Tue 28 May 12:00: Towards a 500 Million-Year History of Earth’s Atmospheric CO2
Earth’s atmospheric CO2 concentration for the Phanerozoic Eon (the last 540 million years) has been estimated from proxies and models with varying degrees of success, resulting in considerable discrepancies between estimates. Recent advances in applying boron isotopes to foraminifera have revolutionised our understanding of Cenozoic CO2 levels (the last 66 million years) leading to a growing consensus for Earth’s more recent history. However, questions remain about the limitations of the boron isotope proxy as dependent on the extent of preservation of marine sediments and, consequently, deep-time boron-based reconstructions from Earth’s rock record have been regarded as controversial. In this talk, I will make the case that the boron isotope composition of well-preserved brachiopod shells provides a robust tool for extending our knowledge of CO2 throughout the Phanerozoic, and by showcasing new Mesozoic and Palaeozoic records I will review the role of CO2 in Earth’s major climate transitions and mass extinction events.
- 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 28 May 12:00: Towards Robust Reconstruction of Phanerozoic Atmospheric CO2 Levels
Earth’s atmospheric CO2 concentration for the Phanerozoic Eon (the last 540 million years) has been estimated from proxies and models with varying degrees of success, often resulting in considerable discrepancies between estimates. Recent advances in the applying boron isotopes to foraminifera have revolutionised understanding of Cenozoic CO2 levels (the last 66 million years), although gaps still exist. However, questions remain about the limitations of the boron isotope proxy as dependent on the extent of preservation of marine sediments and, consequently, deep time boron-based reconstructions from Earth’s rock record have been regarded as controversial. In this talk, I will make the case that the boron isotope composition of well-preserved brachiopod shells provides a robust tool for extending our knowledge of CO2 throughout the Phanerozoic, and by showcasing new Mesozoic and Palaeozoic records I will review the role of CO2 in Earth’s major climate transitions and mass extinction events.
- 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.
Wed 15 May 14:00: The Turkana Rift Arrays Investigating Lithospheric Structure (TRAILS) Experiment
The Turkana Depression is a broad, topographically-subdued, region between the elevated Ethiopian and East African Plateaus. 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-waves, are used to probe Moho architecture and the lithosphere-asthenosphere system.
- 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.
Thu 09 May 11:30: Engineering solutions for heart valve disease using computational modelling and simulation
Transcatheter valve replacement is a revolutionary, minimally invasive alternative to surgery for patients with heart valve disease. With over 1.5 million procedures performed worldwide and expectations of a sharp increase in the coming years, there is growing concerns about the rise in adverse events such as coronary obstruction and valve thrombosis. It is anticipated that the interaction between the implanted transcatheter heart valve with patient-specific anatomy may give rise to unfavourable hemodynamics, contributing to these adverse events. In this seminar, we will explore the role of computational modelling and simulation in improving our mechanistic understanding of these events, and as a tool to assist clinicians in patient selection and pre-procedural planning, ultimately improving patient outcomes.
- 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.
Wed 05 Jun 17:30: Extreme glacial implies discontinuity of early human occupation of Europe Building doors are card operated, so latecomers may not be able to access the venue.
The oldest known hominin remains in Europe [ca. 1.5 to 1.1 million years ago (Ma)] have been recovered from Iberia, where paleoenvironmental reconstructions have indicated warm and wet interglacials and mild glacials, supporting the view that once established, hominin populations persisted continuously. We report analyses of marine and terrestrial proxies from a deep-sea core on the Portugese margin that show the presence of pronounced millennial-scale climate variability during a glacial period ca. 1.154 to 1.123 Ma, culminating in a terminal stadial cooling comparable to the most extreme events of the last 400,000 years. Climate envelope–model simulations reveal a drastic decrease in early hominin habitat suitability around the Mediterranean during the terminal stadial. We suggest that these extreme conditions led to the depopulation of Europe, perhaps lasting for several successive glacial-interglacial cycles.
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: Small Lecture Theatre, Department of Geography, Downing Site.
- Series: Quaternary Discussion Group (QDG); organiser: Jinheum Park.
Wed 08 May 14:00: Searching for habitability on Venus and exoplanets
Venus today presents a type example of how habitability can fail to persist on a planet: rocky and to a first order overwhelmingly Earth-like, but with a climate profoundly hostile to life’s complex molecular machinery. But, was it always like this and will we know a Venus from an Earth when we see one elsewhere in the galaxy? This talk investigates what evidence there may be to constrain Venus’s past climate state, and relates this to the frontier of our search for habitable conditions on exoplanets.
