Category: TA Call 3

22-EPN3-054: Searching for Biosignatures in Extreme Environments – High-Altitude Andean lakes as Mars analogues

Visit by Fernando J. Gomez of CICTERRA (Argentina) to TA2 Facility 29 – Nano Secondary Ion Mass Spectrometer (South Korea) and TA2 Facility 34 – Atomic Level Electronic Structure STEM (South Korea).
Dates of visit: 04-15 September 2023

Report Summary: Microbial activity leaves fingerprints in the sedimentary record. Through its metabolism microbes catalyse reactions, thus recycling minerals, dissolved chemical species and gases. This produces changes in the isotopic and trace elements ratios and changes in crystal mineral fabrics, that can be preserved in the sedimentary record. This signals of biological activity, when differentiated from abiotically controlled processes, are known as biosignatures., and are a part of the toolbox of geobiological and astrobiological research. The main question here is how can textural and chemical biogenic signatures be clearly differentiated from abiotically mediated processes? The study of ancient deposits is problematic, in that primary signatures have likely been modified through changes in the chemical environment during diagenetic processes. In contrast, the investigation of modern analogues, where processes can be studied in situ and where secondary alteration is incipient to absent, can help to differentiate between biotically and abiotically controlled signatures in the sedimentary record.

In this study we explored the chemical isotope signature within microbially-related sedimentary carbonates, including: stromatolites, oncoids/pisoids and thrombolites. We focused on carbon isotopes in different microtextures to recognise isotope signatures at the micro-nano-scale with the aim of recognising chemically versus biologically precipitated minerals and organic components.

22-EPN3-015: Trace Element Partitioning Between (Mg,Ca)S and Highly Reduced Magmas – Implications for the Volatile Budget and Thermal Evolution of Mercury

Visit by Laurie Llado and Yishen Zhang of the University of Liege (Belgium) to TA2 Facility 21 – OU NanoSIMS 50L (UK).
Dates of visit: 31 July – 18 August 2022

Report Summary: Mercury’s magma ocean is thought to have contained abundant dissolved sulfur, which would have formed sulfides once the magma ocean reached sulfide saturation. Due to the low concentrations of Fe²⁺ in the silicate portion of Mercury and S speciation at low fO₂, it is likely that crystallisation of the magma ocean produced minerals of the MgS-CaS solid solution. In this study, we aim at calculating the U, Th, and K trace element partitioning between (Mg,Ca)S sulfides and their equilibrium silicate melt to better understand the thermal evolution of Mercury.

To this end, the U, Th, and K trace element compositions of ultra-small (Mg,Ca)S crystals (3-15 μm) produced in experiments performed under highly reduced conditions were measured using the Open University NanoSIMS (UK). Preliminary results shows that U and Th partition coefficients of MgCaS crystals are lower than U and Th partition coefficients in CaS and FeS. Further investigation is required to confirm these preliminary results and to determine more accurately the U, Th and K partition coefficients. Nevertheless, the acquired U/Mg and Th/Mg ratios and theirs related partition coefficients will be used to provide comprehensive knowledge about the thermal evolution of Mercury.

22-EPN3-036: Investigating Titanium and Chromium Isotopes in Unusual Achondrite NWA 8564

Visit by Julia Cartwright of University of Alabama (USA) to TA2.14 ETH Zurich Geo- and Cosmochemistry Isotope Facility (Switzerland).
Dates of visit: 10-22 July 2023

Report Summary: We pursued high-precision chromium (Cr) and titanium (Ti) isotopic analysis to better refine the parent body of little-studied unusual achondrite Northwest Africa (NWA) 8564. While originally classified as a cumulate eucrite, NWA 8564 displayed unusual lead (Pb) data, suggestive of contributions from an exotic component, thus calling into question its assumed parent body, asteroid 4-Vesta. In this work, we sampled, prepared, and dissolved materials from NWA 8564, eucrites Juvinas and Tirhert, alongside diogenite NWA 7831 and a terrestrial standard to determine the parentage of NWA 8564.

