Search Results

You searched for all publications:

with publication states 'Published (Approved)'

Search Again...

These results only include publications that have been reviewed and processed by Diamond Light Source. To also view papers that have not yet been processed click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

27 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I12-JEEP: Joint Engineering, Environmental and Processing	Synchrotron x‐ray diffraction for sealed Mars Sample Return sample tubes L. F. Adam , J. C. Bridges , C. C. Bedford , J. M. C. Holt , E. Rampe , M. Thorpe , K. Mason , R. C. Ewing Meteoritics & Planetary Science 2678 DOI: 10.1111/maps.14105 Diamond Proposal Number(s): [30591] Open Access Show Abstract ▼ Abstract: The joint NASA-ESA Mars sample return campaign aims to return up to 31 sample tubes containing drilled sedimentary and igneous cores and regolith. The titanium alloy tubes will initially still be sealed when they are retrieved. Several types of measurement will be carried out on sealed samples in the pre-basic characterization phase of scientific investigation. We show that powder x-ray diffraction (XRD) analysis can be successfully carried out on sealed samples using an x-ray source at the I12 beamline of Diamond Light Source synchrotron. Our experiment used an analog sample tube and a Martian regolith analog (Icelandic basaltic sand). The titanium walls of the tube analog give strong but few diffraction peaks, making identification of the major constituent mineral phases feasible. A more significant constraint on quantification of mineral phase abundances by this XRD technique is likely to be the grain size of the sample. This technique opens up the possibility of initial mineralogical analysis of samples returned from Jezero crater without opening the sample tubes and the potential changes to the sample that entails.	Dec 2023
E01-JEM ARM 200CF E02-JEM ARM 300CF	Mineralogy and petrology of fine‐grained samples recovered from the asteroid (162173) Ryugu 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 , Bahae-Eddine Mouloud , 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 , William A. Smith , Sam Mcfadzean , Pierre-Etienne Martin , Paul A. J. Bagot , Dennis Fougerouse , David W. Saxey , Steven Reddy , William D. A. Rickard , 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 , Satoru Nakazawa , Tatsuaki Okada , Takanao Saiki , Satoshi Tanaka , Fuyuto Terui , Makoto Yoshikawa , Akiko Miyazaki , Aiko Nakato , Masahiro Nishimura , Tomohiro Usui , Toru Yada , Hisayoshi Yurimoto , Kazuhide Nagashima , Noriyuki Kawasaki , Naoya Sakamotoa , Peter Hoppe , Ryuji Okazaki , Hikaru Yabuta , Hiroshi Naraoka , Kanako Sakamoto , Shogo Tachibana , Sei‐ichiro Watanabe , Yuichi Tsuda Meteoritics & Planetary Science 33 DOI: 10.1111/maps.14093 Diamond Proposal Number(s): [31953, 30752] Show Abstract ▼ Abstract: Samples returned from the carbonaceous asteroid (162173) Ryugu by the Hayabusa2 mission revealed that Ryugu is composed of materials consistent with CI chondrites and some types of space weathering. We report detailed mineralogy of the fine-grained Ryugu samples allocated to our “Sand” team and report additional space weathering features found on the grains. The dominant mineralogy is composed of a fine-grained mixture of Mg-rich saponite and serpentine, magnetite, pyrrhotite, pentlandite, dolomite, and Fe-bearing magnesite. These grains have mineralogy comparable to that of CI chondrites, showing severe aqueous alteration but lacking ferrihydrite and sulfate. These results are similar to previous works on large Ryugu grains. In addition to the major minerals, we also find many minerals that are rare or have not been reported among CI chondrites. Accessory minerals identified are hydroxyapatite, Mg-Na phosphate, olivine, low-Ca pyroxene, Mg-Al spinel, chromite, manganochromite, eskolaite, ilmenite, cubanite, polydymite, transjordanite, schreibersite, calcite, moissanite, and poorly crystalline phyllosilicate. We also show scanning transmission electron microscope and scanning electron microscope compositional maps and images of some space-weathered grains and severely heated and melted grains. Although our mineralogical results are consistent with that of millimeter-sized grains, the fine-grained fraction is best suited to investigate impact-induced space weathering.	Nov 2023
