I18-Microfocus Spectroscopy
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Ivan N.
Pidchenko
,
John N.
Christensen
,
Martin
Kutzschbach
,
Konstantin
Ignatyev
,
Ignasi
Puigdomenech
,
Eva-Lena
Tullborg
,
Nick M. W.
Roberts
,
E. Troy
Rasbury
,
Paul
Northrup
,
Ryan
Tappero
,
Kristina O.
Kvashnina
,
Thorsten
Schäfer
,
Yohey
Suzuki
,
Henrik
Drake
Diamond Proposal Number(s):
[28254]
Open Access
Abstract: Uptake of uranium (U) by secondary minerals, such as carbonates and iron (Fe)-sulfides, that occur ubiquitously on Earth, may be substantial in deep anoxic environments compared to surficial settings due to different environment-specific conditions. Yet, knowledge of U reductive removal pathways and related fractionation between 238U and 235U isotopes in deep anoxic groundwater systems remain elusive. Here we show bacteria-driven degradation of organic constituents that influences formation of sulfidic species facilitating reduction of geochemically mobile U(VI) with subsequent trapping of U(IV) by calcite and Fe-sulfides. The isotopic signatures recorded for U and Ca in fracture water and calcite samples provide additional insights on U(VI) reduction behaviour and calcite growth rate. The removal efficiency of U from groundwater reaching 75% in borehole sections in fractured granite, and selective U accumulation in secondary minerals in exceedingly U-deficient groundwater shows the potential of these widespread mineralogical sinks for U in deep anoxic environments.
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Apr 2023
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[15947]
Open Access
Abstract: The alteration of olivine-rich rocks to serpentine minerals, (hydr)oxides, and aqueous hydrogen through serpentinization is long thought to have influenced the distribution of habitable environments on early Mars and the evolution of the early Martian hydrosphere and atmosphere. Nevertheless, the planetary importance of Martian serpentinization has remained a matter of debate. To constrain the process and products of Martian serpentinization, we studied serpentinized iron-rich olivines from the 1.1-billion-year Duluth Complex. These data indicate that serpentinized iron-rich olivine would have been accompanied by a fivefold increase in hydrogen production relative to serpentinized terrestrial mantle peridotites. In contrast to previous expectations, this style of serpentinization yields hisingerite as the dominant iron serpentine mineral at comparatively low temperature and pH, consistent with meteorite mineralogy and in situ rover data. The widespread occurrence of oxidized iron-bearing phyllosilicates in highly magnetized regions of the Martian crust supports the hypothesis that serpentinization was more pervasive on early Mars than currently estimated.
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Feb 2023
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I08-Scanning X-ray Microscopy beamline (SXM)
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Christina L.
Davis
,
Ryan A.
Venturelli
,
Alexander B.
Michaud
,
Jon R.
Hawkings
,
Amanda M.
Achberger
,
Trista J.
Vick-Majors
,
Brad E.
Rosenheim
,
John E.
Dore
,
August
Steigmeyer
,
Joel D.
Barker
,
Liane G.
Benning
,
Matthew R.
Siegfried
,
John C.
Priscu
,
Brent C.
Christner
,
Carlo
Barbante
,
Mark
Bowling
,
Justin
Burnett
,
Timothy
Campbell
,
Billy
Collins
,
Cindy
Dean
,
Dennis
Duling
,
Helen A.
Fricker
,
Alan
Gagnon
,
Christopher
Gardner
,
Dar
Gibson
,
Chloe
Gustafson
,
David
Harwood
,
Jonas
Kalin
,
Kathy
Kasic
,
Ok-Sun
Kim
,
Edwin
Krula
,
Amy
Leventer
,
Wei
Li
,
W. Berry
Lyons
,
Patrick
Mcgill
,
James
Mcmanis
,
David
Mcpike
,
Anatoly
Mironov
,
Molly
Patterson
,
Graham
Roberts
,
James
Rot
,
Cathy
Trainor
,
Martyn
Tranter
,
John
Winans
,
Bob
Zook
,
Mark L.