Samples were selected, sampled and sent to ETHZ to be crushed and taken through dissolution and column chemistry. As Cr and Ti isotope analysis require different schedules, the chemistry and analysis stages were staggered for efficiency (e.g., three Ti columns and the first stages of Cr column cleaning were performed prior to Ti arrival). During the visit, the Cr separation procedure was carried out and preliminary analyses were performed after the visit. Eluted Ti aliquots were assessed for content and subsequently diluted for MC-ICP-MS analysis in week 1. Following data assessment/reduction, further aliquots were prepared through week 2, resulting in ~4 sessions of Ti data. The preliminary results show Ti and Cr isotope values for NWA 8564 within the range of eucrites. This suggests that NWA 8564 originates from Vesta, and must have experienced a significant event on Vesta that affected the Pb isotope data. This may include remelting associated with a large impact, potentially linked to the large, ancient basins at Vesta’s south pole.

22-EPN3-059: Electron Impact Induced Emission of Formamide – Excitation Processes Study

Visit by Frantisek Krcma, Brno University of Technology (Czechia), to TA2 Facility 13 – Electron Induced Fluorescence Laboratory (Slovakia).
Dates of visit: 06-15 November 2023

Report summary: The main goals of the 2023 visit were to study the electron impact emission cross sections, spectral features, and dissociation thresholds of formamide (CH₃NO) vapour. The expected products of CH₃NO – atomic hydrogen, CO, CN, CH, NH. The present experiments are part of a campaign to understand diagnostic electron-impact driven emission and ionisation of molecules present in astrophysical environments.

During the visit we first determined the experimental conditions especially the suitable range of molecular beam pressures low enough to ensure binary collisions with electrons but high enough to ensure reasonable signal-to-noise ratio. Then we performed spectral measurements at various wavelength regions and identified the basic spectral features. It was unusually difficult to determine
suitable experimental conditions due to unstable formamide vapour pressure in the system. During the visit we had to slightly modify the gas inlet system of the apparatus. Therefore, further experimental measurements will be performed later in cooperation with the Comenius University group.

22-EPN3-035: Survival of chondrites in humid climate (Germany & Europe)

Visit by Silke Merchel of University of Vienna (Austria) to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 03-09 June 2023.

Report Summary: The extraction of carbon from stony and iron meteorites for ¹⁴C/¹²C accelerator mass spectrometry was tested using a commercial LECO inductive furnace apparatus.

Extraction conditions and chemicals such as gases, fluxes (iron, titanium) were investigated for their influence on blank levels, cross-contamination and quantitative extraction. Further systematic investigations are still needed to find the ideal extraction conditions. Additionally, off-line, CO₂ cleaning from SOx seems to be mandatory for reliable results. Test measurements with the gas ion source of the 50 kV LEA system, are promising to overcome “dead” carbon addition to carbon released from 50-100 mg meteorite.

22-EPN3-027: Dust-Carbon-Climate Feedbacks Tested Through Detailed Independent Dating of Arctic Wind-Blown Dust Sequences on Greenland (Part 2 – Laboratory Analyses)

Visit by Thomas Stevens of Uppsala University (Sweden) to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 04 – 13 March 2023.

Report Summary: Over a 10 day visit to the TA facility a total of 67 (45 macrofossils and 22 bulk sediment samples) radiocarbon ages were obtained from loess samples taken around Kangerlussuaq in western Greenland. This represents the largest dataset on such sediments in Greenland, and complements our existing luminescence and radiocarbon analyses on similar or duplicate samples. The aim of the work is to develop reliable independent age models for loess accumulation in Greenland, and thereby allow analysis of past climate, permafrost and dust over the last c. 6-7 thousand years. In particular, our aim was to test the cause of the offsets between luminescence and radiocarbon dating uncovered in our previous work, which represents a significant obstacle to developing age models for Greenlandic loess.

The new data represent a significant step towards resolving this. A first outcome is that macrofossil dating in these sediments seems extremely problematic, with most yielding post bomb ages indicating significant modern carbon contamination. A second outcome is that the high and low temperature bulk carbon dating shows more promise, and reveals extremely young ages (last 150 yrs to post bomb) for the upper c. 15-20 cm of sediment in the profiles. This is reinforced by the luminescence data, and suggest extremely rapid recent accumulation and high dust storm activity in the region. Finally, we will use the new ages to derive robust age models for past climate reconstructions in west Greenland, an area currently undergoing rapid climate change.

22-EPN3-110: Clumped Isotope Thermometry of Travertines in the Tauern Window (European Alps) – Significance for Past Seismicity and Risk Assessment of the Brenner Base Tunnel

Visit by Diethard Sanders of the University of Innsbruck (Austria), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 06-10 November 2023.

