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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I15-Extreme Conditions
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Open Access
Abstract: Various icy moons, such as Europa and Ganymede, have thin oxygen atmospheres and exhibit spectral features attributed to oxygen held in their surface ices. The oxygen forms from the radiolysis of water. The interiors of these bodies are subject to high pressures and it is not known how deep into icy moons oxygen-bearing ices can penetrate, or the structures formed by the oxygen–water system at high pressure. Here, we show that oxygen hydrates are stable to 2.6 GPa, allowing them to penetrate deep into icy moons, both above and below proposed sub-surface liquid-water oceans. Similarities between oxygen and hydrogen hydrates indicate potentially enhanced recombination rates, transforming them back into water and offering a resolution to the discrepancy between predicted and measured radiolysis rates. In addition to the low-pressure CS-II clathrate, our results find three high-pressure phases in the oxygen–water system: an ST clathrate, a C0 hydrate, and a filled ice isomorphous with methane hydrate III. This shows a vast storage potential for molecular oxygen in icy moons and indicates that Europa could still be absorbing oxygen into its crustal ice.
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Apr 2025
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I15-Extreme Conditions
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Hannah A.
Shuttleworth
,
Mikhail A.
Kuzovnikov
,
Lewis J.
Conway
,
Huixin
Hu
,
Samuel
Gallego-Parra
,
Israel
Osmond
,
Tomas
Marqueno
,
Jinwei
Yan
,
Michael
Hanfland
,
Dominique
Laniel
,
Eugene
Gregoryanz
,
Andreas
Hermann
,
Miriam
Pena-Alvarez
,
Ross T.
Howie
Diamond Proposal Number(s):
[30698]
Open Access
Abstract: Carbon, nitrogen, and hydrogen are among the most abundant elements in the solar system, and our understanding of their interactions is fundamental to prebiotic chemistry. CH4 and N2 are the simplest archetypical molecules formed by these elements and are both markedly stable under extremes of pressure. Through a series of diamond anvil cell experiments supported by density functional theory calculations, we observe diverse compound formation and reactivity in the CH4-N2 binary system at high pressure. Above 7 GPa two concentration-dependent molecular compounds emerge, (CH4)5N2 and (CH4)7(N2)8, held together by weak van der Waals interactions. Strikingly, further compression at room temperature irreversibly breaks the N2 triple bond, inducing the dissociation of CH4 above 140 GPa, with the near-quenched samples revealing distinct spectroscopic signatures of strong covalently bonded C−N−H networks. High temperatures vastly reduce the required pressure to promote the reactivity between CH4 and N2, with NH3 forming together with longer-chain hydrocarbons at 14 GPa and 670 K, further decomposing into powdered diamond when temperatures exceed 1200 K. These results exemplify how pressure-driven chemistry can cause unexpected complexity in the most simple molecular precursors.
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Feb 2025
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Open Access
Abstract: The Chicxulub asteroid that ended the Cretaceous Era ∼66.05 million years ago caused a prolonged time of global darkness – the impact winter – leading to mass extinctions. Elements from the asteroid, including the platinum group elements (PGEs) osmium, iridium and platinum are known from the globally distributed boundary clay but their carrier elements have so far been unknown. We identify, for the first time in detail, the presence of these PGEs within Chicxulub impact spherules and importantly, we identify their carrier elements. We show through synchrotron Nano-XRF how these PGEs occur in nanostructures as un-ordered cube- and/or needle-like crystals co-localizing with both siderophile and chalcophile elements including Co, Ni, Cu, Zn, and Pb, derived from the asteroid. These crystals are set within a matrix of iron-rich calcium and silica glass revealing the mix of vaporized target rock and the asteroid. The results provide insights into the combination of elements present in the spherules, indicating formation of new minerals. We argue that the nano-shards of unreactive elements such as platinum, iridium and copper acted as nuclei for aerosol formation and potentially contributed to a prolonged impact winter with darkness and cooling leading to a profound and long-term climate change.
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Dec 2024
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I11-High Resolution Powder Diffraction
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Rachael
Hamp
,
Christoph G.
Salzmann
,
Zachary
Amato
,
Milz L.
