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The Godwin Laboratory for Palaeoclimate Research

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Upcoming Talks

Thu 25 Feb 15:00: Volatiles in Earth’s mantle: primordial or subducted? Insights from new generation nitrogen and sulfur isotope systematics

From Department of Earth Sciences seminars. Published on Jan 27, 2021.

Volatiles in Earth’s mantle: primordial or subducted? Insights from new generation nitrogen and sulfur isotope systematics

Hydrothermal 15N15N abundances constrain the origins of mantle nitrogen

Nitrogen (N) is the main constituent of the Earth’s atmosphere, but its provenance in the Earth’s mantle is uncertain. In this presentation, we discuss nitrogen enrichments in multiple mantle reservoirs. We show that subduction may not be as important as previously thought to account for mantle nitrogen. We use the rare 15N15N isotopologue of N2 as a novel tracer of air contamination in volcanic gas effusions. By correcting for air contributions in the gases using this tracer, we derive new estimates for mantle 15N and N2/3He ratios from multiple volcanic regions. We focus on Yellowstone, a primitive hotspot, and the central American subduction zone. We show that subduction may cause elevated 15N and N2/3He values in a mantle source, as the result of the accumulation of surface-derived components. However, our 15N15N-based analysis requires the Yellowstone plume to have some of the lowest N2/3He ratio. This is inconsistent with subducted volatiles in this mantle source, and allows plume nitrogen to be a primordial component. This result opens the possibility that the budget of mantle volatiles was at least partly established during planetary formation, rather than exclusively reflecting subduction and tectonic plate activity.

Isotopic evidence of multiple sulfur sources delivered to the Samoan islands

Like nitrogen, sulfur isotopes can be used as a tool in placing constraints on crustal recycling and the nature of volatiles in primordial mantle reservoirs. Basalts from the Samoan islands sample contributions from all classical mantle endmembers, including extreme EM II and high 3He/4He components, as well as dilute contributions from the HIMU , EM I, and DM components. The geochemical heterogeneity of the Samoan islands provides an opportunity to test whether distinct S-isotope compositions are delivered to the Samoan mantle plume and whether they are linked to the various observed mantle components. Through high precision, quadruple S-isotope analyses of Samoan Basalts we observe unique S-isotope compositions linked to the HIMU , EM II, and EM I components at Samoa. We also use relationships between sulfur and tungsten isotopes to show that the primordial S-isotope composition of the mantle is within uncertainty of the convective mantle, suggesting S isotope compositions were well mixed within 60 Ma of Earth’s accretion.

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Thu 04 Feb 15:00: Paleocene–Eocene climate and carbon cycle: tales from the 'boring background'

From Department of Earth Sciences seminars. Published on Jan 26, 2021.

Paleocene–Eocene climate and carbon cycle: tales from the 'boring background'

The Paleocene and Eocene Epochs (~66–34 Ma) were important greenhouse periods, characterised by high frequency orbitally-paced events (e.g., hyperthermals) superimposed on long term changes in climate and the carbon cycle. Major changes in the marine and terrestrial biosphere also occurred at this time, synchronous with both high frequency and long-term changes in climate. While many detailed palaeoclimate records have been generated for the enigmatic hyperthermals, such as the Paleocene Eocene Thermal Maximum (PETM), the general background climate of this period has only been reconstructed at a much lower resolution. This poorly characterised ‘boring background’ hampers our understanding both of the overall climate state of this greenhouse world and the hyperthermals themselves. Here I’ll talk through some new data from the ancient Atlantic and Indian Oceans which help to better characterise background climate and carbon-cycle of the Palaeocene–Eocene.

Three supporting papers:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019PA003556

https://www.sciencedirect.com/science/article/pii/S0012821X20303587

https://science.sciencemag.org/content/369/6509/1383.abstract?casa_token=0BWfLrOWyjgAAAAA:AHypTjer434afTBpW43UNHxIH5lALOtLKGbNWpMUugHl3l1L8IbeTuEAKlVhkUrl5_79yL4KtIlZxEw

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Thu 25 Mar 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Jan 23, 2021.

Title to be confirmed

Abstract not available

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Thu 28 Jan 15:00: Psyche: Journey to a Metallic World

From Department of Earth Sciences seminars. Published on Jan 23, 2021.

Psyche: Journey to a Metallic World

“Psyche” is both the name of an asteroid in the main belt, orbiting out past Mars, and the name of our mission to visit that asteroid. Psyche’s density, radar, and reflected light properties indicate that it is largely made of metal. Humans have never visited a world made of metal. So if Psyche turns out to be what we think, we’ll be visiting a new kind of world.

Our spacecraft will launch in August 2022 – just 19 months away! – and in 2026 will begin orbiting Psyche and performing carefully planned scientific measurements. In this talk we’ll discuss the state of the mission and our plans, and, especially, what we each are doing on the mission and how we got here.

Psyche will surprise us. The universe always outsteps even our best imaginations. And our whole Psyche team looks forward to sharing all we discover with everyone here on Earth.

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Mon 01 Feb 17:00: Improving EDI in academic and field settings

From Department of Earth Sciences seminars. Published on Jan 22, 2021.

Improving EDI in academic and field settings

An audit for action: strategies for change

2020 saw the geosciences community reaffirm its commitment to the development of a fairer and more equal field, especially in terms of racial equality. However, developing strategies to address the challenges of poor representation can be challenging, especially if we wish to do this in a way that does not further burden minority groups to make the changes we wish to see. Here, I will present a potential strategy for identifying barriers to inclusion and retention within academic geoscience settings, based upon work first undertaken in the Department of Earth Sciences at the University of Oxford, and now being expanded across other departments in the UK. Finally, this work will discuss how similar strategies may be replicated (or preferably improved!) at other institutions, recognising that this is only one possible avenue to achieving change.

