I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Fabio
Arzilli
,
Margherita
Polacci
,
Alessandro
Fabbrizio
,
Giuseppe
La Spina
,
Eleni
Michailidou
,
Elisa
Biagioli
,
Richard A.
Brooker
,
Jean-Louis
Hazemann
,
Robert C.
Atwood
,
Danilo
Di Genova
,
Sumith
Abeykoon
,
David A.
Neave
,
Renat R.
Almeev
,
Mike
Burton
Diamond Proposal Number(s):
[31529]
Open Access
Abstract: Crystallisation kinetics play a fundamental role in controlling conduit dynamics and eruptive style. The degree of superheating is critical in controlling crystallisation kinetics; however, its effect is still debated and has an unclear impact on eruption dynamics. Here, we investigate how superheating influences clinopyroxene nucleation in tephritic magmas from the 2021 Tajogaite eruption (La Palma, Spain) through both in situ and ex situ view experiments. Our findings show that superheating delays nucleation by dissolving pre-existing nuclei, thereby inhibiting crystallisation upon return to subliquidus conditions. Using a numerical model, we investigate how different nucleation delays resulting from different degrees of superheating affect magma ascent dynamics. Depending on the initial thermodynamic conditions and on the pre-eruptive history of magma, an increased nucleation delay can significantly reduce crystal content during ascent, lowering magma viscosity and affecting eruptive style. These findings highlight the critical role of pre-eruptive thermal histories in controlling eruptive style, and provide constraints for refining experimental protocols and numerical models, with direct implications for improving volcanic hazard assessment and eruption forecasting.
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Jun 2026
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I18-Microfocus Spectroscopy
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Open Access
Abstract: Understanding the impact of volcanic eruptions on climate over the last two millennia is essential to place current anthropogenic climate change into a long-term context. High-resolution proxy archives are crucial for this purpose, yet their availability decreases rapidly back in time. Besides ice cores, speleothems and corals, tree rings represent a uniquely valuable archive, providing records with annual resolution of past-climate change. Volcanic eruptions are among the most impactful natural forcings on Earth’s climate, through the injection of gaseous plumes into the atmosphere that can induce warming or cooling of the planet surface. While some of these impacts are well-known and studied, there are many older volcanic events whose details are unknown or uncertain, due to the lack of direct historical evidence.
Volcanic plumes transport volatile elements (e.g., S, Fe, Zn, Cu, Hg) that can be absorbed by trees and recorded in the yearly tree-ring layers. So far, dendrochemistry has been widely applied to assess anthropogenic pollution, but our research explores its potential as a novel proxy: by identifying chemical spikes of these elements in tree rings of known age, it may be possible to correlate them with known volcanic eruptions or identify previously unrecognized volcanic events. Here we present data obtained at Diamond synchrotron on tree rings from juniper (Juniperus communis) samples from Kevo, Finland, whose dendrochronological records extend back to the early Middle Ages. These measurements revealed distinct peaks in metal elements such as Zn and Cu, which are typically enriched in volcanic plumes and can be hosted in the wood as semi-nutrients. Some concentration peaks detected in the tree rings correspond to the ages of major Icelandic eruption from the lower Middle Ages.
These preliminary results suggest that dendrochemical analyses may provide a new archive of past volcanic activity. If validated, this approach could significantly improve reconstructions of volcanic eruptions of the past and corresponding climate variability over the last two millennia.
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Mar 2026
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I13-1-Coherence
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Emily C.
Bamber
,
Fabio
Arzilli
,
Silvia
Cipiccia
,
Darren J.
Batey
,
Giuseppe
La Spina
,
Margherita
Polacci
,
Ali
Gholinia
,
Heath
Bagshaw
,
Danilo
Di Genova
,
Richard
Brooker
,
Daniele
Giordano
,
Pedro
Valdivia
,
Mike
Burton
Open Access
Abstract: Nanoscale crystals, or ‘nanolites’, are becoming increasingly recognised in both experimental products and natural samples of volcanic eruptions, across a range of magma compositions and explosivity. Nanolites can increase magma viscosity and influence eruptive style, due to the rheological impact of the nanoparticle suspension, by inducing chemical and structural changes in the residual melt and by facilitating heterogeneous bubble nucleation. Due to their large surface area, nanolites are also prone to aggregation. However, their morphology, spatial distribution and interaction in 3D has not yet been investigated.
