Upcoming Talks (<front>)

Abstract not available

• Speaker: Alex Lui, Department of Earth Sciences, University of Cambridge
• Tuesday 30 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.

Add to your calendar or Include in your list

The cycling of carbon between the deep Earth and the atmosphere plays a significant role in modulating global climate. While carbon degassing at volcanic arcs are generally assumed to be the main contributor to atmospheric carbon, our research reveals that mid-ocean ridge degassing surpasses arc emissions before 50 Ma. Combining thermodynamic modelling of subducting carbon reservoirs with reconstructions of remobilised crustal carbon through the Phanerozoic, we show that volcanic arc emissions reduce to merely ~12% of mid-ocean ridge outflux before 120 Ma. This reflects the absence of deep-sea carbonate sediments entering subduction zones, leaving less voluminous metamorphic degassing of continental carbonate platforms next to convergent margins as the main mechanism for arc CO2 degassing. We find that the balance between oceanic volcanic outgassing and removal of carbon via subduction tracks major climate shifts, including the Late Palaeozoic, Late Cretaceous and Cenozoic icehouse climates.

• Speaker: University of Sydney
• Wednesday 24 April 2024, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.

Add to your calendar or Include in your list

Water electrolysis stands as a cornerstone technology for green hydrogen production from renewable energy and consists of two half-cell reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The sluggish kinetics of the state-of-the-art OER electrocatalysts based on iridium oxide severely limit the overall efficiency of the process and, consequently, its economic viability. An in-depth comprehension of the atomic-level mechanisms governing this reaction is considered essential for designing enhanced materials and advancing the transition to a sustainable and resilient energy sector. In situ structural characterization techniques, such as X-ray absorption spectroscopy and X-ray photoelectron spectroscopy, serve this purpose well as they enable real-time monitoring of the chemical composition, structural phase, and electronic configuration of the species at the gas/liquid/solid interface during the interfacial electrocatalytic turnover. In this talk, I will present an overview of the experimental approaches developed in our group and by others to probe the reactive interface during OER , as well as our current understanding of the reaction mechanism on Ir-O-based systems gained using both soft and hard X-ray spectroscopic techniques.

References

1) R Arrigo, M H ävecker, ME Schuster, C Ranjan, E Stotz, A Knop-Gericke et al.,

In situ study of the gas-phase electrolysis of water on platinum by NAP -XPS,

Angewandte Chemie International Edition 52 (2013), 11660-11664

2) JJ Velasco‐Velez, V Pfeifer, M H ävecker, RS Weatherup, R Arrigo et al., Photoelectron spectroscopy at the graphene–liquid interface reveals the electronic structure of an electrodeposited cobalt/graphene electrocatalyst, Angewandte Chemie International Edition 54 (2015), 14554-14558

3) A Knop-Gericke, V Pfeifer, JJ Velasco-Velez, T Jones, R Arrigo et al., In situ X-ray photoelectron spectroscopy of electrochemically active solid-gas and solid-liquid interfaces, Journal of Electron Spectroscopy and Related Phenomena 221 (2017), 10-17

4) V Pfeifer, TE Jones, JJV V élez, R Arrigo, S Piccinin, M H ävecker et al., In situ observation of reactive oxygen species forming on oxygen-evolving iridium surfaces, Chemical science 8 (2017), 2143-2149 5) V Pfeifer, TE Jones, S Wrabetz, C Massué, JJV V élez, R Arrigo et al., Reactive oxygen species in iridium-based OER catalysts, Chemical science 7 (2017), 6791-6795

6) JJ Velasco-Vélez, EA Carbonio, CH Chuang, CJ Hsu, JF Lee, R Arrigo, et al., Surface electron-hole rich species active in the electrocatalytic water oxidation, Journal of the American Chemical Society 143 (2021), 12524-12534

7) JJV V élez, D Bernsmeier, TE Jones, P Zeller, E Carbonio, CH Chuang, et al., The rise of electrochemical NAPXPS operated in the soft X-ray regime exemplified by the oxygen evolution reaction on IrO x electrocatalysts, Faraday discussions 236 (2022), 103-125 8) J Ruiz Esquius, DJ Morgan, G Algara Siller, D Gianolio, M Aramini et al., Lithium-directed transformation of amorphous iridium (oxy) hydroxides to produce active water oxidation catalysts, Journal of the American Chemical Society 145 (2023), 6398-6409 9) M Falsaperna, R Arrigo, F Marken, SJ Freakley Alkali Containing Layered Metal Oxides as Catalysts for the Oxygen Evolution Reaction, ChemElectroChem 2024, e202300761

• Speaker: Rosa Arrigo, Uni of Salford
• Thursday 02 May 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.

Add to your calendar or Include in your list

Six talks from a variety of areas of Earth Sciences; large igneous provinces, ice core climate records, modern ocean climate systems, earthquake dynamics, geoscience communication and the Earth’s magnetic field. Also featuring highlights from industry and a Part III poster presentation session.