Skidmore
Diamond Proposal Number(s):
[25828]
Open Access
Abstract: Ice streams that flow into Ross Ice Shelf are underlain by water-saturated sediments, a dynamic hydrological system, and subglacial lakes that intermittently discharge water downstream across grounding zones of West Antarctic Ice Sheet (WAIS). A 2.06 m composite sediment profile was recently recovered from Mercer Subglacial Lake, a 15 m deep water cavity beneath a 1087 m thick portion of the Mercer Ice Stream. We examined microbial abundances, used 16S rRNA gene amplicon sequencing to assess community structures, and characterized extracellular polymeric substances (EPS) associated with distinct lithologic units in the sediments. Bacterial and archaeal communities in the surficial sediments are more abundant and diverse, with significantly different compositions from those found deeper in the sediment column. The most abundant taxa are related to chemolithoautotrophs capable of oxidizing reduced nitrogen, sulfur, and iron compounds with oxygen, nitrate, or iron. Concentrations of dissolved methane and total organic carbon together with water content in the sediments are the strongest predictors of taxon and community composition. δ¹³C values for EPS (−25 to −30‰) are consistent with the primary source of carbon for biosynthesis originating from legacy marine organic matter. Comparison of communities to those in lake sediments under an adjacent ice stream (Whillans Subglacial Lake) and near its grounding zone provide seminal evidence for a subglacial metacommunity that is biogeochemically and evolutionarily linked through ice sheet dynamics and the transport of microbes, water, and sediments beneath WAIS.
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Jan 2023
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I14-Hard X-ray Nanoprobe
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Takaaki
Noguchi
,
Toru
Matsumoto
,
Akira
Miyake
,
Yohei
Igami
,
Mitsutaka
Haruta
,
Hikaru
Saito
,
Satoshi
Hata
,
Yusuke
Seto
,
Masaaki
Miyahara
,
Naotaka
Tomioka
,
Hope A.
Ishii
,
John P.
Bradley
,
Kenta K.
Ohtaki
,
Elena
Dobrică
,
Hugues
Leroux
,
Corentin
Le Guillou
,
Damien
Jacob
,
Francisco
De La Peña
,
Sylvain
Laforet
,
Maya
Marinova
,
Falko
Langenhorst
,
Dennis
Harries
,
Pierre
Beck
,
Thi H. V.
Phan
,
Rolando
Rebois
,
Neyda M.
Abreu
,
Jennifer
Gray
,
Thomas
Zega
,
Pierre-M.
Zanetta
,
Michelle S.
Thompson
,
Rhonda
Stroud
,
Kate
Burgess
,
Brittany A.
Cymes
,
John C.
Bridges
,
Leon
Hicks
,
Martin R.
Lee
,
Luke
Daly
,
Phil A.
Bland
,
Michael E.
Zolensky
,
David R.
Frank
,
James
Martinez
,
Akira
Tsuchiyama
,
Masahiro
Yasutake
,
Junya
Matsuno
,
Shota
Okumura
,
Itaru
Mitsukawa
,
Kentaro
Uesugi
,
Masayuki
Uesugi
,
Akihisa
Takeuchi
,
Mingqi
Sun
,
Satomi
Enju
,
Aki
Takigawa
,
Tatsuhiro
Michikami
,
Tomoki
Nakamura
,
Megumi
Matsumoto
,
Yusuke
Nakauchi
,
Masanao
Abe
,
Masahiko
Arakawa
,
Atsushi
Fujii
,
Masahiko
Hayakawa
,
Naru
Hirata
,
Naoyuki
Hirata
,
Rie
Honda
,
Chikatoshi
Honda
,
Satoshi
Hosoda
,
Yu-Ichi
Iijima
,
Hitoshi
Ikeda
,
Masateru
Ishiguro
,
Yoshiaki
Ishihara
,
Takahiro
Iwata
,
Kousuke
Kawahara
,
Shota
Kikuchi
,
Kohei
Kitazato
,
Koji
Matsumoto
,
Moe
Matsuoka
,
Yuya
Mimasu
,
Akira
Miura
,
Tomokatsu
Morota
,
Satoru
Nakazawa
,
Noriyuki
Namiki
,
Hirotomo
Noda
,
Rina
Noguchi
,
Naoko
Ogawa
,
Kazunori
Ogawa
,
Tatsuaki
Okada
,
Chisato
Okamoto
,
Go
Ono
,
Masanobu
Ozaki
,
Takanao
Saiki
,
Naoya
Sakatani
,
Hirotaka
Sawada
,
Hiroki