Report summary: In the European Eastern Alps, travertines precipitated from springs with superambient temperature are very rare. Travertines show fabrics distinct from ambient-temperature
spring limestones. We had identified three fossil travertine deposits in the Navis Valley, a valley between 1005 m a.s.l. (debouch) and a watershed at ~2300–2600 m a.s.l. The travertines are located at different altitudes (1816 m, 1706 m, 1228 m), and consist of stacked laminae 1.5–4 mm thick of radial-fibrous calcite. In active travertines, such fabrics characterise crystallisation at ~15-25°C. The Navis fossil travertines post-date the Last Glacial Maximum, as shown by four U/Th ages between 10.95 ± 0.08 to 9.94 ± 0.09 ka BP 1950 AD.

Clumped isotope thermometry (Δ47-thermometry) indicates that the travertine of each location precipitated at superambient temperatures well-above the mean annual air temperature in the recharge area. The travertine-depositing waters probably rose along a steep-dipping fault system in the rock substrate, whereby the activation of these faults may have been related to seismic activity. In the subsurface of the study area, faults associated with highly mineralised warm waters were encountered also in excavation of the Brenner Base Tunnel. Our results provide the first quantitative approach with respect to formation temperature and numerical age to the rare travertine deposits of the Eastern Alps, and may alert geologists to identify this specific type of deposit as a ‘warning hint’ for potential episodes of active faulting. This is relevant to seismic hazard assessment of buildings such as the Brenner Base Tunnel.

Read the full scientific report, with kind permission from Simone Silvestro.

22-EPN3-098: VNIR Analyses on Mars Analogues Volcanic Products at Low Temperature – Investigating the Influence of Granulometry and Crystallinity

Visit by Maximiliano Fastelli and Marco Baroni of the University of Perugia (Italy) to TA2.8 CSS (Cold Surfaces Spectroscopy) at IPAG (France).
Dates of visit: 22 April – 03 May 2024

Report Summary: During this project funded through the Europlanet 2024 RI 3rd call, reflectance VIS-NIR spectra were collected at the CSS laboratory in Grenoble, France. Different temperatures were chosen to collect reflectance spectral data of 2 synthetic martian rocks analogues which were collected in the 1 – 4.8 μm range considering 3 different crystal-to-glass ratios and 3 different grain
sizes.

We synthesised two magmatic melts having chemical compositions relatable to Gusev and Gale crater, on Mars. For each composition, one glass and two samples with different crystallisation degrees were analysed. Moreover, the spectra of three different grain size ranges (30-75 μm; 75-106 μm;106-150 μm) for each composition were collected.

The different degrees of crystallisation affect first the type of identified absorption feature and secondly the slope of reflectance spectra with important and interesting changes. Increasing crystallinity causes slopes of spectra to gradually shift from positive for glasses towards flat-negative for crystalline material. On the other hand, grain size influences reflectance intensity and slope, as increasing grain size results in lower reflectance values and flatter slopes. No loss of characteristic spectral is observed with changing grain size.

These results provide further information on the spectral response of synthesised rock samples, especially for what concerns glass-bearing materials, that can be used for modelling of spectral information coming from rocky bodies in the Solar system, especially for Mars. The relationships that will be observed could be used by the European and international scientific community, to interpret spectra obtained by remote sensing and field investigations of volcanic terrains on rocky bodies in terms of i) rock composition, ii) magmatic evolution, iii) rheological properties/cooling rates of magmas and iv) possible geodynamic source.

22-EPN3-080: Chronology, Evolution of CAIs in Ordinary Chondrites

Visit by Francois Holtz of Leibniz University of Hanover (Germany) to TA2.9 Ion Probe Facility (IPF), CRPG (France)
Dates of visit: 02-09 February 2024

Report Summary: This study investigates naturally quenched and experimentally homogenised olivine-hosted melt inclusions (OLHMIs) from different geodynamic settings. Using SIMS analysis at CRPG, Nancy, we measured H₂O and CO₂ contents of OLHMIs from Loihi Seamount, Etna, and Klyuchevskoy volcanoes. Values were adjusted using natural and synthetic glass references to account for compositional effects. OLHMIs from Loihi seamount pillow lavas showed H₂O contents comparable to published data. Experimental heating led to significant H₂O loss over time, with near-complete loss after 5 hours. Additionally, we analysed OLHMIs from Etna volcano for Br contents, adjusting with calibration from low-Br Macquarie MORB glasses and high-Br synthetic basaltic glasses. Br analysis exhibited a linear calibration with high accuracy. OLHMIs from etnean FS tephra had relatively low Br contents, with a slightly elevated Br/Cl ratio compared to mantle values. These findings contribute to our understanding of volatile behaviour in magmatic systems and offer insights into volcanic processes.

