solution using finite element methods, we obtain a framework that will be used to model the complex 3D geometries of porous electrodes and self-assembled lipid crystal phases. One long term aim is to predict the phase transitions between hexagonal, cubic and micellar phases relevant to, for instance, the physiology of RNA (COVID) vaccines.
References
[1] Importance of Accurate Dynamic Polarizabilities for the Ionic Dispersion Interactions of Alkali Halides. D.F. Parsons, B.W. Ninham. Langmuir 2010, 26(3), 1816–1823. https://dx.doi.org/10.1021/la902533x
[2] Buffer-specific effects arise from ionic dispersion forces. D.F. Parsons, C. Carucci, A. Salis. Phys. Chem. Chem. Phys., 2022, 24, 6544. https://dx.doi.org/10.1039/d2cp00223j
[3] Thermodynamics beyond dilute solution theory: Steric effects and electrowetting. D. Tadesse, D.F. Parsons. In: Encyclopedia of Solid-Liquid Interfaces (2024). https://dx.doi.org/10.1016/B978-0-323-85669-0.00137-9
- Speaker: Drew Parsons, Assoc. Prof., University of Cagliari
- Thursday 25 April 2024, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Chris Richardson.
Thu 25 Apr 11:30: Specific Ion Effects in Colloidal Surface Forces
The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of the interactions of colloid particles has provided a useful framework for understanding general trends determining adsorption and aggregation of micro- and nanoparticles. The point-charge (Poisson-Boltzmann or Debye-Hückel) theory of electrolytes characterises the nature of the electrolyte solely by its pH and Debye length or ionic strength. So conventional theory is incapable of predicting the ion-specific distinction between, for instance, NaCl and KCl solutions, or between phosphate and citrate pH buffer solutions. But ion-specific phenomena (Hofmeister effects) are ubiquitous, and observed in protein aggregration, enzyme adsorption on nanoparticles, particle diffusion coefficients, charge reversal effects, bubble coalescence, lipid self-assembly, electrode capacitance.
Ion specificity essentially arises from the distinct electron structure of different ions. We identify two competing consequences. On the one hand, electronic polarisability drives ion dispersion forces [1], leading to adsorption of coions, or excess adsorption of counterions resulting in charge reversal [2]. On the other hand, the size of the electron cloud drives ionic steric forces, resulting in a limit to the concentration of adsorbed ions that results, for instance, in a diminution of electrode capacitance [3].
We account for these effects as additional nonelectrostatic contributions to the total chemical potential of ions, applied in a modified Poisson-Boltzmann model. For basic development of the ideas we use symmetry to simplify the geometry to 1D calculations. But implementing the solution using finite element methods, we obtain a framework that will be used to model the complex 3D geometries of porous electrodes and self-assembled lipid crystal phases. One long term aim is to predict the phase transitions between hexagonal, cubic and micellar phases relevant to, for instance, the physiology of RNA (COVID) vaccines.
References
[1] Importance of Accurate Dynamic Polarizabilities for the Ionic Dispersion Interactions of Alkali Halides. D.F. Parsons, B.W. Ninham. Langmuir 2010, 26(3), 1816–1823. https://dx.doi.org/10.1021/la902533x
[2] Buffer-specific effects arise from ionic dispersion forces. D.F. Parsons, C. Carucci, A. Salis. Phys. Chem. Chem. Phys., 2022, 24, 6544. https://dx.doi.org/10.1039/d2cp00223j
[3] Thermodynamics beyond dilute solution theory: Steric effects and electrowetting. D. Tadesse, D.F. Parsons. In: Encyclopedia of Solid-Liquid Interfaces (2024). https://dx.doi.org/10.1016/B978-0-323-85669-0.00137-9
- Speaker: Drew Parsons, Assoc. Prof., University of Cagliari
- Thursday 25 April 2024, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Chris Richardson.
Thu 07 Mar 11:30: Novel processing and 3D correlative imaging of electrodes for batteries
11.30 – 12.30
Dr Chun Ann Huang, Imperial College London
Rechargeable batteries can contribute to powering electric transportation and storing electrical energy generated from intermittent renewable sources. There are increasing demands for improving the rate capability and energy density of current Li ion batteries (LIBs) and solid-state Li metal batteries (SSLMBs), along with other types of batteries. Two novel processing technologies have been developed to optimise the battery electrode microstructure and improve ion diffusion kinetics: (i) directional ice templating (DIT) for fabricating thick (900 µm) cathodes with vertical pore arrays and porosity gradient for LIBs [1]; and (ii) directional freezing and polymerisation (DFP) for fabricating cathodes with vertical arrays of solid polymer electrolyte (SPE) directly incorporated in the cathode microstructure during processing for SSLM Bs [2]. Both techniques reduced tortuosity τ of ion diffusion pathways through electrode thickness to 1.5 from ~3.3 for commercial electrodes.
