Volcanic eruptions are spectacular displays of nature’s incredible power, but they put local communities at risk. Approximately 800 million people worldwide live within 100 km of a volcano that is currently erupting or has the potential to erupt in the future. Our ability to mitigate their hazard relies on empirical analyses of monitoring data, with large uncertainties in estimating the probability of an eruption and its impact.

Forecasting the size, duration and hazards of eruptions requires a deep understanding of magma transport and storage and quantifying the timescales of the processes occurring beneath the surface. The relationship between these sub-surficial processes and geophysical and geochemical observations made at the surface is key to understand volcanoes behaviour.

The minerals within the rocks erupted during volcanic eruptions are an incredible archive of information. They act like a probe into the volcano’s interior, allowing us to decode its behaviour and inform volcanic hazards assessment. Drawing from examples of some of the most active volcanoes in the world – such as Popocatepetl and Colima in Mexico, and Stromboli and Etna in Italy – this talk will take you on a journey inside the volcano factory, exploring the hidden processes that drive eruptions.

Stromatolites are layered sedimentary structures formed under the influence of microbial communities and environmental factors. They constitute amongst the oldest known evidence of life on Earth – over 3.4 billion years old – and provide a unique fossil archive spanning nearly all of geological time. In this seminar, I will invite you on a journey through the Microbialite Collection of the Muséum national d’histoire naturelle (Paris), a unique archive to explore: • How do stromatolites record the oxygenation of Earth’s atmosphere and oceans? • What can they tell us about the diversity of ancient surface environments? • Are the rhythmic laminations driven by biological processes… or by climate cycles? • Do these layered structures truly reflect biological activity? • And how can AI help distinguish biogenic from abiotic laminated rocks? At the intersection of geochemistry, palaeontology, and astrobiology, my research seeks to improve our understanding of how life has shaped the sedimentary record; with implications that extend beyond Earth’s history to the search for life on other planets.

Turbidity currents, gravity-driven sediment-laden flows, govern material transport and shape underwater landscapes across diverse environments. While extensively studied in marine settings, their behaviour in freshwater systems remains underexplored. We present multi-temporal, multi-scale observations from the Aare Delta of Lake Brienz (Switzerland), combining Acoustic Doppler Current Profiler measurements with high-resolution repeated bathymetric surveys to capture turbidity currents and the resulting lake bottom changes. We document the upslope migration of a bedform triggered by a single flow event, demonstrating how discrete turbidity currents can rapidly reshape the channel floor. We further place these observations within a broader geomorphic context using a rare 125-year bathymetric time series. This longer-term perspective reveals how turbidity currents influence channel morphology over centennial scales. Together, our results highlight the value of lacustrine settings as accessible, scaled-down natural laboratories that bridge the observational gap between controlled experiments and deep-ocean canyons, offering new insights into turbidity-current processes.

This half-day event aims to introduce BSc, MSc, PhD students, and postdocs to the diverse career paths of active alumni from the Earth and Environmental Sciences programs. Guest speakers will share their experiences, present their respective fields, and discuss how studying geosciences and the environment prepares you for the workforce. Through engaging discussions and Q&A sessions, they will help guide you as you explore future career opportunities. Please note that BSc classes will be rescheduled to allow you to attend this event.