22-EPN3-047: Vein networks in the Variscan foreland basins in western Europe

Visit by Jeroen van der Lubbe of the Vrije Universiteit (Netherlands) to TA2.9 Ion Probe Facility (IPF), CRPG (France)
Dates of visit: 13-17 November 2023

Report Summary: The primary objective of the proposed research is to investigate the mechanisms of fluid and trace metal transportation from the deeper orogen to the mid-upper crustal levels. These levels are particularly significant as they are known to host mineralisation, including metals that play a crucial role in facilitating the energy transition. In this research, an examination is conducted on samples of quartz veins originating from the High Ardennes Slate Belt in the Rursee region of Germany, as well as its equivalent in Almograve, Portugal. The objective is to establish limitations on the movement of fluids and elements within upper crustal settings. The presence of veins in our research among allochthonous terranes with a peri-Gondwanan affinity provides support for the hypothesis that these veins may have originated from the same sources during the Variscan orogeny.

This research is a component of the ITN FluidNET initiative, which seeks to comprehend the fluid mobility and elemental transport across various levels of the Earth’s crust, including the lower, middle, and upper sections. The current investigation is done on context of the doctoral study of Akbar Huseynov, who focusses on the fluid migration and vein formation in the upper crust. The FluidNET project aims to validate its overarching hypotheses by employing various isotopic techniques involving radiogenic and stable isotopes, examining trace element distributions within fluid inclusions, and conducting geochronological analysis of fluid inclusions. These methods enable the project to trace the migration of fluids across a range of scales, from nano- to kilometres. The primary objective of this study is to enhance our understanding about the transport fluxes of metals that are crucial to current energy transition. To do this, the research aims to integrate fluid transport across temporal and spatial dimensions via the use of analytical and numerical methodologies.

22-EPN3-043: Investigating Reflectance and Emissivity Spectra of Minerals and Analogs under Vacuum to Support Analyses of Lunar Spectra

Visit by Janice Bishop of the SETI Institute (USA) and Kierra Wilk of Brown University (USA) to TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory (Germany).
Dates of visit: 12-21 November 2023

Report Summary: Laboratory experiments were conducted to investigate H₂O and OH species in minerals under different environmental conditions in order to improve our understanding of hydrated
species (H₂O/OH) identified on the Moon through both the H₂O stretching bands near 3 μm and the H₂O bending vibrations near 6 μm.

We were able to run reflectance and emission spectra under vacuum and different temperatures at the DLR Planetary Spectroscopy Laboratory (PSL) for several lunar analogues, plus a couple of sulfate analogues for Mars and an ammonia clay analog for Ceres. Measuring both the 3 μm and 6 μm spectral features with the same instrument under the same conditions was very helpful for our lunar project because these have been characterised using different instruments under different conditions at the Moon.

The hydration features near 2.7-3 μm are observed in the Moon Mineralogy Mapper (M3) hyperspectral imaging data on board the Chandrayaan-1 orbiter and exhibit variations near 2.7 and 2.9 μm that could be consistent with changes in hydroxyl (OH) and molecular H2O species in the lunar regolith. The band observed near 6 μm in telescopic spectra of the Moon are only due to H₂O species and not to OH. We observed changes with increasing vacuum level and increasing temperature for both features at 3 and 6 μm for our lunar samples. We also observed changes in the Mars and Ceres analogs under vacuum and after heating. Obtaining these spectral measurements at the DLR-PSL provided essential data for our planetary science projects.

22-EPN3-118: Irradiation of Enceladus Ice Analogues by Simulating Saturn’s Plasma Environment

Visit by Grace Richards of the Open University (UK) to to TA2.12 Atomki-Queen’s University Ice Laboratory for Astrochemistry (Hungary).
Dates of visit: 19-24 April 2023

Report Summary: Enceladus orbits within Saturn’s magnetosphere, which contains cold plasma composed of water group ions such as O⁺, OH⁺, and H₂O⁺. Irradiation of Enceladus’ surface by this plasma can change the volatile composition of the ice.