• Speaker: N/A
• Tuesday 23 April 2024, 11:00-16:00
• Venue: Common Room, Department of Earth Sciences.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

When considering why Earth is the only known habitable – and inhabited – world in our solar system, its magnetic field is often included as one of the many factors resulting in such favourable conditions for life. This is because magnetic fields protect planetary surfaces from harmful cosmic radiation and prevent the atmosphere from being eroded by the solar wind. Earth’s magnetic field is generated by the geodynamo; vigorous convection of electrically conductive molten metal in the outer core results in the dipolar magnetic field that surrounds our planet. We can use the signals preserved by magnetic minerals in rocks to examine the strength of Earth’s magnetic field back through geological time. However, this becomes increasingly challenging as metasomatic and metamorphic events cause these minerals to be altered or entirely replaced. Paleomagnetic records suggest that Earth’s magnetic field has been similar in strength for the last 3.5 billion years. However, there are many time periods with sparse data, and the existing data come with many caveats. New experimental approaches are now allowing paleomagnetists to revisit Earth’s early magnetic field history in a new light by combining magnetic microscopy, geochronology and petrology. By recovering more accurate records of Earth’s magnetic field strength through time questions such as how the geodynamo behaved prior to the nucleation of the inner core, and the role of Earth’s magnetic field in mediating atmospheric escape, can be addressed properly for the first time. These observations will be critical for determining whether the magnetic field really played a crucial role in creating habitable conditions on Earth’s surface.

• Speaker: Dr Claire Nichols - University of Oxford
• Tuesday 23 April 2024, 16:30-17:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

Earthquakes are a dramatic result of our dynamic planet. They pose a huge issue to the world’s population in terms of loss of life and damage to critical infrastructure. Recent research tells us that tectonic faults can creep slowly, produce ‘slow’ earthquakes over days, or fast earthquakes that travel at supersonic speeds. What have we learnt about earthquakes over the past few years that helps us to understand these different types of faulting movements? This presentation will outline different types of tectonic fault slip and explore the methods we are currently using to enhance our understanding of earthquakes.

• Speaker: Professor Daniel Faulkner - University of Liverpool
• Tuesday 23 April 2024, 14:45-15:15
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

From dodgy pubs in West London to the Royal Institution Christmas Lectures, I’ve been lucky to talk to many people about the important role geoscience plays in our everyday lives. But what have I learnt along the way? And can anything I’ve found out help us talk more productively with the public about the importance of science in society, especially as we face significant challenges such as climate change?

• Speaker: Professor Chris Jackson - Jacobs
• Tuesday 23 April 2024, 15:45-16:15
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

TBC

• Speaker: Dr Shipra Jain - University College London
• Tuesday 23 April 2024, 14:00-14:30
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

Large igneous provinces (LIPs) are formed by enormous (i.e., frequently >106 km3) but short-lived magmatic events that have profound effects upon global geodynamic, tectonic, and environmental processes. Lithospheric structure is known to modulate mantle melting, yet its evolution during and after such dramatic periods of magmatism is poorly constrained. Using geochemical and seismological observations, we find that magmatism is associated with thin (i.e., ≲80 km) lithosphere and we reveal a striking positive correlation between the thickness of modern-day lithosphere beneath LIPs and time since eruption. Our results point to systematic destruction and subsequent regrowth of lithospheric mantle during and after LIP emplacement and recratonization of the continents following eruption. These insights have implications for the stability, age, and composition of ancient, thick, and chemically distinct lithospheric roots, the distribution of economic resources, and emissions of chemical species that force catastrophic environmental change.

• Speaker: Simon Stephenson - University of Oxford
• Tuesday 23 April 2024, 11:30-12:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Sedgwick Club talks; organiser: Lucas Measures.

Add to your calendar or Include in your list

Abstract not available

• Speaker: Rosa Arrigo, Uni of Salford
• Thursday 02 May 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.

Add to your calendar or Include in your list

Extending the ice core record of climate and environmental parameters to time periods older than 800,000 years is a major international goal. The Center for Oldest Ice Exploration (COLDEX) is a US initiative to search for climate records covering the last 5 million years, including cores from blue ice regions where very old ice has been identified. This talk will discuss recent COLDEX results from one of these areas, the Allan Hills, in the Transantarctic Mountains region of East Antarctica. Ice cores from the Allan Hills contain discontinuous sections that date to as old as 6 Ma, and numerous samples with ages between 1 and 5 Ma, all dated with the 40Aratm technique. These samples provide constraints on a variety of past environmental variables, including greenhouse gases, mean ocean temperature, and Antarctic surface temperature, and create opportunities to explore other properties of climate and the environment beyond the 800 ka limit of the existing ice core record.

The Allan Hills cores and their glaciological setting are also unusual and complex, requiring new approaches to their interpretation. Ice flow, likely from a relatively local depositional area, traps old ice at shallow depths near the ice margin, albeit in a poorly understood manner. In most locations drilled so far, ice younger than 1 Ma is underlain by a relatively thin layer (20-40 m) of older material. Dating Allan Hills cores clearly shows age reversals indicative of folding. Deformation of dust and tephra bands at the surface, and deformation of bubbles at depth, also indicate complex ice flow. Three-dimensional mapping of electrical conductivity and isotopic measurements in large, 24-cm diameter cores clearly shows inclined layers and folding. Work to decipher these complex records is ongoing.

