Fri 08 Mar 16:00: Extent and Implications of Dynamic Support Beneath Antartica and its Fringing Oceanic Basins
Abstract not available
- Speaker: Aisling Dunn
- Friday 08 March 2024, 16:00-17:00
- Venue: Tea Room, Old House.
- Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.
Tue 20 Feb 12:00: Rapid temperature fluctuations in the early Iceland plume revealed by olivine-spinel and melt thermometry
The generation of Large Igneous Provinces (LIPs) – huge outpourings of lavas associated with tectonic rifting – is a hotly debated topic with competing models variously invoking hot mantle plumes, insulative heating by supercontinents or edge driven convective instabilities. Mantle temperature and its temporal variation during LIP magmatism is key to distinguishing between these different models. Despite this, there are as yet no detailed stratigraphically constrained studies of mantle temperature through a LIP succession.
To address this, we have applied olivine-spinel and melt-only thermometry to constrain mantle potential temperature through a sequence of lavas from Co. Antrim, Northern Ireland, formed during the earliest expression of the North Atlantic Igneous Province. Mantle potential temperature derived from olivine-spinel and melt-only methods give consistent temperature ranges of 1374–1472°C and 1403–1521°C, respectively. Notable both temperature records indicate significant (100-120°C) variation in melting temperature over a relatively short stratigraphic during earlier forming magmas and much less variation in later formed magmas, suggesting initial instability or pulsing which stabilised with time.
Variability in melting temperature is mirrored by proxies for crustal and volcanic processes; Ni contents of olivine are elevated (
- Speaker: Elliot Carter, Trinity College Dublin
- Tuesday 20 February 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 13 Feb 12:00: Data-driven slow earthquake dynamics
Earthquakes are a destructive natural phenomenon with high societal costs and impact. A better understanding and characterisation of their underlying governing equations can help to better estimate the hazard associated with them. Slow slip events (SSEs) show many similarities with regular earthquakes but are characterised by a much shorter recurrence time (months/years instead of decades/millennia), offering us the possibility to study multiple cycles. Being able to model their dynamics can answer questions concerning the complexity of the frictional failure phenomenon at natural scale and its predictability. Studying slow earthquakes in nature and in the lab, I will show how a system of Stochastic Differential Equations can help us better characterise the seismic cycle, offering an alternative way to the classical two end members (purely deterministic or purely stochastic) used to describe seismicity. Blending the deterministic and stochastic approaches shows that friction is highly sensitive to small perturbations, suggesting that the macroscopic dynamics is influenced by small scale interactions. The so-called fast degrees of freedom active at the small spatio-temporal scales can be taken into account via a stochastic framework, while the underlying low-dimensional deterministic dynamics is used as a support to describe the evolution of the system.
- Speaker: Adriano Gualandi, Department of Earth Sciences
- Tuesday 13 February 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 05 Mar 12:00: Paallavvik Island and the search for Earth's primitive water
For over a decade I have been working to answer the question ‘where did Earth source its water from?’ The answer may lie within igneous mantle plume rocks. This talk will focus on my 2021 expedition to Paallavvik Island, in search of geochemically anomalous picrite samples from the cliff sections of this uninhabited, polar-bear infested island, which sits off the east coast of Baffin Island.
- Speaker: Lydia Hallis, University of Glasgow
- Tuesday 05 March 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 31 Jan 16:00: Natural hazards in a warming world: exploring the big questions
Glacierized mountainous areas make up some of the most hazardous landscapes of our planet, and are undergoing profound changes under 21st century climatic warming. The answers to two fundamental questions are required in these areas: (i) what is the baseline hazard and risk, and (ii) are the hazard and risk likely to increase or decrease in coming decades. While these questions remain largely unanswered on a global scale, this presentation delves into the subject through a series of case studies of complex hazards in glacierized and high-mountain areas.
In this talk, I will consider both the gaps in our current knowledge, and how novel techniques and datasets help bridge these. In particular, I will discuss the two-way interactions between landslides and glaciers, improving summit ice volume estimates at glacierized volcanoes, and new optical feature tracking approaches to map slope deformation the scale of mountain ranges. The evolving hazard profile intersects with a growing population and rapidly developing infrastructure networks. As a result, a cross-disciplinary approach is essential to comprehensively analyze and mitigate risk. This talk highlights the significance of addressing these challenges and explores avenues for future research, in particular introducing the new Cambridge Complex and Multihazard Research Group (CoMHaz).