This program of experiments aimed to characterise the extent to which the Enceladus surface material is weathered by Saturn’s radiation environment, by exposing ice analogues to the ECR ion source in the AQUILA ice chamber. Ices, composed of H₂O, CO₂, NH₃, and CH₄, and with a temperature of 70K, were irradiated using relevant water group ions of energies between 10 – 45 keV. They were monitored throughout the irradiation process using FTIR spectroscopy and Quadrupole Mass Spectrometry (QMS). Temperature Programmed Desorption (TPD) studies were also carried out to investigate the radiation products in the ices.

20-EPN3-012: Probing Microscopic Mechanisms Behind Ice Processing by Cosmic Rays

Visit by Alexei Ivlev of Max Planck Institute for Extraterrestrial Physics (MPE) (Germany) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 03-08 April 2024

Report Summary: The principal aim of the proposal was to conduct experimental studies of microscopic mechanisms controlling processing of astrophysical ices due to their bombardment by CRs. Specifically, based on indications obtained during our previous TA visit, we performed dedicated experiments on CO ices bombarded by protons with energies near and higher the electronic stopping power peak. The aim
was to investigate the scaling dependencies of the first radiolysis products with the stopping power,
and to compare those with the dependencies expected from existing radiolysis theories. We focused on studying accumulation of the first radiolysis products, such as C₂O, CO₂, C₃O, and C₃O₂, at low proton fluences, where they show a linear growth.

The measured results exhibit an excellent scaling with the stopping power, which unambiguously indicates that the previously assumed radiolysis mechanisms, assuming transport of radiolysis products in ice, cannot operate in our case. Instead, our results suggest that reactions in ice occur in situ, and are caused by a combination of secondary ionization and excitation processes triggered in ice by the ejected electrons. Ab initio studies of chemical reactions between CO and ionized or electronically excited C₃O₂ molecules will be carried out in order to identify possible routes of in situ C₃O formation.

22-EPN3-048: Evaluation of the initial 92Nb abundance in the inner Solar System

Visit by Makiko Haba, Tokyo Institute of Technology (Japan) to TA2.14 ETH Zurich Geo- and Cosmochemistry Isotope Facility (Switzerland).
Dates of visit: 02-15 August 2023

Report Summary: Evaluation of the heterogeneous distribution of short-lived 92Nb in the protoplanetary disk is mandatory to utilize the ⁹² Nb-⁹²Zr chronometer for dating planetary materials. A higher initial ⁹²Nb/⁹³Nb ratio has been reported for one meteorite that originate from the outer Solar System compared to meteorites from asteroid Vesta, which formed in the inner Solar System. The initial ⁹²Nb/⁹³Nb ratios determined at high precision from various types of meteorites are needed to comprehend the initial distribution of ⁹²Nb in the early Solar System. To evaluate the initial ⁹²Nb/⁹³Nb ratio in the inner Solar System, we conducted Zr isotopic measurements of rutiles separated from the Miles iron meteorite (IIE), whose parent body is considered to have formed inside Vesta in the protoplanetary disk.

During the Europlanet TA visit, the Zr isotopic compositions of five rutile fractions were analysed using a Neptune Plus MC-ICPMS. These rutile fractions with large variations in Nb/Zr ratios yielded ε⁹² Zr values from 0.19 ± 0.28 to 5.27 ± 0.21. The Nb-Zr data form a single, well defined isochron yielding a ⁹²Nb/⁹³Nb Nb ratio of (1.10 ± 0.07) × 10^-5 at the time of rutile formation. Using the absolute age of the Miles iron meteorite (4542.3 ± 4.0 Ma, Kirby et al., 2022) yields an ⁹²Nb/⁹³Nb ratio of (1.76 ± 0.12) × 10^-5 at CAI formation. This is consistent with the initial ⁹²Nb/⁹³Nb ratio in Vesta formation region ((1.66 ± 0.10) × 10^-5), suggesting that the initial ⁹²Nb/⁹³Nb ratio was homogeneous in the inner Solar System.

22-EPN3-30: An Isotopic Inventory of Mars Analogue Environments

Visit by Michael Christopher Macey of the Open University (UK), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 06-10 November 2023.