E01-JEM ARM 200CF E02-JEM ARM 300CF I14-Hard X-ray Nanoprobe I18-Microfocus Spectroscopy	Correlated multi-technique characterisation of sulfur-bearing serpentine in carbonaceous chondrites Niamh Topping , John C. Bridges , Leon J. Hicks , Takaaki Noguchi EGU General Assembly 2023 (EGU23) DOI: 10.5194/egusphere-egu23-6355 Open Access Show Abstract ▼ Abstract: Phyllosilicate minerals in the carbonaceous chondrites provide insights into processes in primitive parent bodies of the early Solar System. It is widely agreed that the CM- and CI-type carbonaceous chondrites underwent aqueous alteration on their parent bodies, resulting in phyllosilicate-rich matrices, where the dominant mineral phase is serpentine. There are many previous studies investigating phyllosilicate structure in carbonaceous chondrites, however, the presence of sulfur in these minerals and its effect on crystal lattice structure has not been studied in detail. We are investigating how the presence of sulfur (up to ≃9-10 wt% SO3) in serpentine phyllosilicate regions effects basal lattice spacing measurements of serpentine-like minerals in CM- and CI-type chondritic and related asteroidal material. Four specimens are being studied for this work: Winchcombe and Aguas Zarcas (CM-type), and Ryugu samples (A0058-C2001-08, A0104-00200502 and A0104-01700602) from Hayabusa2 and Ivuna (CI-type). All samples are TEM wafers. We have used a multi-technique approach to study the samples, with the E01 JEOL ARM200CF and E02 JEOL ARM300CF electron microscopes at the ePSIC facility at Diamond Light Source in Harwell, UK. EDS compositional data has been collected using the E01 microscope, whilst HRTEM and HAADF imaging data has been collected at E02. At E02 we are also applying a new 4D-STEM nano-diffraction technique in order to collect lattice spacing data to correlate with our other HRTEM results. Fe-K XANES analyses on Winchcombe and Ryugu have been carried out using the I18 microprobe and I14 hard x-ray nanoprobe respectively, also at Diamond Light Source, to constrain Fe3+/ΣFe. By combining these techniques we aim to better understand the physical and chemical structure of serpentine-like minerals in carbonaceous chondrites. Initial analyses have shown that sulfur presence in carbonaceous chondrite phyllosilicates reduces the basal lattice spacings of serpentine-like minerals. In these sulfur-bearing regions, we have been finding lattice spacings in the range ~0.60-0.74nm for the CM-type chondrites. For the CI-type, these range between ~0.65-0.76nm. Differences in the reduced lattice spacing ranges are likely related to the redox state of the sulfur. In Ryugu and other carbonaceous chondrites the sulfur appears reduced; its content in serpentine is low and we see FeS grains. Comparatively, in Winchcombe (and others) more of the sulfur seems to be in the serpentine structure. We can conclude that in serpentine-like minerals, the presence of sulfur appears to reduce basal lattice spacing values compared to the expected d-spacing value of 0.70nm for serpentine. Possible reasons for this include further investigations into the valency of the sulfur ions, the bonding environment within serpentine layers, and the location of sulfur in either the octa- or tetrahedral lattice sites.	Feb 2023
E01-JEM ARM 200CF	A comparative carbon XANES and EELS study of organic matter in the Ivuna CI chondrite Lukas Petera , Hitesh G. Changela , John C. Bridges , Yoko Kebukawa , Leon J. Hicks , Niamh Topping , Martin Ferus EGU General Assembly 2023 (EGU23) DOI: 10.5194/egusphere-egu23-14828 Open Access Show Abstract ▼ Abstract: An understanding the organic matter (OM) in primitive interplanetary materials can provide us with important constraints on both the early solar system carbon cycle and incipient prebiotic synthesis before the origin of life. As a window to the past, primitive chondrites preserve the most pristine record of parent body, nebular and interstellar components and the occurrence of OM in them has been shown in both soluble (SOM) (1) and insoluble (IOM) (2) form. Total organic carbon (TOC) abundance reaches ~3-4 wt% in the most primitive carbonaceous chondrite (CCs) (3), such as Ivuna-type chondrites (CIs) – thus making them highly desirable for the OM studies, and relevant to the study of Asteroid 162173 Ryugu samples from the Hayabusa-2 mission. A combination of both SOM and IOM analysis of organic bulk meteorite separates together with in-situ analysis of OM have provided a comprehensive account of chondritic OM (4). In