Senshu
,
Yuri
Shimaki
,
Kei
Shirai
,
Seiji
Sugita
,
Yuto
Takei
,
Hiroshi
Takeuchi
,
Satoshi
Tanaka
,
Eri
Tatsumi
,
Fuyuto
Terui
,
Ryudo
Tsukizaki
,
Koji
Wada
,
Manabu
Yamada
,
Tetsuya
Yamada
,
Yukio
Yamamoto
,
Hajime
Yano
,
Yasuhiro
Yokota
,
Keisuke
Yoshihara
,
Makoto
Yoshikawa
,
Kent
Yoshikawa
,
Ryohta
Fukai
,
Shizuho
Furuya
,
Kentaro
Hatakeda
,
Tasuku
Hayashi
,
Yuya
Hitomi
,
Kazuya
Kumagai
,
Akiko
Miyazaki
,
Aiko
Nakato
,
Masahiro
Nishimura
,
Hiromichi
Soejima
,
Ayako I.
Suzuki
,
Tomohiro
Usui
,
Toru
Yada
,
Daiki
Yamamoto
,
Kasumi
Yogata
,
Miwa
Yoshitake
,
Harold C.
Connolly
,
Dante S.
Lauretta
,
Hisayoshi
Yurimoto
,
Kazuhide
Nagashima
,
Noriyuki
Kawasaki
,
Naoya
Sakamoto
,
Ryuji
Okazaki
,
Hikaru
Yabuta
,
Hiroshi
Naraoka
,
Kanako
Sakamoto
,
Shogo
Tachibana
,
Sei-Ichiro
Watanabe
,
Yuichi
Tsuda
Open Access
Abstract: Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss.
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Dec 2022
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[28784]
Open Access
Abstract: The local bonding environment of chlorine in silicate melts has a profound influence over the thermodynamic properties and structure of a melt, affecting the viscosity, rheology, and volatile degassing potential. To constrain the bonding environment of Cl in natural silicate melts, we have determined Cl K-edge X-ray absorption fine structure (XAFS) spectra for 44 experimentally produced silicate glasses in both the X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) regions. In the pre-edge region, the presence of a pre-edge peak indicates covalent bonding of chlorine with silicon. Addition of divalent cations suppresses this pre-edge feature, and its centroid shifts to higher energy, indicating a change to increasingly more ionic bonding. In the XANES region the main absorption edge energy, E0, and the energy of maximum intensity, EMax, are also compositionally dependent. SiO2- rich glasses have relatively low values of E0 and EMax while the addition of 2+ ions increases both to values close to those found in the end-member chlorides CaCl2, MgCl2, and FeCl2. In two Na-rich glasses, E0 and EMax are close to corresponding energies in NaCl. It appears, therefore that bonding in the glasses is closely related to that found in the simple chlorides. This may be due to clustering which generates Casingle bondCl, Mgsingle bondCl, Fesingle bondCl and Nasingle bondCl linkages either in the melts themselves or in the glasses due to rearrangements during quenching.
The EXAFS parts of the glass spectra confirm the conclusions derived from the XANES region. These show that, as expected from the XANES region, addition of Ca and Fe2+ leads to R-space peaks which are closely related to those found in anhydrous CaCl2 and FeCl2 respectively.
In order to determine if the spectra depend on pressure, temperature or chlorine fugacity of synthesis, 9 experiments were conducted using a single starting composition (Fe-free haplobasalt, An50Di28Fo22) across a range of temperatures (1300–1400 °C), pressures (5–20 kbar), chlorine fugacities (f(Cl2)) (1.38E−03 to 1.66E−06), and water contents (expected 0–8 wt% H2O). The results show that there is almost no change in the spectra across the XANES and EXAFS regions, indicating either that chlorine bonding is independent of the intensive parameters of the experiment or that all melts quench to glasses with the same local structure around the Cl atoms.