Happy Campers; perspectives on equality, diversity and inclusivity in geoscience fieldwork

Due to the unprecedented COVID -19 pandemic and growing awareness of the need for improved equality, diversity and inclusivity in the geosciences, the role of fieldwork has increasingly been called into question in recent literature and social media. In this contribution, drawing on my own experiences of working in the Highlands of Scotland, I describe how in the right place, with supportive people, adequate provisions and thorough planning, fieldwork can be accessible, inclusive and truly rewarding.

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Mon 22 Feb 17:00: Title TBC

From Department of Earth Sciences seminars. Published on Jan 21, 2021.

Title TBC

Abstract not available

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Thu 18 Mar 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Jan 18, 2021.

Title to be confirmed

Abstract not available

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Wed 10 Mar 16:00: When climate loads the Earth: rheology from geodesy

From Department of Earth Sciences seminars. Published on Jan 11, 2021.

When climate loads the Earth: rheology from geodesy

Abstract not available

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Wed 10 Feb 16:00: Landscape evolution on Mars: characterizing the ancient hydroclimate using paleolake morphologies

From Department of Earth Sciences seminars. Published on Jan 11, 2021.

Landscape evolution on Mars: characterizing the ancient hydroclimate using paleolake morphologies

Fluvio-lacustrine features on the martian surface attest to a climate that was radically different in the past. Studies of valley networks and paleolakes suggest that long-lived precipitation may have persisted up to 3.7 Ga. However, because climate models have difficulty sustaining a liquid hydrosphere at the surface (>105 yr), it has been hypothesized that multiple cycles of runoff episodes may have characterized the ancient martian climate. Despite the decades-long accumulation of in-situ and remote sensing data on surface water modification features, fundamental questions on the nature of Mars’ paleoclimate and its hydrological cycle remain: (1) How much rainfall and/or snowmelt occurred during a given interval of favorable climate?; and (2) How long did these runoff-producing episodes last? Here we combine measurements of 96 open- and closed-basin lakes with simple hydrological balances to constrain catchment-averaged precipitation over a given runoff episode. We include 13 systems containing both open- and closed-basin lakes—coupled systems—which provide fully bounded precipitation estimates. We show that, on average, local precipitation was ≳4 m and ≲159 m, and the climate was semi-arid or more humid in certain regions. We integrate these results with existing climate model data to quantitatively derive runoff episode duration and its spatial distribution across the martian highlands. Importantly, these spatio-temporal hydroclimate constraints allow us to test paleoclimate model scenarios, working towards bridging the gap between geological observations and climate theory for early Mars.

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Wed 24 Feb 16:00: Once Broken, Hard to Mend: Structural Inheritance and the Quakes that Shake Our World

From Department of Earth Sciences seminars. Published on Jan 06, 2021.

Once Broken, Hard to Mend: Structural Inheritance and the Quakes that Shake Our World

The talk will be focusing on some of my studies in active tectonic regions in East Africa and intraplate regions in the United States.

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Wed 03 Mar 16:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Jan 05, 2021.

Title to be confirmed

Abstract not available

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Wed 17 Feb 16:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Jan 05, 2021.

Title to be confirmed

Abstract not available

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Thu 11 Mar 15:00: How Are Geochemical Reactions in Aquifers Connected to Climate Change Mitigation?

From Department of Earth Sciences seminars. Published on Dec 03, 2020.

How Are Geochemical Reactions in Aquifers Connected to Climate Change Mitigation?

The storage in deep saline aquifers of CO2 captured at point sources such as coal-fired power plants is a strategy that many regard as critical to limiting global warming to less than 2 degrees Celsius. But is Carbon Capture and Storage (CCS) safe? Might reactions between CO2 , the native brine, and the host rocks modify the reservoir structure within ~10,000 years? Where does the injected CO2 go and what is its fate? Can CO2 escape to the overlying drinking water aquifers to cause unwanted reactions and degrade water quality? Our ability to understand and predict geochemical reactions in aquifers is critical for answering these questions.

This lecture will give an overview of geological carbon sequestration efforts and of the research advances in reaction kinetics and geochemical modeling necessary to predict the safety of CO2 storage. Recent innovative research by my students and collaborators on applying non-traditional stable isotope tracers in geochemical kinetics experiments has broken new ground in near-equilibrium reaction kinetics, which is critically relevant to CCS . The Mt. Simon Sandstone in the U.S. Midwest and the Sleipner Project in Norway represent planned and fully operational industrial-scale CO2 storage projects, respectively. I will present examples of numerical simulations of CO2 fate and geochemical reactions from both projects. The connections among the hydrosphere, lithosphere, and atmosphere as well as the overlap between basic science and pressing societal needs—the hallmark of groundwater sciences—become clear through a tour of the fascinating and intriguing CCS efforts around the world.

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Thu 18 Feb 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 30, 2020.

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Abstract not available

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Thu 22 Apr 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 26, 2020.

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Abstract not available

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Thu 08 Apr 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 26, 2020.

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Thu 11 Feb 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 26, 2020.

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Thu 01 Apr 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 24, 2020.

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Thu 04 Mar 15:00: Title to be confirmed

From Department of Earth Sciences seminars. Published on Nov 24, 2020.

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