We then show a new correlative imaging technique of combining X-ray Compton scattering imaging (XCS-I) and computed tomography (XCT) that allows 3D pixel-by-pixel mapping of Li chemical stoichiometry variations in a LiNi0.8Mn0.1Co0.1O2 electrode within a coin cell battery (Fig. 1) [3,4]. Using this technique, we show how the anisotropic electrode microstructure improved Li+ ion diffusivity, homogenised Li+ ion concentration, and improved energy storage performance.
13.00 – 14.00
Eric Breard – University of Edinburgh
Enigma to Understanding: A Multidisciplinary Journey into the Mechanics of Concentrated Pyroclastic Density Currents
- Speaker: Dr Chun Ann Huang, Imperial College London
- Thursday 07 March 2024, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Mon 11 Mar 18:00: Tracing horizons of habitability on Venus
Earth’s next-door neighbour, Venus, shines brilliantly in our night sky and has represented love and beauty since antiquity. Human exploration of Venus during the space age, however, revealed that its surface is boiling hot, its atmosphere is drier than the Atacama desert, and the whole planet is engulfed in thick clouds of acid. Now, almost 40 years since our last in-situ visitation of the planet Venus, humanity is sending a new fleet of probes to constrain its ancient climate history and to discover whether it may host life today. In this talk, I will trace the past and future of Venus exploration, and answer the questions: what does Venus’s ancient past mean for the habitability of exoplanets around distant stars? and how could Venus support extraterrestrial life today?
- Speaker: Sean Jordan - Institute of Astronomy
- Monday 11 March 2024, 18:00-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Sedgwick Club talks; organiser: Lucas Measures.
Wed 06 Mar 16:00: Origin of carbonatites using the triple-isotope approach
Carbonatites are rare carbonate-rich igneous rocks derived from carbon and carbonate-rich regions of Earth’s mantle. Although a number of igneous processes are recognized to have controlled their compositions, the origin of the carbonate-rich nature of these magmas remains debated and has been linked to various mantle-related processes, including subduction and plume–lithosphere interaction. High-precision isotope measurements can provide insights into carbonatite petrogenesis, including the identification of subducted crustal material in their source region. In particular, combining mass-dependent and kinetically corrected Mg isotope data, also known as the triple-isotope approach, provides insights into mass fractionation processes driving mass dependent fractionation, which in turn allows to distinguish between equilibrium and kinetic processes. In this work, we report high-precision Mg stable isotope data for 59 carbonatites and associated silicate rocks from different localities and ages ranging from 3000 Ma to present-day. In addition, we also report Mg isotope data for 17 Phanerozoic carbonate rocks, with the aim of identifying the isotopic signature of carbonate-rich material potentially recycled to the carbonatite mantle source regions. We observe positive residual deviations after kinetic mass fractionation correction of the Mg isotope data for our carbonatites; an isotope signal that is also present in Phanerozoic carbonates. This observation establishes that a component of the Mg present in these samples experienced mass-dependent equilibrium isotopic fractionation processes, which are significantly larger at low temperatures. Given that the Mg results do not covary with C and O isotopic signals, the magnitude of the fractionation following the equilibrium law observed in carbonatites provides strong evidence for recycled material from the Earth’s surface in the mantle source of Ca- and Mg-rich carbonatites. Furthermore, associated silicate rocks present mantle-like Mg isotopic compositions in contrast with the genetically linked carbonatites – based on the Sr isotopes – for some complexes, which is best explained if the carbonatites and associated silicate rocks represent distinct generation of partial melts of a mantle source containing recycled carbonate.