• Speaker: Edward Brook, Oregon State University
• Tuesday 23 April 2024, 12:10-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

Add to your calendar or Include in your list

Abstract not available

• Speaker: Ed Hinton
• Thursday 04 July 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.

Add to your calendar or Include in your list

Abstract not available

• Speaker: Mai Bui, Imperial College London
• Thursday 06 June 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.

Add to your calendar or Include in your list

Abstract not available

• Speaker: Stephane Zaleski, Sorbonne University
• Thursday 23 May 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.

Add to your calendar or Include in your list

Abstract not available

• Speaker: Shelly Singh-Gryzbon, Chemical Engineering, University of Cambridge
• Thursday 09 May 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.

Add to your calendar or Include in your list

The Turkana Depression is a broad ( 500km-wide), topographically-subdued ( 0.5km), region between the elevated Ethiopian ( 1.5km) and East African Plateaus ( 2.5km). The Depression is unique in East Africa for being host to a NW-SE-trending failed Mesozoic (Anza) rift system through which the near-orthogonal, N-S-trending East African Rift subsequently developed. Whether the Depression’s low-lying nature is a result of a significantly thinned crust instigated by its multiple rifting phases, or instead due to a lack of dynamic mantle support is debated. Also poorly understood is the extent to which Cenozoic rifting and magmatism have developed across the Depression during the linkage of other comparatively narrow East African Rift zones to the north and south. Utilising data from the 2019-2021 Turkana Rift Arrays Investigating Lithospheric Structure project and surrounding networks, receiver function analysis and its joint inversion with surface-waves2, are used to probe Moho architecture and the lithosphere-asthenosphere system. Receiver function results1 reveal a thinned crust (20-25km) throughout the Depression: 10-20km thinner than the Ethiopian Plateau and Tanzania Craton. The Depression’s low elevations are thus likely an isostatic response from a thinned crust and not a lack of mantle dynamic support. High associated crustal stretching factors (β

1. Ogden, C. et al., (2023), Earth Planet. Sci. Lett., 609, 118,088, doi:10.1016/j.epsl.2023.118088. 2. Kounoudis, R. et al., (2023), Earth Planet. Sci. Lett., doi:10.1016/j.epsl.2023.118386. 3. Boyce, A., et al., (2023), Geochem. Geophys. Geosyst., 24 (8), e2022GC010,775, doi:10.1029/2022GC010775.

• Speaker: Ian Bastow, Imperial College London
• Wednesday 15 May 2024, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.

Add to your calendar or Include in your list

The cycling of carbon between the deep Earth and the atmosphere plays a significant role in modulating global climate. While carbon degassing at volcanic arcs are generally assumed to be the main contributor to atmospheric carbon, our research reveals that mid-ocean ridge degassing surpasses arc emissions before 50 Ma. Combining thermodynamic modelling of subducting carbon reservoirs with reconstructions of remobilised crustal carbon through the Phanerozoic, we show that volcanic arc emissions reduce to merely ~12% of mid-ocean ridge outflux before 120 Ma. This reflects the absence of deep-sea carbonate sediments entering subduction zones, leaving less voluminous metamorphic degassing of continental carbonate platforms next to convergent margins as the main mechanism for arc CO2 degassing. We find that the balance between oceanic volcanic outgassing and removal of carbon via subduction tracks major climate shifts, including the Late Palaeozoic, Late Cretaceous and Cenozoic icehouse climates.

• Speaker: Ben Mather, University of Sydney
• Sunday 14 April 2024, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.

Add to your calendar or Include in your list

Dissolved organic carbon (DOC) is the largest reduced carbon reservoir in modern oceans. Its dynamics regulate marine ecosystems and atmospheric CO2 levels, whereas 13C compositions track autotrophic metabolism. However, the geologic history of marine DOC remains entirely unconstrained. To address this, we developed the first direct proxy for past DOC signatures using co-precipitated organic carbon in iron ooids, and we applied this to 25 marine iron ooid-containing formations deposited over the past 1650 million years. Predicted DOC concentrations were near modern levels in the Paleoproterozoic then decreased by 90-99 % in the Neoproterozoic before sharply rising in the Cambrian. Furthermore, Proterozoic DOC was significantly 13C-depleted relative to today. I will discuss how trends likely reflect coupled changes in ocean oxygenation, particle export flux, and autotrophic 13C fractionation through geologic time.

• Speaker: Jordon Hemingway, ETH Zurich
• Tuesday 04 June 2024, 12:00-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

Add to your calendar or Include in your list

Six talks from a variety of areas of Earth Sciences; dynamic topography, mineral palaeomagnetism, science communication, rock deformation, seasonal climate events and ice cores.

• 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.

Add to your calendar or Include in your list

Abstract not available

Building doors are card operated, so latecomers may not be able to access the venue.

• Speaker: Georgina 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.

Add to your calendar or Include in your list