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Dec 2022
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B18-Core EXAFS
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Connaugh M.
Fallon
,
William R.
Bower
,
Brian A.
Powell
,
Francis R.
Livens
,
Ian C.
Lyon
,
Alana E.
Mcnulty
,
Kathryn
Peruski
,
J. Frederick W.
Mosselmans
,
Daniel I.
Kaplan
,
Daniel
Grolimund
,
Peter
Warnicke
,
Dario
Ferreira-Sanchez
,
Marja Siitari
Kauppi
,
Gianni F.
Vettese
,
Samuel
Shaw
,
Katherine
Morris
,
Gareth T. W.
Law
Diamond Proposal Number(s):
[16611, 16939, 17243]
Open Access
Abstract: Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1–2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.
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Dec 2022
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B07-C-Versatile Soft X-ray beamline: Ambient Pressure XPS and NEXAFS
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Diamond Proposal Number(s):
[28470]
Abstract: The chemical structures of aluminosilicate hydrates presented in alkali-activated geopolymer materials underpin their performances. Mg-substituted sodium aluminosilicate hydrates (N(-M)-A-S-H) are likely to be present in alkali-activated geopolymer materials prepared using MgO-containing precursors, however, their atomic-level structures remain unclear. The lack of such knowledge made it challenging to identify and distinguish N(-M)-A-S-H from complex alkali-activated geopolymer systems (i.e., alkali-activated slag, alkali-activated Mg-rich minerals), and therefore brought challenges in understanding and predicting their durability. This study characterised for the first time the atomic structures of the synthetic N(-M)-A-S-H gels, prepared through ion-exchange or co-synthesis, using X-ray absorption near-edge spectroscopy (XANES) at Si, Al and Mg K-edge. The results suggest that the substitution of Mg in the extra-framework locations of the alkali aluminosilicate hydrates (N-A-S-H) leads to negligible changes in the coordination environments of the aluminosilicate framework. However, the Mg coordination environment is distinguishably different from other Mg-containing phases in the systems, e.g., hydrotalcite. The Mg K-edge XANES of N(-M)-A-S-H shows a 0.8–1.2 eV shift compared with hydrotalcite. The results presented in this study can be used as the fingerprint to probe the presence of N(-M)-A-S-H in alkali-activated geopolymer materials containing Mg element.
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Nov 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[26730]
Open Access
Abstract: Hydrogen can act as an energy store to balance supply and demand in the renewable energy sector. Hydrogen storage in subsurface porous media could deliver high storage capacities but the volume of recoverable hydrogen is unknown. We imaged the displacement and capillary trapping of hydrogen by brine in a Clashach sandstone core at 2–7 MPa pore fluid pressure using X-ray computed microtomography. Hydrogen saturation obtained during drainage at capillary numbers of <10−7 was ∼50% of the pore volume and independent of the pore fluid pressure. Hydrogen recovery during secondary imbibition at a capillary number of 2.4 × 10−6 systematically decreased with pressure, with 80%, 78% and 57% of the initial hydrogen recovered at 2, 5 and 7 MPa, respectively. Injection of brine at increasing capillary numbers up to 9.4 × 10−6 increased hydrogen recovery. Based on these results, we recommend more shallow, lower pressure sites for future hydrogen storage operations in porous media.