the case of in-situ analysis, the combination of both scanning (SEM) and transmission electron microscopy (TEM) together with soft X-Ray scanning transmission microscopy (STXM) have shown the presence of micron to submicron distinctive organic particles (OPs) (5). Carbon K-edge X-ray absorption near edge structure (XANES) has shown the aromatic-carbonyl-carboxyl chemical nature of these organic particles (5). In addition, aromatic-poorer and carboxylic-richer diffuse OM (6) within both amorphous and phyllosilicate occurs as well. As observation techniques are getting better, aberration corrected TEM coupled with electron energy loss spectroscopy (EELS) might provide the same results as carbon XANES, but with higher image magnification, rapid data acquisition and better accessibility. In this context, we present the results of a comparative carbon K-edge XANES and EELS study of CI meteorite Ivuna. An approximately 100 nm lamella of the Ivuna meteorite was prepared using focused ion beam (FIB)-SEM with the Helios 5 Hydra DualBeam (CEITEC, Masaryk University, Czechia) and analysed by TEM-EELS with the JEOL ARM200CF (ePSIC, Diamond Light Source, UK) and STXM-XANES at Beamline BL19A of the KEK Photon Factory, Japan. We observed that (I) XANES on samples that did not experience TEM-EELS are in agreement with the previous studies of aromatic-carbonyl-carboxylic macromolecular OPs and IOM, while (II) the TEM-EELS of OPs show aromatic-carbonyl functional chemistry but with amorphous carbon convoluting the carboxylic peak, and aromatic-poor spectra with a sharp carbonate peak in diffuse OM. The difference between XANES and EELS particularly in the diffuse OM can be interpreted by electron-beam damage. Thickness and e-beam damage leads to amorphous C formation in the OPs. In the case of more labile OM in the phyllosilicate, its change by heating and oxidation is expected.	Feb 2023
I12-JEEP: Joint Engineering, Environmental and Processing	Synchrotron X-ray diffraction for early characterisation of sealed Mars2020 samples Lukas Adam , John Bridges , Donald Bowden , John Holt , Candice Bedford EGU General Assembly 2023 (EGU23) DOI: 10.5194/egusphere-egu23-14721 Open Access Show Abstract ▼ Abstract: NASA, ESA and the UK are collaborating on a Mars Sample Return (MSR) mission which aims to retrieve drill cores of Martian rock for terrestrial analysis, starting with the Mars2020 rover which landed successfully in Jezero Crater in Feb. 2021. Up to 30 samples, inside sealed titanium sample tubes, are planned to be returned to Earth in later missions. Due to the potential for back-contamination of Earth from possible extant life on Mars, strict contamination control measures must be taken for the purposes of planetary protection, as well as to prevent contamination of the samples by Earth’s environment. These measures place restrictions on the way measurements can be performed on the samples until they have been sterilised or judged safe. As the first step of scientific analysis, all samples will undergo a set of measurements called Pre-Basic Characterisation. Pre-BC will include weighing, X-ray CT, and magnetic measurements. These data along with Basic Characterisation data will be used to decide experimental plans for multi instrument analyses on the Mars samples. X-ray Diffraction (XRD) is currently planned for a later stage of sample analysis after the sample tubes have been opened due to limitations with conventional commercial X-ray diffractometers. [1, 2] While a conventional X-ray tube cannot provide an appropriate X-ray beam, a synchrotron source is capable of much higher intensities and precise wavelength selectivity. Synchrotron facilities also allow more suitable diffraction geometries for the size and shape of sample expected from MSR. We have carried out experiments with the help of Diamond Light Source’s I12-JEEP beamline to test the feasibility of XRD analysis of samples in sealed Mars2020 sample tubes and suitable instrument parameters for XRD of these samples. Titanium tubes were prepared as analogues to Mars2020 sample tubes. Three different geological analogues were used in place of the Mars samples: an Icelandic basaltic sand, a calcareous mudstone from Watchet Bay, UK, and a Devonian Fine Grained Sandstone, UK. Two different methods for preventing unwanted diffraction signal from the sample tube walls have also been tested: subtracting the diffraction spectrum of an empty tube from the tube-with-sample spectrum, and using energy-dispersive X-ray diffraction to exclude tube wall signal. We show that quantitative XRD phase analysis can be successfully carried out on returned Mars samples in unopened sample tubes using a synchrotron X-ray source, and thus could be included in the Pre-BC phase of returned sample science. This would provide mineralogical data much earlier in the sample science process, improving decision-making around sample science, curation, and handling.	Feb 2023