Here we present a 3D, nanometre-scale visualisation and quantification of nanolites within scoriae of highly explosive basaltic volcanic eruptions, obtained using X-ray ptychography, a nanoscale microscopy technique. We find that titanomagnetite nanolites aggregate, forming elongate, irregular structures in 3D. Compositional heterogeneities are also observed within the matrix glass, as extraction of Fe and Ti from the melt during nanolite crystallisation forms differentiated, Si-rich boundary layers surrounding nanolites with higher viscosity. We support our 3D nanoscale observations with images acquired using SEM and STEM, utilising multi-scale imaging methods to visualise nanolite crystallisation in basaltic magmas. We find that syn-eruptive nanolite crystallisation can increase magma viscosity through their aggregation and impact on the composition of the residual melt, increasing the potential of magma fragmentation during ascent. Our results provide insight into the nanoscale structure of volcanic products and also the driving mechanisms of highly explosive basaltic volcanic eruptions.
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Mar 2026
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[22517]
Open Access
Abstract: Catastrophic failure is the end result of progressive localisation of damage creating brittle failure on a variety of system scales in the Earth. However, the factors controlling this evolution, and the relationship between deformation and the resulting earthquake hazard, are not well constrained. Here we address the question of how to adapt operational controls in a strain-inducing laboratory experiment so as to minimize associated microseismicity. We simultaneously image the induced damage using x-rays at a synchrotron, and detect acoustic emissions which can be fed back to change operational controls on the experiment. We confirm that using continuous servo-control based on acoustic emission event rate not only slows down deformation compared to standard constant strain rate loading, but also suppresses events of all sizes, including extreme events. We develop a new model that explains this observation, based on the observed evolution of microstructural damage and the fracture mechanics of subcritical crack growth. The model is independently consistent with the observed stress history and acoustic emission statistics. Our results imply that including seismic event rate control may improve risk management of induced seismicity over a range of event magnitudes, if similar processes are relevant at larger scales.
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Jun 2025
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[24074, 21441]
Open Access
Abstract: Operations at uranium (U)-mining and nuclear facilities have left a global legacy of significant radionuclide contamination in groundwaters which must be managed to minimize environmental harm. Uranium groundwater contamination is present at several sites globally, including Oak Ridge National Laboratory and Hanford, USA and Sellafield nuclear site, UK. In situ phosphate biomineralisation offers a promising method for radionuclide (including 90Sr and U) remediation at these sites. Typically, phosphate-generating amendments are injected into the subsurface to sequester select radionuclides in groundwaters by precipitation of poorly soluble Ca-phosphate phases and subsequent adsorption and/or incorporation of radionuclides to these poorly soluble phases, a remediation route being explored for both U and 90Sr. In this study, we investigate the mechanisms of U-phosphate precipitation in two phosphate-generating amendments (Ca-citrate/Na-phosphate and glycerol phosphate) under conditions relevant to Sellafield, UK. Using aerobic batch sediment experiments, we show both Ca-citrate/Na-phosphate and glycerol phosphate amendments are effective at enhancing removal of U(VI) from representative groundwaters (from 94% to >97%). Aqueous geochemical data coupled to speciation modelling highlighted that precipitation of U(VI) phosphate phases was the likely mechanism of U(VI) removal from groundwaters. Further X-ray absorption spectroscopy (XAS) analysis of solids confirmed U was present as a highly insoluble uranyl orthophosphate-like phase after treatment with both Ca-citrate/Na-phosphate and glycerol phosphate amendments. These data provide underpinning information on U-phosphate remediation in Sellafield relevant conditions thus expanding the range of treatment options for radionuclide contaminated groundwaters and defining the transport and fate of U during phosphate biomineralisation.
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Feb 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Margherita
Polacci
,
Fabio
Arzilli
,
Giuseppe
La Spina
,
Jean-Louis
Hazemann
,
Richard A.
Brooker
,
Robert
Atwood
,
Sebastian
Marussi
,
Peter D.
Lee
,
Roy A.
Wogelius
,
Jonathan
Fellowes
,
Mike R.
Burton
Diamond Proposal Number(s):
[28538]
Open Access
Abstract: Transitions in eruptive style during volcanic eruptions strongly depend on how easily gas and magma decouple during ascent. Stronger gas-melt coupling favors highly explosive eruptions, whereas weaker coupling promotes lava fountaining and lava flows. The mechanisms producing these transitions are still poorly understood because of a lack of direct observations of bubble dynamics under natural magmatic conditions. Here, we combine x-ray radiography with a novel high-pressure/high-temperature apparatus to observe and quantify in real-time bubble growth and coalescence in basaltic magmas from 100 megapascals to surface. For low-viscosity magmas, bubbles coalesce and recover a spherical shape within 3 seconds, implying that, for lava fountaining activity, gas and melt remain coupled during the ascent up to the last hundred meters of the conduit. For higher-viscosity magmas, recovery times become longer, promoting connected bubble pathways. This apparatus opens frontiers in unraveling magmatic/volcanic processes, leading to improved hazard assessment and risk mitigation.
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Aug 2024
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I12-JEEP: Joint Engineering, Environmental and Processing
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Alexis
Cartwright-Taylor
,
Maria-Daphne
Mangriotis
,
Ian G.