Beaumont
,
Hannah E.
Chinnery
,
Peter
Fawdon
,
Thomas F.
Headen
,
Paul F.
Henry
,
Liam
Perera
,
Stephen P.
Thompson
,
Mark G.
Fox-Powell
Diamond Proposal Number(s):
[36314]
Open Access
Abstract: Sodium chloride (NaCl) plays an important role in geochemistry, biology, industry, and food production, and it is among the most common salts in the solar system. Here, we report the discovery of a metastable NaCl dihydrate formed through rapid freezing (101–102 K s–1) of a NaCl solution at ambient pressure. Using synchrotron X-ray and neutron powder diffraction, we show that it transforms irreversibly to hydrohalite and ice Ih above 190 K upon heating and propose it is structurally related to hydrohalite with a 3 × 1 × 3 supercell as its unit cell. Calorimetric analyses reveal that the new hydrate transforms to hydrohalite with a heat release of −3.47 ± 0.55 kJ mol–1. The identification of this new NaCl dihydrate on the surfaces of icy worlds such as the moons of Jupiter and Saturn could indicate regions of recent activity where subsurface brines have frozen rapidly, priority targets for upcoming planetary missions.
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Dec 2024
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Open Access
Abstract: In the 1970s, US President Richard Nixon offered moon samples returned by the Apollo 11 and Apollo 17 missions to the leaders of the nations of the World. In this study, we used a combination of advanced X-ray analysis methods, including microtomography, tomosynthesis and hyperspectral chemical mapping to carry out a non-destructive forensic investigation of the Dutch Apollo 11 Goodwill sample, normally on display at the Boerhaave museum in the Netherlands. These powerful methods were uniquely able to non-destructively interrogate the samples encased in plastic without contact, providing 3D images of sample textures and compositional analysis, to assess whether the results agree with archive data on Apollo 11 coarse-grained soil sample number 10085, and to provide new insights on their origins. Our forensic investigation asked the question: were the rocks in the Dutch display actually picked up on the surface of the moon by Neil Armstrong and Buzz Aldrin?
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Dec 2024
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I11-High Resolution Powder Diffraction
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Diamond Proposal Number(s):
[29721, 4715]
Open Access
Abstract: The effects of post-hydration heating over a broad range of temperatures are evident in many Mighei-like carbonaceous (CM) chondrites as a variety of mineral transitions. To better understand these processes and how a CM chondrite’s starting composition may have affected them, we experimentally heated two meteorites with different degrees of aqueous alteration, Allan Hills 83100 and Murchison, at 25 °C temperature steps from 200 °C to 950 °C and 300 °C to 750 °C, respectively. During heating, synchrotron in situ X-ray diffraction patterns were collected. With the exception of calcite decomposition and its products, most mineral transitions were unaffected by starting composition. Key observations include: (1) partial decomposition of tochilinite at 200 °C, which indicates that tochilinite breakdown might be a two-stage process due to its intergrown layers of brucite/amakinite and mackinawite; (2) the breakdown of serpentine occurring at 300 °C with transitional phases appearing at 525 °C and 575–600 °C, while secondary olivine formed at 600 °C; (3) cronstedtite decomposing faster than lizardite, (4) the formation of secondary enstatite at 750 °C, and (5) calcite decomposition temperature differing significantly between meteorites, occurring at 725 °C and 575 °C in ALH 83100 and Murchison, respectively. The results for calcite are likely controlled by differences in its microstructure and chemical composition, related to the meteorite’s impact history and degree of aqueous alteration. The difference in calcite decomposition temperature also explains the contrasts in the observed breakdown products, with clinopyroxene occurring in both meteorites, and oldhamite only in ALH 83100. Mineral transitions due to post-hydration heating have been characterized with a high resolution XRD method, enabling a better understanding of processes occurring on the parent asteroids of CM chondrites.
