I18-Microfocus Spectroscopy
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Ian T.
Burke
,
Patrizia
Onnis
,
Alex L.
Riley
,
Catherine J.
Gandy
,
Violeta
Ramos
,
Gavyn K.
Rollinson
,
Patrick
Byrne
,
Richard A.
Crane
,
Karen A.
Hudson-Edwards
,
Elin
Jennings
,
William M.
Mayes
,
J. Frederick W.
Mosselmans
,
Adam P.
Jarvis
Diamond Proposal Number(s):
[29808, 31675]
Open Access
Abstract: The erosion of legacy coastal municipal solid waste landfill sites will result in the dispersion of particulate material into nearby ecosystems with potential for effects on marine populations. Information on the speciation and solid phase associations of metal(loid) contaminants will help to predict contaminant behaviour and better understand ecosystem risks. Here, we investigate the solid phase composition of, and metal(loid) leaching from, fine fraction materials recovered from three actively eroding coastal landfill sites. High concentrations of a range of potentially toxic elements (As, Cd, Cr, Cu, Pb, Ni and Zn) were present in multiple samples, but metal(loid) leaching rates were very low (≪1 wt%) in both deionised water and seawater solutions. Therefore, particulate dispersion is the most likely mode of contaminant transport occurring at these sites. The fine fraction materials were dominated by fine sand sized (63–180 μm) quartz grains and silt sized (<63 μm) matrix components, which were likely to be poorly retained on beaches and easily transported offshore. Four priority contaminants (As, Cu, Pb and Zn) were found to occur primarily in adsorbed or precipitate forms, as either coatings on other particles or as discrete <10 μm particles. Dilution of these fine-grained contaminated particles within natural pelitic sediments will likely reduce the overall ecosystems impacts; but the risks to filter and bottom feeding organisms, and the potential for biomagnification across trophic levels are poorly understood.
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Oct 2025
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[9809]
Open Access
Abstract: Sublithospheric diamonds and their inclusions are the deepest known samples from the Earth's mantle. Typically, the inclusions are trapped as minerals which are only stable in the deep mantle, retrogressing into multiple phases during their uplift. Determining the bulk inclusion composition is difficult but crucially important. Here we use micron-scale synchrotron X-ray computed tomography alongside μ-Raman mapping to reconstruct primary inclusion compositions of seven former Ti-rich CaSi-perovskite inclusions, which had retrogressed to assemblages of breyite and perovskite. The inclusions display Ti#s (molar Ti/[Ti + Si]), ranging from 0.03 to 0.60. In diamonds with previously reported coexisting inclusions, former bridgmanite coexists with lower Ti# CaSi-perovskite and garnet inclusions with higher Ti# CaSi-perovskite. This observation is consistent with published petrological experiments on mafic compositions suggesting that CaSi-perovskite undergoes a decrease in Ti# after the post-garnet transition. Thus variations in Ti content of CaSi-perovskite inclusions are interpreted as differences in formation pressures.
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Jun 2025
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[23496]
Open Access
Abstract: Arsenic immobilization in soils and sediments is primarily controlled by its sorption onto or incorporation into reactive soil minerals, such as iron (oxyhydr)oxides. However, coexisting ions (e.g., dissolved bicarbonate, phosphate, silica, and organic matter) can negatively impact the interaction of the toxic arsenate species with iron (oxy)hydroxides. Of special note is inorganic phosphate, which is a strong competitor for sorption sites due to its analogous chemical and structural nature to inorganic arsenate. Much of our understanding of this competing nature between phosphate and arsenate focuses on the impact on mineral sorption capacities and kinetics. However, we know very little about how coexisting phosphate will alter the stability and transformation pathways of arsenate-bearing Fe (oxyhydr)oxides. In particular, the long-term fate and behavior regarding arsenate immobilization are unknown under anoxic conditions. Here, we document, through mineral transformation reactions, the immobilization of both phosphate (P) and arsenate [As(V)] in secondary mineral products and characterize their changing compositions during the transformations. We did this while controlling the initial P/As(V) ratios. Our results document that, in the absence or at low P/As(V) ratios, the initial ferrihydrite rapidly transforms to green rust sulfate (GRSO4), which further transforms into magnetite after 180 days. Meanwhile, high P/As(V) ratios resulted in a mixture of GRSO4 and vivianite, with magnetite as a minor fraction. Invariably, the speciation and partitioning of As(V) were also affected by the P/As(V) ratio. A higher P/As(V) ratio also led to a faster partial reduction of mineral-bound As(V) to As(III). The most important finding is that the initial ferrihydrite-bound As(V) became structurally incorporated into magnetite [low P/As(V) ratio] or vivianite [high P/As(V) ratio] and was thus immobilized and not labile. Overall, our results highlight the influence of coexisting phosphate in controlling the toxicity and mobility in anoxic, Fe2+-rich subsurface settings, such as contaminated aquifers.
