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Department of Earth Sciences

 

Wed 07 Feb 16:00: TBC

Earth Sciences talks - Fri, 19/01/2024 - 16:11
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Mon 22 Jan 18:00: Earth Systems Palaeobiology: using climate models to better understand the habitats of marine animals through geologic time

Earth Sciences talks - Wed, 17/01/2024 - 17:55
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!

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Climate change induced heavy rainfall could harm sea urchins

Earth Sciences news - Wed, 17/01/2024 - 12:19

As our climate warms Britain’s weather is becoming ever more extreme: with heatwaves and heavy rainfall events increasingly frequent and severe. In Scotland, winter precipitation has increased by 20% since the 1960s, and this upward trend looks set to intensify. A group of scientists from the University of Cambridge and...

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Tue 06 Feb 12:00: Antarctic summer sea-ice variability reconstructed from novel biological archives

Earth Sciences talks - Wed, 17/01/2024 - 10:04
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.

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Wed 14 Feb 16:00: TBC

Earth Sciences talks - Tue, 16/01/2024 - 16:34
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Wed 13 Mar 16:00: TBC

Earth Sciences talks - Tue, 16/01/2024 - 14:14
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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

Earth Sciences talks - Tue, 16/01/2024 - 14:12
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.

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Wed 21 Feb 16:00: The Turkana Rift Arrays Investigating Lithospheric Structure (TRAILS) Experiment

Earth Sciences talks - Tue, 16/01/2024 - 14:08
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.

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Wed 31 Jan 16:00: TBC

Earth Sciences talks - Tue, 16/01/2024 - 14:03
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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.

Earth Sciences talks - Mon, 15/01/2024 - 13:40
The West Antarctic Ice Sheet and sea level in the last interglacial

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.

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Thu 01 Feb 11:30: TBA

Earth Sciences talks - Mon, 15/01/2024 - 10:18
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Thu 18 Jan 11:30: TBC

Earth Sciences talks - Mon, 15/01/2024 - 09:57
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Thu 15 Feb 11:30: TBA

Earth Sciences talks - Mon, 15/01/2024 - 09:53
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Thu 29 Feb 11:30: TBC

Earth Sciences talks - Mon, 15/01/2024 - 09:52
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Thu 22 Feb 11:30: High-performance Computing to Support Wind Energy Research

Earth Sciences talks - Mon, 15/01/2024 - 09:51
High-performance Computing to Support Wind Energy Research

High-performance computing (HPC) has emerged as a crucial tool for advancing wind energy research and development. The ever-increasing demand for clean and renewable energy sources, coupled with the inherent complexities of wind energy systems, requires the use of HPC to address the various challenges in this field. This talk will highlight the significance, applications, and potential benefits of HPC for wind energy research.

I will briefly introduce the open-source framework Xcompact3d, dedicated to the study of turbulent flows on HPC systems. Based on high-order finite-difference schemes on a Cartesian mesh, it combines accuracy, efficiency, versatility and scalability. Xcompact3d can be used as a wind farm simulator for simulating and analysing wind energy scenarios in a virtual environment. I will present a collection of results ranging from the study of the stability of wind turbine tip vortices, the entrainment process in large-scale wind farms, some layout optimisations with complex terrains, and some power maximisation studies using wake steering.

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Tue 30 Jan 12:00: At the Edge of Reactivity: Exploring the Dynamics of Fluid-Mineral Interactions

Earth Sciences talks - Mon, 15/01/2024 - 08:27
At the Edge of Reactivity: Exploring the Dynamics of Fluid-Mineral Interactions

Determining the dynamics of reactive fluid-rock interaction is critical for uncovering the geochemical and geodynamic evolution of the lithosphere and their application in industries like CO2 storage and geothermal energy development. Geological evidence suggests that fluid-rock interactions can self-generate fluid pathways, forming a transient network of pores and fractures through mineral replacement reactions. In my presentation, I will highlight our recent research on: (1) the extent of crystallization forces in positive solid volume-changing replacement reactions, essential for reaction-induced fracturing, (2) the impact of nanoconfinement on the physical properties of geofluids and its influence on rock reactivity, and (3) the latest advances in combining 4D (3D plus time) synchrotron X-ray tomography with advanced deep-learning techniques and statistical microstructural analysis to track transient phenomena in evolving porous media.

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Tue 23 Jan 12:00: A paleoclimate perspective on the (in)stability of the West Antarctic Ice Sheet

Earth Sciences talks - Fri, 12/01/2024 - 13:50
A paleoclimate perspective on the (in)stability of the West Antarctic Ice Sheet

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. Because the timescales for ice sheets are long, our best hope of constraining the solutions is to look at the past behaviour of WAIS . Two periods are of particular interest. The end of the last glacial period is a time when we know that ice was retreating from its glacial extent, so we can study the pace of retreat. The last interglacial (LIG) is a particularly important time because Antarctic temperature was higher than present and some models predict the complete loss of WAIS and of the large ice shelves adjacent to it.

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 , but is expected to have maintained an independent ice flow because of the protection afforded by the Ellsworth Mountains. The ice core has been processed and analysed continuously for a range of analytes, including water isotopes, methane and major chemistry.

Our analyses show that the core is continuous through the last glacial period, and most of the last interglacial. Folds occur near the base, in the ice at the older end of the LIG , so that although older ice may be present, we can only interpret the core to 125 ka.

Here, I will show what happened to the ice around Skytrain Ice Rise in the Holocene and the LIG , and discuss the implications for the rate and extent of future ice loss.

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