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Dec 2024
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I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[31420]
Open Access
Abstract: In-falling cosmic dust has left evidence of meteoritic polymer amide in stromatolites, both fossil and modern. In search of evidence for continued present day in-fall, sea foam was collected from two beaches in Rhode Island and subjected to Folch extraction to concentrate amphiphilic components in a chloroform water–methanol interphase layer. Hemoglycin polymer amide molecules previously characterized by MALDI mass spectrometry in meteorites and stromatolites were identified in sea foam either directly, or via their fragmentation patterns. Residual isotope enrichment pointed to an extra-terrestrial origin. The unique resiliency of sea foam may be due to the formation of extended hemoglycin lattices that stabilize its closed-cell structure and its lightness can potentially be explained by photolytic hydrogen production.
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Nov 2024
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B22-Multimode InfraRed imaging And Microspectroscopy
I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[31420, 32898, 37199]
Open Access
Abstract: Hemoglycin, a space polymer of glycine and iron, has been identified in the carbonaceous chondritic meteorites Allende, Acfer 086, Kaba, Sutter's Mill and Orgueil. Its core form has a mass of 1494 Da and is basically an antiparallel pair of polyglycine strands linked at each end by an iron atom. The polymer forms two- and three- dimensional lattices with an inter-vertex distance of 4.9 nm. Here the extraction technique for meteorites is applied to a 2.1 Gya fossil stromatolite to reveal the presence of hemoglycin by mass spectrometry. Intact ooids from a recent (3000 Ya) stromatolite exhibited the same visible hemoglycin fluorescence in response to x-rays as an intact crystal from the Orgueil meteorite. X-ray analysis confirmed the existence in ooids of an internal three-dimensional lattice of 4.9 nm inter-vertex spacing, matching the spacing of lattices in meteoritic crystals. FTIR measurements of acid-treated ooid and a Sutter's Mill meteoritic crystal both show the presence, via the splitting of the Amide I band, of an extended anti-parallel beta sheet structure. It seems probable that the copious in-fall of carbonaceous meteoritic material, from Archaean times onward, has left traces of hemoglycin in sedimentary carbonates and potentially has influenced ooid formation.
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Oct 2024
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DIAD-Dual Imaging and Diffraction Beamline
I11-High Resolution Powder Diffraction
I12-JEEP: Joint Engineering, Environmental and Processing
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Open Access
Abstract: The plumes of Enceladus contain a non-ice component that originates from aqueous processes occurring within the interior 1,2. The ocean of Enceladus is thought to be connected to the surface across a range of time scales. These processes range from the rapid eruption of cryovolcanic plumes to slow crustal convection on geological timescales3,4. In every case, the system will have a temperature and geochemical evolution as it freezes, with the history of evolution recorded in the sequence of mineral precipitation. Analogously to igneous and metamorphic petrology, we can explore the mineralogy and its context to reconstruct the history of that sample. Most importantly, for astrobiological investigations, the formation and cryo-petrological study of inorganic salts can be used to identify sites of recent exposure on the surface.
Synchrotron X-ray techniques allow fast, high-resolution probing of these systems with X-ray light. By exploring large, multi-component samples with multiple techniques, with variable temperature over time we can reveal many emergent processes that may not be predictable with simple phase diagrams.
We use a combination of synchrotron powder X-ray diffraction (PXRD) and X-ray microtomography (µCT) across multiple beamlines at Diamond Light Source (I11, I12 and DIAD). Using a multi-modal approach, we present an in-situ study of the low-temperature phase behaviour of Na-Cl-HCO3 fluids. We employ K11-DIAD (Dual Imaging and Diffraction) to carry out ‘image-guided diffraction’ on an Enceladus-type sample frozen in real-time. DIAD’s unique capabilities allow us not only to study microstructure down to 1 µm but also to carry out spatially resolved XRD and identify solid phases present.
We present, for the first time, the use of dual imaging and diffraction of a Na-Cl-CO₃ solution frozen in real time in 3 dimensions [Figure 1]. DIAD’s imaged guided diffraction provides spatially-resolved XRD, allowing us to probe different regions of our sample and identify the formation of Na2CO₃ hydrates. We show the influence of carbonate chemistry on the sequence of cryogenic precipitation and the development of complex microstructures. These results provide insights into crustal transport processes and will help with interpreting observational data from upcoming Galilean missions.
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Sep 2024
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