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Jun 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Emily C.
Bamber
,
Margherita
Polacci
,
F.
Arzilli
,
Giuseppe
La Spina
,
Elisa
Biagioli
,
Jorge E.
Romero
,
Jean-Louis
Hazemann
,
Richard
Brooker
,
Robert
Atwood
,
Mike
Burton
Diamond Proposal Number(s):
[31529]
Open Access
Abstract: Investigating the textural properties and 3D geometry of the connected pore network in volcanic products provides insight into magma ascent processes, due to their influence on magma permeability, outgassing efficiency and explosivity. Here, we used X-ray computed microtomography to investigate vesicle textures in tephra from the 2021 Tajogaite eruption (La Palma, Spain) and the relationship between these pore network parameters and eruptive style. We report a 3D dataset of pore network parameters for lapilli clasts collected throughout the eruption, associated with different eruptive styles (ash-rich jets, lava fountains, Strombolian activity). In clasts from Strombolian activity, the lower vesicle number density (VND) and tortuosity factor (m) suggests that there are fewer vesicles and that the channels which connect them are less tortuous than in clasts from fountain and ash-rich jet activity, favouring a lower degree of gas–melt coupling and thus, more efficient outgassing. Instead, for clasts of lava fountain and ash-rich jet activity, the higher VND and m suggest a higher number of vesicles connected by more tortuous channels, promoting some degree of gas–melt coupling and thus, less efficient outgassing. However, in clasts from ash-rich jets, the presence of narrower channels, as suggested by the lower throat-pore size ratio, favours a greater degree of gas–melt coupling with respect to fountain activity, leading to magma fragmentation. This work highlights the importance of textural and pore network analyses in understanding eruption dynamics, and provides a case study for investigating the interplay between pore network parameters, magma permeability and ascent dynamics for low-viscosity magmas.
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Jun 2025
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I18-Microfocus Spectroscopy
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Clare L.
Thorpe
,
Nick
Aldred
,
Stuart
Creasey-Gray
,
Martin C.
Stennett
,
Eperke A.
Rencz
,
Susan
Nehzati
,
Latham T.
Haigh
,
Garry
Manifold
,
Nishta
Vallo
,
Christoph
Lenting
,
Claire L.
Corkhill
,
Russell J.
Hand
Diamond Proposal Number(s):
[38045]
Open Access
Abstract: Glass ingots of lead silicate composition from the shipwreck of the Albion were studied to ascertain the chemistry and mineralogy of alteration products after exposure to seawater for 220 years. Alteration observed on natural samples was compared to that of the same glasses exposed to short-term, high temperature, laboratory dissolution tests in synthetic seawater and significant differences were observed. Alteration layers on natural samples were more chemically complex having sequestered high concentrations of elements present only at trace quantities in seawater. Electron microprobe analysis and microfocus x-ray absorption spectroscopy shows that P, most likely released by biological activity in the vicinity of the wreck, accumulated in naturally altered samples to form Pb–Ca-phosphate phases whilst Pb-sulphate phases formed in laboratory tests. Meanwhile Fe, present at < 0.3 wt % in the glass and ppb concentrations in seawater, accumulated to form Fe-silicates whilst Mg-silicates predominated in laboratory tests. Biologically induced corrosion of naturally altered samples was also considered. Experiments conducted to test barnacle settlement rates suggest that biotoxic elements within the glass, primarily Pb but potentially also Cu, Co and Ni deterred barnacle settlement. Despite this toxicity, some colonisation of the glass surface by both barnacles and bryozoan did occur and, whilst barnacles appeared to protect against chemical attack, bryozoan colonies caused increased cracking, possibly due stress created at the glass surface. Results highlight the challenges in recreating open, natural systems in laboratory settings and demonstrate that elements present at low concentrations can have a significant impact over long timescales.
