Upcoming Talks (<front>)

Abstract not available

• Speaker: Isabel Papanagnou
• Friday 16 May 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: Zachary Sudholz
• Friday 20 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: Sergei Lebedev ( University of Cambridge)
• Friday 23 May 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: John Rudge
• Friday 06 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: Zachary Sudholz
• Friday 20 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: James Jackson
• Friday 13 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: John Rudge
• Friday 06 June 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract not available

• Speaker: Alex Copley
• Friday 02 May 2025, 16:00-17:00
• Venue: Tea Room, Old House.
• Series: Bullard Laboratories Tea Time Talks; organiser: David Al-Attar.

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Abstract coming soon

• Speaker: Tolulope Olugboji, University of Rochester
• Wednesday 18 June 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Tom Merry.

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The radiation of animals across the Ediacaran-Cambrian transition is one of the most transformational events in Earth history, representing a step change in the evolution of the biosphere. While fossils from the Cambrian are readily recognised as belonging to extant groups, those from the late Ediacaran Period document organisms with distinctive forms and no counterparts among living species. This has resulted in a number of different phylogenetic interpretations, ranging from animals to fungi to an extinct Kingdom but with little historical consensus. In this talk, I will focus on the rangeomorphs – frond-like taxa with ‘fractal’ branching – which are among the oldest Ediacaran macrofossils. My work uses morphogenetic pattern to produce a phylogenetic bracket for the rangeomorphs and this study of Ediacaran developmental biology has identified them as animals and stem-group eumetazoans to the exclusion of alternatives. Rangeomorphs thus occupy a critical position in the tree of animal life, post-dating the origin of true tissues and body axes, but likely pre-dating the origins of a gut and other defining eumetazoan characters. This conclusion enables us to integrate rangeomorphs into debates concerning the mode of early animal evolution, for example, in the influence of the evolving regulatory genome on the evolution of animal complexity. Some authors have suggested that a step-change in the regulation of early-acting genes implicated in development may explain the burst of morphological variety which underpins the Cambrian Explosion. However, our data suggest that rangeomorph growth was conserved and predictable with a morphogenetic strategy that was highly regulated, demonstrating that the most ancient eumetazoan fossils known already manifest evidence of complex developmental regulation. Instead, we suggest that the evolution of the rangeomorphs (and other Ediacaran macrofossils) may have catalysed the explosion of morphological variety observed during the Cambrian Explosion by promoting the diversification of novel phenotypes and behaviours through the introduction of space- and time-limited resources, resulting in a rougher fitness landscape than earlier in Earth history. Previous studies have implicated a roughening of the fitness landscape as a potential driver for the Cambrian Explosion but this hypothesis remains untested. Using eco-evolutionary simulations we propose that morphological disparity is an emergent property of a roughening fitness landscape providing a possible mechanism for saltational jumps in the evolution of morphological disparity through time, including during the Cambrian Explosion.

• Speaker: Frances Dunn, Oxford University Museum of Natural History & University of Oxford
• Tuesday 10 June 2025, 12:00-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

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Copper is an essential component in most clean energy technologies and fundamental to the success of the global green energy transition. It is mainly sourced from porphyry copper deposits (PCDs), which are metal-rich magmatic-hydrothermal systems typically associated with subduction zones. However, PCDs are rare and proving increasingly difficult to find. They are also high tonnage (100–1,000 Mt) and low concentration (average production grade is 0.53% Cu), so enormous volumes of rock must be extracted to retrieve tiny amounts of metal. As the global demand for copper surges to meet ambitious green energy targets, society is confronted with the dual challenge of locating increasingly elusive PCDs while prioritising those with the lowest potential environmental impact. This means finding the most copper-rich (highest-grade) deposits, which require the smallest amount of extraction and processing, and thus create the least damage to the environment.

The exhumation history of a PCD plays an important role in determining its copper grade. During the initial “hypogene” stage of mineralisation, rapid exhumation is required to advect heat towards the surface, allowing metal-carrying magmas and fluids to transport their cargo into the shallow crust. To maximise ore grades, exhumation must then slow considerably so the deposit can linger close to the surface where secondary “supergene” enrichment by oxygenated groundwater water takes place. In this talk, I will present an example from the Eocene-Oligocene copper belt in northern Chile, which is the world’s premier PCD province, but disappears to the north as it approaches the Peruvian border. By combining U-Pb zircon geochronology, Al-in-hornblende geobarometry, low-temperature (U-Th-Sm)/He thermochronology, and thermal-kinematic modelling to track exhumation histories, I will show that (1) both the rate and timing of exhumation are critical in determining the potential of an area to host high-grade PCDs; and (2) northward disappearance of the copper belt close to Peru is due to higher exhumation rates in that area, which prevented supergene enrichment and potentially led to loss of deposits via surface erosion.