Organic matter is expected to be a key component of bodies formed in the outer regions of planetary systems. In the Solar System, measured moments of inertia, interpreted with equations of state for ices, silicates, and carbonaceous materials, suggest that organics may constitute a major fraction of the refractory interiors of several icy bodies (e.g., Reynard & Sotin, 2023; Delarue et al., 2026). Organics may therefore exert a first-order control on thermochemical evolution and volatile production—an idea that is particularly timely given the growing population of low-density exoplanets. The presentation will summarize recent work aiming at (i) predicting the occurrence of organic-rich volatile worlds from host-star elemental abundances, and (ii) quantifying the impact of carbon/organics on thermochemical evolution. On the occurrence side, stellar abundance patterns are used to identify systems in which the available refractory and volatile budgets favor carbon-rich/organic-rich condensates beyond the relevant condensation fronts. On the interior side, evolution is modeled by combining equations of state for ices, silicates and carbonaceous materials with kinetic descriptions of the transformation of a representative organic compound as a function of time and temperature. The kinetic scheme tracks the progressive loss of H and heteroatoms from the carbonaceous phase, the associated increase in residual carbon density toward graphite-like values, and the production of mobile volatiles. These processes feed back on the thermal history and set the time-dependent inventories of potentially releasable species. Model outputs are used to quantify expected volatile release for Titan-like bodies and carbon-rich exoplanets, and to contrast these outcomes with classical telluric and ice–silicate evolution pathways. Implications for JWST-era characterization of low-density planets, and for joint constraints from mass–radius measurements, stellar abundances, and interior evolution models, are discussed.

Abstract to be provided.

Marine calcifiers archive past ocean conditions in the chemical and isotopic composition of their calcium carbonate skeletons, providing essential quantitative constraints on Earth’s climate beyond the instrumental era. However, these ‘proxies’ are influenced not only by the environment but also by organism-specific ‘vital effects’ arising from poorly defined biomineralisation processes. Scleractinian coral skeletons serve as key archives of the surface and deep ocean climate from seasonal to millennial timescales, yet vital effects can manifest as large temporally variable inter- and intra-colony differences and geochemical offsets between species. These complications place a limit on the accuracy of climate reconstructions, particularly prior to the instrumental era. Despite recognition of vital effects for more than 70 years, their mechanistic origins remain poorly constrained because multiple processes operate simultaneously during skeletal formation.

Here, I will synthesise recent advances in the understanding of coral biomineralisation and discuss a new framework we proposed categorising vital effects into four types: Physiological, Mineralogical, Microstructural, and Growth. Collectively, these describe the factors influencing skeletal trace element chemistry and isotope composition, including: the source of the ions required for biomineralisation, their transport, and the carbonate chemistry within the calcifying fluid; possible metastable precursor phases and the rate of biomineral growth; microstructural heterogeneity; and macro-scale growth dynamics. This framework serves to demonstrate how more targeted experimentation and proxy calibration can explicitly address individual vital-effect processes. To this end, I will also discuss here our efforts evaluating the influence of amorphous phases, growth rate and microstructural heterogeneity on coral skeletal chemistry.

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a microanalytical technique that has driven major advances across the Earth sciences. It enables quantitative trace element and isotopic analysis of geomaterials at the ppm level across nearly the full mass range of the periodic table. This talk explores the opportunities opened up by LA-ICP-MS imaging, as well as the challenges involved in applying the method.

Uranium-lead (U-Pb) dating of calcite is challenging because calcite commonly contains very low uranium and high initial lead concentrations, yet it offers exciting possibilities for dating calcite veins in mountain belts, fossil-free ancient limestones, and ore-bearing vein systems. This talk demonstrates how a U-Pb image-mapping approach can overcome key limitations of the calcite U-Pb system, including low U concentrations and high initial Pb.

Pixels on a U-Pb age map can be pooled into “analyses” according to their elemental or isotopic ratio distributions, generating a spread of U-Pb data on concordia. Regions affected by detrital components or chemically distinct carbonate generations can then be excluded using user-defined regions of interest or chemical criteria. The approach also allows direct correlation with complementary microtextural datasets, including optical petrography, cathodoluminescence, Raman spectroscopy, and EBSD maps, and is readily extendable to other LA-ICP-(MS)-MS geochronological systems, including Rb-Sr dating of micas.

Applications from a range of geological settings will be presented, including the Carboniferous North Dublin Basin, where late Eocene LA-ICP-MS U-Pb ages from calcite veins linked to folding and flexural-slip deformation record far-field, N-directed shortening associated with the Alpine-Pyrenean orogenies, together with examples using beta-decay chronometers.