Report Summary: This study analysed the carbon, oxygen, sulfur, and nitrogen isotope profiles in physiochemically distinct analogue environments to establish how the viability of biologically induced isotope fractionation as a candidate biosignature. The analysis was performed on sediment samples collected from analogue environments proposed as appropriate analogues for Noachian-Hesperian waters requires environments (e.g., highly saline and sulfurous). Specifically, these environments were the Salt flats of Western Sahara, a hypersaline environment that contains sulfurous sediments below thick halite layers, the high-altitude lakes of the Argentinian Andes, which possess a chemistry like dilute, modelled martian water chemistries and are impacted by a low atmospheric pressure and large diurnal fluxes in temperature and UV, the salt pans of the Makadikadi basin, and hypersaline lakes in Spain.

The analysis identified varied isotopic signatures across locations suggestive of diverse environmental conditions in terms of their microbial community, geology and inputs to the environment. Key differences include: Positive ³⁴S ad low ¹³C values in the Botswanan sediments, aligning with the detection of oxic conditions, while negative values in Argentinian and Saharan samples indicate a contribution of dissimilatory sulfur metabolisms. Variation in ¹⁵N values between environments highlight previously detected variation in the presence and abundance of nitrogen-dependent metabolisms. The ¹⁸O values also strongly support the input of glacial water into the Argentinian lakes. The synthesis of this isotopic analysis with geochemical and microbiological datasets from these Mars analogue environments stands to provide crucial insight into their role as potential biosignatures.

22-EPN3-064: Investigating Oxygen Isotopes within Ca-Al-rich inclusions (CAIs) and Compound-Chondrule-CAI (CCCAIs) Populations within CM chondrites

Visit by Pierre-Etienne Martin and Luke Daly of the University of Glasgow (UK) to TA2.9 Ion Probe Facility (IPF), CRPG (France)
Dates of visit: 24-28 April 2023

Report Summary: Compound-chondrule-Calcium-Aluminium-rich Inclusions (CCCAIs) are rare occurrences within carbonaceous chondrites. They have been reported sporadically within most major groups (CO, CV, and CH) and only described four times within CM (Mighei-like) carbonaceous chondrites of various degrees of aqueous alteration, such as Aguas Zarcas (CM2; Martin & Lee, 2021) and Paris (CM2.7; Rubin, 2015). These objects have been described as CAIs enclosing chondrules or as chondrules enclosing CAIs. The existence of CCCAIs suggests that chondrules and CAIs interacted within high particle density environments in the protoplanetary disk prior to their incorporation into their mutual parent bodies.

In this study, we investigated two such objects within the Aguas Zarcas meteorite using oxygen isotope
analysis in order to characterize the CAI and chondrule components of the CCCAIs in comparison with CAIs and chondrules within the rest of the two Aguas Zarcas samples. Results show that the CAI and chondrule components of CCCAIs originate from the same O isotope reservoirs as their regular counterparts, suggesting that no isotopic exchange occurred between the two types of components, and that the components originate from the same O isotope reservoirs as the CAIs and chondrules of the meteorite breccia. An exception is the ‘Cicero’s’ chondrule part, which has a very primitive O isotope composition similar Amoeboid Olivine Aggregate (AOA). Due to the very primitive O isotope composition of AOAs, their formation is thought to have occurred in a near-solar environment. Further evidence is needed, but the existence of these objects can better our understanding of the evolution of the protoplanetary disk and provide a new way to study the chondrule forming environment(s).

22-EPN3-020: Implantation of Oxygen Ions in Titan’s Aerosol Analogues

Visit by Veronique Vuitton and Filip Matuszewski of Institut de Planetologie et d’Astrophysique de Grenoble (France) to to TA2.12 Atomki-Queen’s University Ice Laboratory for Astrochemistry (Hungary).
Dates of visit: 18-22 March 2024

Report Summary: In this TNA visit, we irradiated adenine, an aromatic molecule rich in nitrogen, with low energy oxygen ions. Our general objective was to investigate the effect on the spectral properties and composition of the samples and on the chemical composition of the molecules sputtered in the gas phase.

Films of a few hundred nanometers were prepared using the sublimation/condensation reactor installed on Atomki QUeens Ice Chamber for Laboratory Astrochemistry (AQUIILA). Adenine is commercially available as a powder and was vaporized under low pressure to condense back on MgF2 windows. We irradiated our samples with 10-20 keV OH_x⁺ ion beams generated by the Electron Cyclotron Resonance Ion Source (ECRIS).

During the irradiation, the spectral properties of the irradiated samples were tracked in situ by FTIR spectroscopy. The products released during the irradiation were tracked with the residual gas analyzer attached to the AQUIILA chamber.