- Speaker: Oliver Shorttle, University of Cambridge
- Wednesday 08 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 16 Oct 14:00: Title to be confirmed
Abstract not available
- Speaker: Kristel Chanard -- IPGP, Paris
- Wednesday 16 October 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Wed 01 May 14:00: New Insights from the Collaboratory for the Study of Earthquake Predictability (CSEP)
As seismology enters the era of statistical aftershock forecasting and continuous real-time seismic hazard estimation, the community needs independent model evaluation methodology to provide the best available science and to understand its current limitations. CSEP is a global community with a mission to improve earthquake forecasting by comparative model testing in a truly prospective manner (i.e., against data not yet available during model development). In this talk, I will provide an overview of new insights into earthquake predictability gained by CSEP experiments around the globe and over nearly two decades. I will illustrate how these insights are informing national seismic hazard models and real-time forecasting.
- Speaker: Max Werner -- University of Bristol
- Wednesday 01 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Wed 29 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Patrick Smith -- Dublin Institute for Advanced Studies
- Wednesday 29 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre (virtual).
- Series: Bullard Laboratories Wednesday Seminars; organiser: Janneke de Laat.
Wed 29 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Patrick Smith -- University of Leeds
- Wednesday 29 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre (virtual).
- Series: Bullard Laboratories Wednesday Seminars; organiser: Janneke de Laat.
Wed 12 Jun 14:00: Title to be confirmed
Abstract not available
- Speaker: Gianmarco Mengaldo -- NUS, Singapore
- Wednesday 12 June 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Wed 05 Jun 14:00: Title to be confirmed
Abstract not available
- Speaker: Brad Foley -- Penn State University
- Wednesday 05 June 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: nobody.
Wed 08 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Kristel Chanard -- IPGP, Paris
- Wednesday 08 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
Wed 01 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Max Werner -- University of Bristol
- Wednesday 01 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.
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.
The Pacific Walker Circulation (PWC) is an important part of the global climate system, and affects weather and climate all over the world. However, our observational records of the climate system are too short to characterise the PWC ’s long-term internal variability, as well as how the PWC responds to external forcings such as volcanic eruptions and anthropogenic forcings.
In this seminar I will share a reconstruction of the PWC ’s behaviour over the past 800 years. I will outline how I calculated this reconstruction using a network of globally-distributed water isotope proxy records, as well as how I quantified uncertainties from different sources. I will share some new insights this reconstruction has allowed, including a close examination of the PWC ’s response to both volcanic and anthropogenic forcing.
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.
Wed 05 Jun 17:30: Extreme glacial implies discontinuity of early human occupation of Europe Building doors are card operated, so latecomers may not be able to access the venue.
The oldest known hominin remains in Europe [ca. 1.5 to 1.1 million years ago (Ma)] have been recovered from Iberia, where paleoenvironmental reconstructions have indicated warm and wet interglacials and mild glacials, supporting the view that once established, hominin populations persisted continuously. We report analyses of marine and terrestrial proxies from a deep-sea core on the Portugese margin that show the presence of pronounced millennial-scale climate variability during a glacial period ca. 1.154 to 1.123 Ma, culminating in a terminal stadial cooling comparable to the most extreme events of the last 400,000 years. Climate envelope–model simulations reveal a drastic decrease in early hominin habitat suitability around the Mediterranean during the terminal stadial. We suggest that these extreme conditions led to the depopulation of Europe, perhaps lasting for several successive glacial-interglacial cycles.
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 05 Jun 17:30: Extreme glacial implies discontinuity of early human occupation of Europe Building doors are card operated, so latecomers may not be able to access the venue.
The oldest known hominin remains in Europe [1.5 to 1.1 million years ago (Ma)] have been recovered from Iberia, where paleoenvironmental reconstructions have indicated warm and wet interglacials and mild glacials, supporting the view that once established, hominin populations persisted continuously. We report analyses of marine and terrestrial proxies from a deep-sea core on the Portugese margin that show the presence of pronounced millennial-scale climate variability during a glacial period 1.154 to 1.123 Ma, culminating in a terminal stadial cooling comparable to the most extreme events of the last 400,000 years. Climate envelope–model simulations reveal a drastic decrease in early hominin habitat suitability around the Mediterranean during the terminal stadial. We suggest that these extreme conditions led to the depopulation of Europe, perhaps lasting for several successive glacial-interglacial cycles.
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 24 Apr 14:00: Carbon subduction and mid-ocean ridge emissions modulate icehouse-greenhouse climates
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
- Wednesday 24 April 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Megan Holdt.
Wed 22 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Arwen Deuss - Utrecht University
- Wednesday 22 May 2024, 14:00-15:00
- Venue: Wolfson Lecture Theatre.
- Series: Bullard Laboratories Wednesday Seminars; organiser: Lisanne Jagt.
Tue 30 Apr 12:00: Fresh perspectives on the origins of major animal groups: insights from the late Ediacaran of Namibia
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.