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May 2025
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[33049]
Open Access
Abstract: Risk management for agricultural use of digested sewage sludge requires better understanding of the behaviour and fate of contaminant metals in the plant root zone. A study employing rhizo-pot and plug-tray experiments was conducted to identify the zone near spring barley roots (Hordeum vulgare) where concentration and speciation of Cu and Zn are affected. Cu and Zn bonding environments in the root epidermis/cortex and vascular tissue were also identified. In the digested sludge-amended soil, spring barley absorbed Cu only from the immediate vicinity of the roots (<< 1 mm), but Zn was taken up from further afield (> 1 mm). In the rhizosphere Cu was predominately present as Cu(I) oxides or as Cu(II) absorbed/bonded to phosphate, whereas Zn was present as Zn(II) in inner-sphere complexes with metal oxide surfaces, as Zn(II) sulphides or Zn(II) bonded to/incorporated into carbonates. Cu taken-up by spring barley roots was largely sequestered in the root epidermis and/or cortex predominately in the coordination environments similar to those seen in the rhizosphere. Only a small proportion of the Cu was translocated into the vascular tissue (where it is in the same two bonding environments). Zn taken-up by spring barley roots was present as Zn(II) sulphides, Zn(II) absorbed to/incorporated into carbonates, or Zn(II)-organic complexes. Zn was readily translocated from roots to shoots. Better understanding of these differences in the mobility and uptake of Cu and Zn in sludge-amended agricultural soils could be used to undertake element specific risk assessments.
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May 2025
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I08-Scanning X-ray Microscopy beamline (SXM)
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Rhiannon L.
Jones
,
Jon R.
Hawkings
,
Michael P.
Meredith
,
Maeve C.
Lohan
,
Oliver W.
Moore
,
Robert M.
Sherrell
,
Jessica N.
Fitzsimmons
,
Majid
Kazemian
,
Tohru
Araki
,
Burkhard
Kaulich
,
Amber L.
Annett
Diamond Proposal Number(s):
[30572, 32502]
Open Access
Abstract: Iron is an essential micronutrient for phytoplankton and plays an integral role in the marine carbon cycle. The supply and bioavailability of iron are therefore important modulators of climate over glacial-interglacial cycles. Inputs of iron from the Antarctic continental shelf alleviate iron limitation in the Southern Ocean, driving hotspots of productivity. Glacial meltwater fluxes can deliver high volumes of particulate iron. Here, we show that glacier meltwater provides particles rich in iron(II) to the Antarctic shelf surface ocean. Particulate iron(II) is understood to be more bioavailable to phytoplankton, but less stable in oxic seawater, than iron(III). Using x-ray microscopy, we demonstrate co-occurrence of iron and organic carbon-rich phases, suggesting that organic carbon retards the oxidation of potentially-bioavailable iron(II) in oxic seawater. Accelerating meltwater fluxes may provide an increasingly important source of bioavailable iron(II)-rich particles to the Antarctic surface ocean, with implications for the Southern Ocean carbon pump and ecosystem productivity.
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May 2025
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[31591, 35606]
Open Access
Abstract: Despite being pivotal to the habitability of our planet, the process by which Earth gained its present-day hydrogen budget is unclear. Due to their isotopic similarity to terrestrial rocks across a range of elements, the meteorite group that is thought to best represent Earth's building blocks is the enstatite chondrites (ECs). Because of ECs' nominally anhydrous mineralogy, these building blocks have long been presumed to have supplied negligible hydrogen to the proto-Earth. However, recent bulk compositional measurements suggest that ECs may unexpectedly contain enough hydrogen to readily explain Earth's present-day water abundance. Together, these contradictory findings mean the contribution of ECs to Earth's hydrogen budget is currently unclear. As such, it is uncertain whether appreciable hydrogen is a systematic outcome of Earth's formation. Here, we explore the amount of hydrogen in ECs as well as the phase that may carry this element using sulfur X-ray absorption near edge structure (S-XANES) spectroscopy. We find that hydrogen bonded to sulfur is prevalent throughout the meteorite, with fine matrix containing on average almost 10 times more Hsingle bondS than chondrule mesostasis. Moreover, the concentration of the Hsingle bondS bond is linked to the abundance of micrometre-scale pyrrhotite (Fe1-xS, 0 < x < 0.125). This sulfide can sacrificially catalyse a reaction with H2 from the disk at high temperatures to create H2S, which could be dissolved in adjoining molten silicate-rich material. Upon rapid cooling, this assemblage would form pyrrhotite encased in submicron silicate-rich glass that carries trapped H2S. These findings indicate that hydrogen is present in ECs in higher concentrations than previously considered and could suggest that this element may have a systematic, rather than stochastic, origin on our planet.