- Speaker: Max Van Wyk de Vries, University of Cambridge
- Wednesday 31 January 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 21 Feb 17:30: Microplastics from geologists' perspective 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: Saija Saarni, University of Turku
- Wednesday 21 February 2024, 17:30-19:00
- Venue: Harker 2, Department of Earth Sciences, Downing Street.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 07 Feb 16:00: TBC
Abstract not available
- Speaker: Karen Lythgoe, University of Edinburgh
- Wednesday 07 February 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Thu 15 Feb 11:30: Modelling the Response of Ice to Subglacial Flooding
Abstract not available
- Speaker: Sophie Tobin, University of Cambridge
- Thursday 15 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 22 Jan 18:00: Earth Systems Palaeobiology: using climate models to better understand the habitats of marine animals through geologic time
As Earth warms due to anthropogenic emissions, the oceans are warming and losing oxygen, posing major threats to marine animal ecosystems. Earth has warmed and cooled many times before, and the geologic record hosts evidence for ocean deoxygenation and the extinction of marine animals linked to many of these ancient warming events. Notably, the impacts of warming on ocean environments and marine ecosystems appear to have varied considerably over the Phanerozoic, with some leading to catastrophic events and others having little-to-no observable impacts on ocean oxygenation and marine biodiversity. Studies that have tried to link warming and marine extinction at the global scale have been unable to identify unifying mechanistic principles that explain this variation in the magnitude of ocean deoxygenation and extinction across ancient climate perturbations, leaving a critical knowledge gap.
In my research, I apply climate models to address fundamental questions about how environmental change has impacted Earth’s ecosystems through time. By integrating models of ancient climates, oceans and ecosystems with more traditional fossil and geochemical data, we can move from simple correlations to a more mechanistic understanding of how environmental change impacted marine ecosystems through Earth history. We aim to provide a transformative new perspective on ancient environments by linking global-scale climate to the ocean-, ecosystem- and organism-scales that are critically important to ocean oxygenation and marine animal ecology. The power of Earth system models in simulating ecological responses to deep-time environmental change is only recently being explored, so there is lots of exciting research to get involved in!
- Speaker: Richard Stockey - University of Southampton
- Monday 22 January 2024, 18:00-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Sedgwick Club talks; organiser: Lucas Measures.
Tue 06 Feb 12:00: Antarctic summer sea-ice variability reconstructed from novel biological archives
Antarctic sea ice is a critical component of the climate system, affecting a range of physical and biogeochemical feedbacks, and supporting unique ecosystems. During the Last Glacial period, Antarctic sea ice was more extensive than today, but uncertainties remain in geological (marine sediments), glaciological (ice core), and climate model reconstructions of past sea-ice extent.
Here, we present a novel archive of past sea-ice environments from regurgitated stomach oils of snow petrels (Pagodroma nivea), recovered from breeding colonies in Dronning Maud Land, Antarctica. Our reconstructions span the last ~50,00 years, during which time Antarctic sea ice expanded to its maximum extent, then retreated from the Last Glacial Maximum and the Holocene. In this talk I’ll outline how we are unpicking the complex multi-proxy signals of diet and environmental change, and how these might link to changes in the Antarctic ice sheet and Southern Ocean circulation over the same time intervals.
- Speaker: Erin McClymont, Durham University
- Tuesday 06 February 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 14 Feb 16:00: TBC
Abstract not available
- Speaker: Maximilian Werner, University of Bristol
- Wednesday 14 February 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Wed 13 Mar 16:00: TBC
TBC
- 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.