Main
,
Ian B.
Butler
,
Florian
Fusseis
,
Martin
Ling
,
Edward
Andò
,
Andrew
Curtis
,
Andrew F.
Bell
,
Alyssa
Crippen
,
Roberto E.
Rizzo
,
Sina
Marti
,
Derek D. V.
Leung
,
Oxana V.
Magdysyuk
Diamond Proposal Number(s):
[22517]
Open Access
Abstract: Catastrophic failure in brittle, porous materials initiates when smaller-scale fractures localise along an emergent fault zone in a transition from stable crack growth to dynamic rupture. Due to the rapid nature of this critical transition, the precise micro-mechanisms involved are poorly understood and difficult to image directly. Here, we observe these micro-mechanisms directly by controlling the microcracking rate to slow down the transition in a unique rock deformation experiment that combines acoustic monitoring (sound) with contemporaneous in-situ x-ray imaging (vision) of the microstructure. We find seismic amplitude is not always correlated with local imaged strain; large local strain often occurs with small acoustic emissions, and vice versa. Local strain is predominantly aseismic, explained in part by grain/crack rotation along an emergent shear zone, and the shear fracture energy calculated from local dilation and shear strain on the fault is half of that inferred from the bulk deformation.
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Oct 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[16188]
Abstract: Studying how magma moves within Earth's crust can help us to predict when volcanic eruptions will occur, an early warning system that saves lives. Previous research has shown that basaltic magmas migrating upwards in dikes may become "frozen" in the crust, unable to contribute to an eruption. Liquid magma behaves as a Newtonian fluid, like water, its viscosity does not change when a force is applied. However, as magma cools, the formation of crystals affects magma mobility. Understanding this process is fundamental for determining the mobility of magmatic bodies and the hazards associated with the potential eruptibility of basaltic systems. In work recently published in Nature Communications, an international team of researchers has developed a new technique to investigate crystallisation and its effects on magma mobility. Their novel approach yielded insights into magma propagation and will also be useful to materials scientists.
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Aug 2022
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B22-Multimode InfraRed imaging And Microspectroscopy
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Abstract: Breadcrust bombs are pyroclasts displaying fractured, dense surfaces enveloping expanded interiors, and are associated with Vulcanian explosions. We document pyroclasts from the 2008–2009 CE eruption of Chaitén (Chile) that are internally as well as externally breadcrusted. The pyroclasts are cut by intersecting micrometer- to millimeter-thick tuffisites with dense glassy walls, which grade into strongly inflated pumiceous material. We find H2O diffusion gradients proximal to the breadcrusted surfaces, such that H2O is depleted from far-field magma (0.68 ± 0.04 wt%) into dense, fractured vein walls (0.2–0.3 wt%), indicating a spatial association between H2O mass transfer within the pyroclast interior and both suppressed vesiculation and breadcrusting. We experimentally confirm that diffusive H2O depletion suppresses bubble growth at shallow conduit conditions. Therefore, we interpret the breadcrust formation to be induced by H2O diffusion and the associated rise in viscosity rather than by cooling in the classical breadcrust-formation models. We posit that a “dehydration quench” is important as degassing continues to very low H2O contents in shallow-conduit magma that continues to vesiculate.
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Jun 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Fabio
Arzilli
,
Margherita
Polacci
,
Giuseppe
La Spina
,
Nolwenn
Le Gall
,
Edward W.
Llewellin
,
Richard A.
Brooker
,
Rafael
Torres-Orozco
,
Danilo
Di Genova
,
David A.
Neave
,
Margaret E.
Hartley
,
Heidy M.
Mader
,
Daniele
Giordano
,
Robert
Atwood
,
Peter D.
Lee
,
Florian
Heidelbach
,
Mike R.
Burton
Diamond Proposal Number(s):
[16188]
Open Access
Abstract: The majority of basaltic magmas stall in the Earth’s crust as a result of the rheological evolution caused by crystallization during transport. However, the relationships between crystallinity, rheology and eruptibility remain uncertain because it is difficult to observe dynamic magma crystallization in real time. Here, we present in-situ 4D data for crystal growth kinetics and the textural evolution of pyroxene during crystallization of trachybasaltic magmas in high-temperature experiments under water-saturated conditions at crustal pressures. We observe dendritic growth of pyroxene on initially euhedral cores, and a surprisingly rapid increase in crystal fraction and aspect ratio at undercooling ≥30 °C. Rapid dendritic crystallization favours a rheological transition from Newtonian to non-Newtonian behaviour within minutes. We use a numerical model to quantify the impact of rapid dendritic crystallization on basaltic dike propagation, and demonstrate its dramatic effect on magma mobility and eruptibility. Our results provide insights into the processes that control whether intrusions lead to eruption or not.
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Jun 2022
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