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Nov 2022
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[21441, 24074]
Open Access
Abstract: Over 60 years of nuclear activity have resulted in a global legacy of contaminated land and radioactive waste. Uranium (U) is a significant component of this legacy and is present in radioactive wastes and at many contaminated sites. U-incorporated iron (oxyhydr)oxides may provide a long-term barrier to U migration in the environment. However, reductive dissolution of iron (oxyhydr)oxides can occur on reaction with aqueous sulfide (sulfidation), a common environmental species, due to the microbial reduction of sulfate. In this work, U(VI)–goethite was initially reacted with aqueous sulfide, followed by a reoxidation reaction, to further understand the long-term fate of U species under fluctuating environmental conditions. Over the first day of sulfidation, a transient release of aqueous U was observed, likely due to intermediate uranyl(VI)–persulfide species. Despite this, overall U was retained in the solid phase, with the formation of nanocrystalline U(IV)O2 in the sulfidized system along with a persistent U(V) component. On reoxidation, U was associated with an iron (oxyhydr)oxide phase either as an adsorbed uranyl (approximately 65%) or an incorporated U (35%) species. These findings support the overarching concept of iron (oxyhydr)oxides acting as a barrier to U migration in the environment, even under fluctuating redox conditions.
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Nov 2022
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I08-Scanning X-ray Microscopy beamline (SXM)
I18-Microfocus Spectroscopy
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Agnieszka
Dybowska
,
Paul
Schofield
,
Laura
Newsome
,
Richard
Herrington
,
Julian F. W.
Mosselmans
,
Burkhard
Kaulich
,
Majid
Kazemian
,
Tohru
Araki
,
Thomas J.
Skiggs
,
Jens
Kruger
,
Anne
Oxley
,
Rachel L.
Norman
,
Jonathan R.
Lloyd
Diamond Proposal Number(s):
[14882, 14908, 17882]
Open Access
Abstract: The Piauí laterite (NE Brazil) was initially evaluated for Ni but also contains economic concentrations of Co. Our investigations aimed to characterise the Co enrichment within the deposit; by understanding the mineralogy we can better design mineral processing to target Co recovery. The laterite is heterogeneous on the mineralogical and lithological scale differing from the classic schematic profiles of nickel laterites, and while there is a clear transition from saprolite to more ferruginous units, the deposit also contains lateral and vertical variations that are associated with both the original intrusive complex and also the nature of fluid flow, redox cycling and fluctuating groundwater tables. The deposit is well described by the following six mineralogical and geochemical units: SAPFE, a clay bearing ferruginous saprolite; SAPSILFE, a silica dominated ferruginous saprolite; SAPMG, a green magnesium rich chlorite dominated saprolite; SAPAL, a white-green high aluminium, low magnesium saprolite; saprock, a serpentine and chlorite dominated saprolite and the serpentinite protolith. Not all of these units are ‘ore bearing’. Ni is concentrated in a range of nickeliferous phyllosilicates (0.1–25 wt%) including serpentines, talc and pimelite, goethite (up to 9 wt%), magnetite (2.8–14 wt%) and Mn oxy-hydroxides (0.35–19 wt%). Lower levels of Ni are present in ilmenites, chromites, chlorite and distinct small horizons of nickeliferous silica (up to 3 wt% Ni). With respect to Co, the only significant chemical correlation is with Mn, and Mn oxy-hydroxides contain up to 14 wt% Co. Cobalt is only present in goethite when Mn is also present, and these goethite grains contain an average of 0.19 wt% Co (up to a maximum of 0.65 wt%). The other main Co bearing minerals are magnetite (0.41–1.89 wt%), chlorite (up to 0.45 wt%) and ilmenite (up to 0.35 wt%). Chemically there are three types of Mn oxy-hydroxide, asbolane, asbolane-lithiophorite intermediates and romanechite. Spatially resolved X-ray absorption spectroscopy analysis suggests that the Co is present primarily as octahedrally bound Co3+ substituted directly into the MnO6 layers of the asbolane-lithiophorite intermediates. However significant levels of Co2+ are evident within the asbolane-lithiophorite intermediates, structurally bound along with Ni in the interlayer between successive MnO6 layers. The laterite microbial community contains prokaryotes and few fungi, with the highest abundance and diversity closest to ground level. Microorganisms capable of metal redox cycling were identified to be present, but microcosm experiments of different horizons within the deposit demonstrated that stimulated biogeochemical cycling did not contribute to Co mobilisation. Correlations between Co and Mn are likely to be a relic of parent rock weathering rather than due to biogeochemical processes; a conclusion that agrees well with the mineralogical associations.
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Oct 2022
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