Wed 28 Feb 16:00: The Tristan da Cunha mantle plume, new insights from geophysical, petrological and geochemical studies along the Walvis Ridge hotspot track and at Tristan da Cunha Island
Tristan da Cunha is a hotspot in the South Atlantic Ocean, located 450 km east of the Mid-Atlantic Ridge. The intraplate volcanoes and seamounts that form the Tristan da Cunha archipelago are connected to the Cretaceous (132 Ma) Etendeka continental flood basalt province in Namibia via the aseismic Walvis Ridge. The ridge is built-up by seamounts chains and submarine volcanic plateaus that show a clear age progression and extend from the Namibian continental margin (northeast) to the volcanic islands of Tristan da Cunha and Gough (southwest). This age-progressive distribution of volcanic rock samples collected from the Walvis Ridge and the Rio Grande Rise west of the Mid-Atlantic Ridge provide evidence for the volcanism at Tristan da Cunha and the formation of Cretaceous flood basalts in Namibia and Brazil to be due to a common hotspot source, with the Walvis Ridge and the Rio Grande Rise documenting the hotspot tracks. The Tristan da Cunha-Walvis Ridge system is one of the few examples of a complete hotspot track, and thus the it is generally assumed to be a surface expression of a long-lasting mantle plume. However, a debate continues about whether the mantle plume beneath Tristan da Cunha is an expression of convection of the whole mantle or of shallower plate-driven convection. NW Namibia, the Walvis Ridge, Tristan da Cunha, and the South Atlantic Ocean in general were target regions for various international geophysical and geochemical projects over the past two decades, including a recent IODP expedition to the Walvis Ridge. In my talk, I will summarize the recent findings with a special focus to the crust and upper mantle structure beneath the region around Tristan da Cunha.
- Speaker: Wolfram Geissler, Alfred Wegener Institute
- Wednesday 28 February 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 21 Feb 16:00: The Turkana Rift Arrays Investigating Lithospheric Structure (TRAILS) Experiment
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 21 February 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 31 Jan 16:00: TBC
TBC
- Speaker: Max Van Wyk de Vries, University of Cambridge
- Wednesday 31 January 2024, 16:00-17:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 07 Feb 17:30: The West Antarctic Ice Sheet and sea level in the last interglacial Building doors are card operated, so latecomers may not be able to access the venue.
There is intense interest in the future stability of the West Antarctic Ice Sheet (WAIS). Models range widely in their predictions and in the physics they include. We can constrain possible outcomes by observing what happened to ice sheets at previous times when the polar regions were warmer than present. The last interglacial (LIG) is a particularly important time because both Greenland and Antarctic temperature were higher than present and so was sea level.
Within the WACSWAIN (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) project, in 2019 we retrieved a 651 metre ice core to the bed of Skytrain Ice Rise. This ice rise is adjacent to the Ronne Ice Shelf and the WAIS , an therefore sensitive to their extent. The ice core has been processed and analysed continuously for a range of analytes, and we can show that ice from the LIG is present.
I will start by describing the project, fieldwork and analyses. Eventually, I will show what happened to the ice around Skytrain Ice Rise in the LIG , and discuss how this fits with other evidence about LIG sea level.
Building doors are card operated, so latecomers may not be able to access the venue.
- Speaker: Eric Wolff, Department of Earth Sciences, and the WACSWAIN team
- Wednesday 07 February 2024, 17:30-19:00
- Venue: Harker 2, Department of Earth Sciences, Downing Street.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Thu 18 Jan 11:30: Understanding multihazard in a warming world: landslides and cryospheric hazards in the 21st Century
Abstract not available
- Speaker: Maximillian Van Wyk de Vries, Uni of Cambridge
- Thursday 18 January 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 22 Jan 18:00: Earth Systems Palaeobiology: using climate models to better understand the habitats of marine animals through geologic time
Abstract not available
- Speaker: Richard Stockey - University of Southampton
- Monday 22 January 2024, 18:00-19:00
- Venue: Harker 1, Department of Earth Sciences, Downing Street.
- Series: Sedgwick Club talks; organiser: Lucas Measures.
Thu 01 Feb 11:30: TBA
Abstract not available
- Speaker: Professor Bruce Sutherland, Uni of Alberta
- Thursday 01 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.
Thu 18 Jan 11:30: TBC
Abstract not available
- Speaker: Maximillian Van Wyk de Vries, Uni of Cambridge
- Thursday 18 January 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.