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Apr 2025
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I14-Hard X-ray Nanoprobe
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Diamond Proposal Number(s):
[23602, 28688]
Open Access
Abstract: Coccolithophore microalgae intracellularly produce nanostructured calcitic platelets, known as coccoliths, through a biologically-controlled mineralization process. Mature coccoliths are secreted to the cell surface and assembled into a shell that envelops the cell. The large-scale global production of coccoliths, followed by their sedimentation to the ocean floor, significantly contributes to carbon cycling. Despite progress in understanding the biomineralization pathway of coccoliths, we are still limited in our ability to predict how future climate conditions will impact coccolith formation and thus ocean carbon fluxes. Investigating coccolith biomineralization at the single-cell level is therefore critical to advance our understanding but remains challenging since current imaging techniques lack the combined spatial and temporal resolution coupled with element-specific detection to follow processes in situ. In light of this gap, nanobeam-scanning X-ray fluorescence microscopy (nano-XRF) in the hard X-ray regime is employed here to investigate the intracellular elemental distribution of the coccolithophore Gephyrocapsa huxleyi (formerly Emiliania huxleyi) achieving a resolution of 100 nm and elemental detection from phosphorus (P) to zinc (Zn). Calcium- and phosphorus-rich intracellular bodies, previously proposed to be involved in coccolith biomineralization, were observed in cells initially prepared ex situ by drying. Interestingly, nano-XRF imaging reveals metal species (e.g., Mn, Fe, Zn) within these bodies that were not detected in earlier studies, suggesting multiple biological roles for these structures. Moving towards native-state imaging, G. huxleyi was then imaged in hydrated state using a dedicated liquid cell device. Measurements were performed on G. huxleyi cells both with and without coccolith shell in sea water medium and compared to those of dried cells, demonstrating comparable image quality. The future potential and limitations of liquid cell nano-XRF imaging for coccolithophores and other microorganisms are further discussed.
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Mar 2025
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I13-1-Coherence
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Emily C.
Bamber
,
Fabio
Arzilli
,
Giuseppe
La Spina
,
Margherita
Polacci
,
Silvia
Cipiccia
,
Darren J.
Batey
,
Lucia
Mancini
,
Mattia
De' Michieli Vitturi
,
Ali
Gholinia
,
Heath
Bagshaw
,
Danilo
Di Genova
,
Richard
Brooker
,
Daniele
Andronico
,
Rosa Anna
Corsaro
,
Daniele
Giordano
,
Pedro
Valdivia
,
Mike R.
Burton
Open Access
Abstract: The explosivity of a volcanic eruption is controlled by several interdependent processes during magma ascent, such as crystallisation, gas exsolution and outgassing. Syn-eruptive crystallisation can increase the potential of magma fragmentation. Whilst the degree of coupling between the gas and melt phases during ascent can influence eruptive style. Quantitative textural analysis of vesicles and crystals in erupted products can provide insight into syn-eruptive conduit processes and the conditions leading to magma fragmentation. Synchrotron-based imaging techniques such as X-ray computed micro-tomography can provide information on vesicle and crystal size, shape and their spatial distribution in 3D. Furthermore, X-ray ptychography, an X-ray microscopy technique with nanoscale resolution, can be used to expand this 3D textural analysis to nanoscale crystals in volcanic rocks.
Here, we present a 3D reconstruction and quantification of vesicle and crystal textures in pyroclasts of the Masaya Triple Layer eruption, a highly explosive Plinian eruption of Masaya caldera, Nicaragua. Images and observations of vesicle textures at the micro-scale were acquired using X-ray computed micro-tomography and used to reconstruct the geometrical properties of the connected pore network, including connectivity, tortuosity and the throat-pore size ratio. X-ray ptychography was used to perform a 3D textural analysis of nanoscale crystals within the groundmass of clasts. These data were used to reconstruct conduit processes and evaluate the impact of syn-eruptive crystallisation, vesiculation and outgassing on magma rheology and fragmentation. Our results provide insight into the driving mechanisms of highly explosive, basaltic Plinian activity, and also highlight the potential of using multi-scale 3D imaging techniques to analyse textural features in pyroclasts and investigate controls on eruptive style.
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Mar 2025
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