I14-Hard X-ray Nanoprobe	A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu 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 Nature Astronomy 121 DOI: 10.1038/s41550-022-01841-6 Open Access Show Abstract ▼ 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.	Dec 2022
I18-Microfocus Spectroscopy	The redistribution of sulphur in secondary minerals of Winchcombe and other CM chondrites John Bridges British Planetary Science Conference 2022 Diamond Proposal Number(s): [31641] Open Access Show Abstract ▼ Abstract: The rapidly recovered Winchcombe CM chondrite regolith breccia fall gives the opportunity to analyse the secondary alteration phases of this meteorite type in great detail, without the effects of terrestrial contamination. A key part of determining the record of parent body water-rock reactions is studying the mineralogy of phyllosilicates with SEM, (S)TEM-EDX and XAS to determine their structure and cation site occupancies including Fe2+/Fe3+. Linked to the secondary alteration and phyllosilicate mineralogy is the redistribution of sulphur, a process which has been linked to the extent of hydrous alteration [1]. Here we consider the identity and assemblages of secondary S-bearing phases - serpentines and tochilinite - in a polished section of Winchcombe in order to better understand the alteration histories of CM chondrites and the nature of their serpentine-like phases. We are also studying these phases of interest in a set of other fresh CM meteorites including the recent fall Aguas Zarcas. As part of the Winchcombe analytical team, we have analysed clast and matrix in the section P30543 [1] at the University of Leicester Advanced Microscopy Facility. An initial investigation identified various locations of interest for further FIB-TEM analysis and XAS. FIB lift-out sections measuring up to 15 × 8 µm were extracted using a FEI Quanta 200 3D FIB-SEM, and thinned to ~100 nm attached to TEM Cu-grids for TEM analysis. High-resolution TEM imaging and STEM EDX was performed using JEOL 2100 TEM’s. Fe K XANES and EXAFS were performed at Beamline I18 of Diamond Light Source on P30543 using the techniques described in [3,4] to quantify Fe3+/SFe. Although the hydrated sulphide tochilinite is present in small amounts as needle-like crystalline patches in this section, the dominant S-bearing low temperature phase is a S-bearing 1:1 structure serpentine. This can be distinguished from the tochilinite in composition, as tochilinite is ~43 wt% SO3 whereas the Sserpentine is typically ~6-10 wt% SO3. The S-bearing serpentine can in turn also be distinguished from Spoor serpentine in the same section by d001 spacings which are 0.62-0.70 and 0.70-0.74 nm respectively. The relatively scarce tochilinite has d-spacings of 0.54 nm. The S-poor and S-rich serpentine phases are both ferric, having Fe3+/SFe 0.5-0.75. In contrast the tochilinite is more ferrous. We are studying the relative abundances and textural characteristics of S-bearing serpentine compared to bona fide tochilinite in Winchcombe and other CM’s in order to provide fresh insights into the record of progressive waterrock reactions in their parent bodies. [1] Suttle M. et al. 2022 MAPS in prep. [2] Daly L. et al. 2022 MAPS in prep. [3] Hicks L. J. et al. (2020) MAPS 55, 2599–2618. [4] Piercy J.D., Bridges J.C. and Hicks L.J. (2022) GCA 326: 97-118.	Jun 2022