Mineralogical Society Distinguished Lecturer 2024–25

• Speaker: Frances Cooper, University College London
• Tuesday 03 June 2025, 12:00-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

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Abstract not available

• Speaker: Tristan McKenzie, Uni of Gothenberg
• Thursday 15 May 2025, 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.

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Abstract not available

• Speaker: Dan Toy, IEEF
• Thursday 01 May 2025, 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.

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Abstract not available

• Speaker: Jeff Peakall, University of Leeds
• Tuesday 27 May 2025, 12:00-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

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Abstract not available

• Speaker: Emma Lepinay, IEEF
• Thursday 08 May 2025, 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.

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Abstract not available

• Speaker: Dan Toy, IEEF
• Thursday 01 May 2025, 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.

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Abstract not available

• Speaker: Quentin Kriaa, Uni of Cambridge
• Thursday 12 June 2025, 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.

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The precise estimation of ground displacement caused by natural hazards, such as earthquakes, volcanoes, landslides, as well as monitoring of glaciers, can be performed by comparing (or spatially correlating) two optical satellite images of the same region acquired on different dates. This technique can provide very rapid and robust constraints on ground displacement, and is especially valuable for large surface rupturing earthquakes, which typically involve very large strains in the near-field region, thus preventing the use of high precision InSAR techniques in resolving ground deformation. However, the challenge with optical correlation resides in the fact that the ground motion is generally smaller than the satellite image resolution: sub-pixel precision is therefore critical. One solution, which forms the basis of many current optical correlation methods, is to assume a uniform displacement over a small correlation window (typically between 3 and 100 pixels wide/high). However, this assumption can lead to wrong estimations, notably close to sharp discontinuities such as fault ruptures. I present here the first data-based method to perform ground displacement estimation, relying on a machine learning model and a synthetically generated surface rupture database. This database is used to train a model to retrieve the local displacement for a given image pair. It includes images containing synthetic sharp displacement boundaries in order to learn a more realistic machine learning model. Our results show that we improve the accuracy near fault ruptures compared to state-of-the-art methods, which is important for studying the mechanics of near-fault processes. I follow this with some recent examples of surface rupturing earthquakes where high resolution optical data has revealed new information on the surface rupture. Since surface ruptures are intimately linked with earthquake rupture dynamics, we begin to look at how high resolution optical data can start to inform our understanding of the physics governing how faults slip.

• Speaker: James Hollingsworth, ISTerre, Grenoble, France
• Wednesday 21 May 2025, 14:00-15:00
• Venue: Wolfson Lecture Theatre.
• Series: Bullard Laboratories Wednesday Seminars; organiser: Adriano Gualandi.

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Self-organisation in plutonic igneous rocks has been suggested to form by a variety of mechanisms including oscillatory nucleation and growth, competitive particle growth (CPG), recrystallisation during compaction, and by a reduction in the total grain boundary energy budget based on the assumption that the energy of boundaries between two grains of the same mineral is less than that between two grains of different minerals. These various mechanisms can be distinguished on the basis of their microstructural signatures. An investigation of the Stillwater inch-scale layering and similar layers in the Bushveld intrusion shows that the CPG patterning mechanism leaves a characteristic microstructural record preserving evidence for slow super- and sub-solidus cooling with a highly interconnected texturally equilibrated melt phase that enhanced Ostwald ripening. The Skaergaard intrusion locally preserves cm-scale micro-rhythmic layering, superimposed on single modally-graded layers. The microstructures in the Skaergaard example do not show evidence of CPG . Furthermore, the energy of all relevant hetero-phase interfaces is less than that of the associated grain boundaries in igneous and metamorphic rocks, there is no compelling evidence for compaction in the Skaergaard intrusion, and the supposition of micro-rhythmic layering on modally graded layers formed by sedimentation precludes patterning by oscillatory nucleation and growth. A new patterning mechanism is proposed, whereby immiscible conjugate silicate liquids in the crystal mush self-organise, due to differences in their wetting properties in the compositionally-graded mush and the positive feedback due to the fact that the two immiscible conjugates predominantly crystallise the minerals which they preferentially wet.

• Speaker: Marian Holness, University of Cambridge
• Tuesday 13 May 2025, 12:00-13:00
• Venue: Department of Earth Sciences, Tilley Lecture Theatre.
• Series: Department of Earth Sciences Seminars (downtown); organiser: Dr Rachael Rhodes.

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Abstract not available

• Speaker: Prof Ljiljana Fruk ( Department of Chemical Engineering and Biotechnology)
• Thursday 22 May 2025, 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.

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