- Speaker: Elsa Amsellem, University of Cambridge
- Wednesday 06 March 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 06 Mar 16:00: TBC
TBC
- Speaker: Elsa Amsellem, University of Cambridge
- Wednesday 06 March 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Mon 04 Mar 18:00: Differences in Fluvial Geomorphology between Earth and Mars
There is much evidence that liquid water once flowed on the surface of early Mars. Preserved ancient landscapes altered by water provide valuable insight into the past processes on Mars, the presence of water, past environmental conditions, and habitability. To better understand the fluvial geomorphology on Mars, we use knowledge from systems on Earth. However, is it fair to do so when gravity is much lower? How does gravity affect sediment transport? And how does this, in turn, influence the morphology and stratigraphy on Mars? In this talk, I will clarify the effect of gravity on fluvial sediment transport with analytical modelling and use numerical modelling to show the effect of gravity on delta morphology.
- Speaker: Lisanne Braat - European Space Agency
- Monday 04 March 2024, 18:00-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Sedgwick Club talks; organiser: Lucas Measures.
Wed 13 Mar 16:00: Evaluating Dynamic Topography Predictions using the Stratigraphic Record
Mantle convection exerts a key control on a range of geological processes operating at Earth’s surface, such as the generation of topography, creation of accommodation space, changes in sea-level and flooding of continental interiors. A well-known example is the North American Western Interior, where geological observations require the influence of sub-plate processes to explain the observed evolution of topography. Various geodynamic models also predict that large-scale vertical motions of the region are driven by dynamic topography. In this study, we test the predictions of dynamic topography for North America using novel databases of continental uplift. The history of vertical motions of the North American Western Interior is constrained using paleo-bathymetric markers and continental-scale sediment isopach maps. These data are used to test predictions of dynamic topography from mantle circulation models. Results show that, although the general spatial patterns of dynamic topographic change can be predicted, mantle convection models struggle to predict the amplitude of dynamic topography and the polarity of change. To investigate other possible drivers of the observed, geophysical constraints on properties of the present-day shallow mantle are combined with an isostatic model to explore shallow-mantle contributions to uplift in the region.
- Speaker: Victoria Fernandes, GFZ Potsdam
- Wednesday 13 March 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Thu 29 Feb 11:30: Two topics in subsurface CO2 storage – Field scale flow modelling, and evaluating the feasibility of scaling up deployment to climate relevant scales
In this presentation I will present recent research in my group on two topics in subsurface CO2 storage.
In the first topic I will argue that small, centimetre scale, heterogeneities in multiphase flow properties will have field scale impacts on the movement of CO2 injected underground. I will demonstrate our characterisation and modelling workflows in application to simulations of CO2 storage sites of the offshore UK. In search of a validating case study, my research group has been reinterpreting seismic imagery from the Decatur CO2 storage site in the USA . I will show results of our application of an interpretation of the time-shifts from seismic surveys at this site. This has revealed CO2 migration along faults, allowing the plume to bypass lower quality units within the reservoir.
In the second topic I address questions of the representation of CO2 storage resource (pore space) use in techno-economic models used to identify scaleup trajectories and identify climate change mitigation plans. I will review the varied uses and demands for resource assessment in these projections and discuss the potential for including simplified physics and techno-economic constraints on the use of subsurface CO2 storage. I will show the results of our global analyses of CO2 storage scaleup limited by reservoir pressurisation or constraints on sustained annual growth in the deployment of projects. I argue for both a standardised reporting of current carbon capture and storage activity and an inclusion of growth modelling and physics-based contraints in the projection of future scaleup in CO2 storage.
- Speaker: Sam Krevor, Imperial College London
- Thursday 29 February 2024, 11:30-12:30
- Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
- Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.
Mon 26 Feb 18:10: Geoarchaeological evidence for climate change in Ancient Egypt
Over the past few decades, geologists have become regular contributors to archaeological digs. In Egypt, these explorations have proved a prospecting tool for ancient burials, and a useful insight to the hinterlands of many sites. By tessellation of results from many sites, we start to see a pattern of landscape change, itself driven by climate fluctuations. In the early Holocene, population was spread across the many lakes of the Saharan region but, as these dried out, they migrated into the Nile valley and started a process of ‘niche construction’, through irrigation and agriculture. In the process, humans started to divert and control the natural meandering of the Nile, devising methods to manage the climate-controlled fluctuations of the annual flood. Recent research suggests that, during periods of global warming, rainfall increased again in the Sahara and that the inhabitants returned to the desert, from the valley. Current research aims to inform the climate models by providing detailed analysis of ancient ecosystems.
- Speaker: Judith Bunbury - Department of Earth Sciences
- Monday 26 February 2024, 18:10-19:10
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Sedgwick Club talks; organiser: Lucas Measures.