I14-Hard X-ray Nanoprobe I18-Microfocus Spectroscopy	Carbonate dissolution and replacement by odinite and saponite in the lafayette nakhlite: part of the CO2-CH4 cycle on Mars? J. D. Piercy , J. C. Bridges , L. J. Hicks Geochimica Et Cosmochimica Acta 192 DOI: 10.1016/j.gca.2022.02.003 Show Abstract ▼ Abstract: New mineralogical studies of Lafayette reveal that it contains a notably variable abundance of martian carbonate. Four percent was identified in mesostasis (3.2%) and olivine-hosted (0.8%) fractures in one polished section, but only 0.2% of both textural types in another. The Lafayette carbonates are Mg0.0-2.0Cc13.2-38.6Sd17.7-81.9Rh3.1-42.9. They have undergone variable but extensive amounts of dissolution and replacement as the nakhlite secondary fluid evolved, associated with the precipitation of ferric saponite in olivine fractures and a serpentine-like phyllosilicate in the mesostasis. The mesostasis carbonate has undergone the highest degree of corrosion and replacement. TEM analysis has shown the presence of Fe-(hydr)oxide (likely ferrihydrite) nanoparticles on olivine-hosted carbonates which can be linked to the cessation of more extensive carbonate dissolution at those sites. The mesostasis serpentine-like mineral has been described here on the basis of WDS and EDX analyses, HRTEM and Fe-K XANES, as odinite, a ferric, 0.7 nm d001-spacings phyllosilicate mineral with a characteristic 1:1 serpentine-like structure. The carbonate dissolution stage and then formation of Fe-(hydr)oxide nanoparticles occurred under circumneutral-alkaline conditions 7 < pH < 10. This range of pH is also where the general dissolution mechanism switched from a proton-promoted, to a water hydrolysis reaction associated with a reduction in the dissolution rates. As dissolution rates were reduced and the fluid had cooled to ≤50°C, the precipitation of the ferric saponite and odinite, a phyllosilicate associated with temperatures of ∼25°C, dominated over the carbonate dissolution. The extensive dissolution of such crustal carbonate across the upper martian crust, producing bicarbonate and carbon dioxide, and the coupled formation of ferric phyllosilicates, would lead to the formation of CH4 in substantial amounts via a Fischer-Tropsch type reaction. The results of our study illustrate a process to explain the relatively low abundance of detected carbonate on Mars and a likely source for some of the methane on Mars.	Feb 2022
E01-JEM ARM 200CF E02-JEM ARM 300CF I14-Hard X-ray Nanoprobe I18-Microfocus Spectroscopy	Fe‐redox changes in Itokawa space‐weathered rims L. J. Hicks , J. C. Bridges , T. Noguchi , A. Miyake , J. D. Piercy , S. H. Baker Meteoritics & Planetary Science 312 DOI: 10.1111/maps.13611 Diamond Proposal Number(s): [19641, 23232, 26303] Open Access Show Abstract ▼ Abstract: Synchrotron Fe‐K X‐ray absorption spectroscopy and transmission electron microscopy have been used to investigate the mineralogy and Fe‐redox variations in the space‐weathered (SW) rims of asteroidal samples. This study focuses on the FIB lift‐out sections from five Itokawa grains, returned by the Hayabusa spacecraft, including samples RB‐QD04‐0063, RB‐QD04‐0080, RB‐CV‐0011, RB‐CV‐0089, and RB‐CV‐0148. Each of the samples featured partially amorphized SW rims, caused by irradiation damage from implanted low mass solar wind ions, and the impacting of micrometeorites. Using bright‐field and HAADF‐STEM imaging, vesicular blistering and nanophase Fe metal (npFe0) particles were observed within grain rims, and solar flare tracks were observed in the substrate host grain, confirming the presence of SW zones. We use Fe‐K XANES mapping to investigate Fe‐redox changes between the host mineral and the SW zones. All SW zones measured show some increases in the ferric‐ferrous ratio (Fe3+/ΣFe) relative to their respective host grains, likely the result of the implanted solar wind H+ ions reacting with the segregated ferrous Fe in the surface material.	Jan 2021
E02-JEM ARM 300CF I14-Hard X-ray Nanoprobe	Fe-K XANES and HR-TEM analyses of Apollo lunar grain space weathered surfaces Leon Hicks , John Bridges , Takaaki Noguchi , Jack Piercy 14th Europlanet Science Congress 2020 DOI: 10.5194/epsc2020-715 Open Access Show Abstract ▼ Abstract: Space weathering due to the bombardment of electrons and solar wind upon the exposed lunar surface shows as an apparent spectral darkening and reddening in ground-based and lunar-orbital observations. Space weathered rims have been observed on soil surface samples, returned by the Apollo landings, featuring amorphized material and nanophase Fe metal (npFe⁰) particles formed due to the implantation of solar wind H⁺ ions reducing the host grain mineral oxides to form metal. Oxidation of these Fe particles has also been shown, and a suggested correlation between oxidation and lunar soil maturity.In this study, we investigate Fe-redox changes in the space weathered rims of Apollo 17 lunar surface soil samples, using TEM and X-ray nanoprobe Fe-K XANES.	Sep 2020

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User