Ex situ analyses of the irradiated samples are also planned to determine their chemical evolution, especially their degree of oxygenation. The elemental and isotopic compositions will be determined by isotope ratio mass spectrometry (ir-MS), with the main objective to obtain their O/C ratio. The molecular composition of the samples will be obtained through very high-resolution mass spectrometry (HRMS).

22-EPN3-010: The Cosmic Dust Flux Over Geological Time – How Extraterrestrial Signals Become Preserved in Earth’s Marine Rock Record

Visit by Martin D. Suttle of the Open University (UK) to TA2.10 Stable, Rare Gas and Radiogenic Isotope Facility at CRPG (France). Isabelle Mattia (Imperial College London) also took part in the visit, supported through other funding.
Dates of visit: 18 – 27 October 2023

Report Summary:

Fossil micrometeorites (MMs) recovered from sedimentary rocks are mostly <2mm-sized I-type cosmic spherules (CSs): iron-rich cosmic particles that have experienced high degrees of melting and oxidation during atmospheric entry. Since extraterrestrial ³He is implanted into cosmic dust by solar and cosmic rays in interplanetary space, fossil I-types could play a significant role as carriers of ³He in sedimentary archives. This project aimed to test this hypothesis by systematically examining the ³He/⁴He ratios of various types of MMs at different stages of preservation.

Measurements of He isotopes using the Helix SFT mass-spectrometer at CRPG, Nancy revealed variable 3He/4He values, with only 8 of the 36 measurements yielding results above the solar energetic particle (SEP) ratio of 2.17E-04  – most of these were, expectedly, scoriaceous Antarctic MMs which experienced the least atmospheric heating. Two urban CSs and a fossil I-type were also enriched in 3He, suggesting preservation of some implanted nobles gases, although rare, is possible for particles that have experienced high degrees of entry heating and/or alteration during diagenesis. A host chalk enriched in fossil I-types returned a low ratio of 1.00E-06, which could imply ³He may be preferentially removed by secondary fluids peculating within the lithifying sediment, or the source of cosmic dust was not sufficiently saturated in extraterrestrial 3He.The main conclusions from this work are that the ³He signal and the abundance of fossil (I-type) micrometeorites in Earth’s sedimentary rocks are uncoupled. This implies that these two proxies (³He and fossil micrometeorite abundance) record separate size distributions of the extraterrestrial dust flux.

22-EPN3-113: Isotopic constraints on deformation of olivine: a preliminary study on mantle peridotites from Mt. Melbourne, northern Victoria Land, Antarctica

Visit by Daeyeong Kim and Jung Hun Seo of the Korea Polar Research Institute (KOPRI, Korea) to TA2.10 Stable, Rare Gas and Radiogenic Isotope Facility at CRPG (France).
Dates of visit: 17 August – 06 September 2023

Report Summary: Microstructures of olivine-rich rocks record tectonic events in mantle, due to their diverse slip systems associated with the various deformation conditions. There have been, however, no time constraints on the slip systems that generate the microstructures of olivine. This study first investigates the temporal relationship of various microstructures of olivine based on the Re-Os geochronology of included sulphides. Mantle xenoliths of one lherzolite and two harzburgites were collected near Mt. Melbourne, northern Victoria Land, Antarctica, which suffered several tectonic events during the Proterozoic and Phanerozoic eons. Sulphide grains are texturally associated with olivine deformation fabrics in mantle rocks. The Re-Os isotopes of the 18 sulphide grains collected from the mantle xenoliths were analysed by using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and negative-ion thermal ionization mass spectrometry (TIMS) at CRPG Nancy, France.

The measured Os quantities are 0.9–4789.3 pg and Re quantities are 4.3–7.0 pg in the sulphides. ¹⁸⁷Os/¹⁸⁸Os in the sulphide are 0.1250–0.1298 for J04-A, 0.1130–0.1185 and 0.1286 for J04-B, and 0.1203–0.1216 for J04-D1. The corresponding depleted mantle ages (T_RD) are calculated to be 0.26–0.63 Ga for J04-A, 1.5–2.3 and 0.14 Ga for J04-B, and 1.1–1.3 Ga for J04-D1. The ages correspond to the tectonic evolution of suturing, subducting, and rifting events of the studied area, implying that the various structural events preserved in the mantle xenoliths can be temporally constrained by the sulphide Re-Os geochronology.