20-EPN2-114: Microbial Adaptation in the Hypersaline Environment of Sua Pan Evaporator Ponds in Botswana and Implications for Search for Life on Mars (Part 2 – Microbial Characterisation)

Visit by Claudia Pacelli of the Italian Space Agency (ASI) to TA2.19 Center for Microbial Life Detection, Medical University Graz (Austria).
Dates of visit: 06-10 November 2023

Report Summary: The search for life on other planets, first of all Mars, is necessary informed by terrestrial biology. Studies of microorganisms on Earth expanded the limits of life to such an extent that many environments on Earth, previously thought to be uninhabitable, were found to harbor life. Some of these environments overlap with extraterrestrial planetary environments in some physical and chemical conditions. Because they contain life on Earth, similar environments can sustain life elsewhere in the Universe.

On Earth, the distribution of hypersaline environment is largely reported and mainly in arid environments like deserts. Among them, the Makgadikgadi salt pans (which include the Nxai, Ntwetwe and Sua pans), located in north central Botswana are considered one of the largest in the world, where the salts concentration is up to 21% of NaCl. These conditions may be compared with those detected on Mars.

This Europlanet project will provide valuable information about the limit of life on Earth, identifying the habitable environment for microorganisms in Makgadikgadi Salt Pans similar to the evaporitic basins or playa described in different areas of the Martian surface, such as Arabia Terrae and Meridiani Planum. In addition, metagenomics results allow us to investigate the genomic traits involved in microbial adaptation to extreme conditions on Earth, which have implications for the prospect of life on other planets since it is possible that life as behaves as it happened in the Salt Pans on Earth. These data will expand our knowledge about the habitability of Mars and will support future robotic and Mars sample return missions.

20-EPN2-031: Determination of the Timing of the Final Deglaciation and the Depth of Subglacial Erosion Using In-Situ Produced Cosmogenic ¹⁴C in Combination with Existing Cosmogenic ¹⁰Be Data

Visit by Régis Braucher of Cerege CNRS-Aix-Marseille University (France) to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 12 – 16 December 2022.

Report Summary: Glacial landforms formed during the last deglaciation in several valleys of the Retezat Mts (Southern Carpathians) have been dated by in situ produced cosmogenic ¹⁰Be. A bias towards old exposure ages has hindered the age determination of the last deglaciation phases (Ruszkiczay-Rüdiger et al., 2021, Geomorphology, 107719).

The measurement of the concentrations of the short-lived in situ produced ¹⁴C concentrations in the framework of the TA visit enables us to estimate the true age of these landforms and also allows the quantification of the amount of inherited ¹⁰Be. This inherited nuclide inventory is used to estimate the depth of subglacial erosion during the last glacial phase, a parameter that was not yet quantified in the region yet. Sixteen quartz samples (mass: 4-5 g) were analysed in the framework of this project in the Isotoptech AMS Laboratory (Debrecen, HU). All samples gave a reliable C yield (between 40-10 ug/sample). A special Gas ion source interface (GIS) and accelerator mass spectrometer (AMS) coupling technique enabled us to quantify the ¹⁴C/¹²C ratio in the small sized CO₂ samples. AMS ¹⁴C sample preparation and analyses was controlled by reference material preparations and parallel analyses. The resulted ¹⁴C data (fractionModern) now can be used for a more realistic exposure age determination and estimation of the depth of subglacial erosion in the Retezat Mts. This is the first application of the ¹⁰Be-¹⁴C nuclide pair in Eastern Central Europe.

20-EPN2-095: Carbon Isotopic Fractionation and Quantification in Perennial Cave Ice

Visit by Artur Ionescu of the Babes-Bolyai University (Romania), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 27 November – 08 December 2023.

Report Summary: The aim of this project is to investigate the carbon isotopic variation in perennial cave ice in different phases, for the determination of fractionation processes and estimation of the carbon source (organic or inorganic). To do so, we aim of using two types of samples, the first from
extracted ice from perennial cave glacier and ice created in laboratory conditions. We measured δ¹³C in gases trapped as “bubbles” in the ice mainly CO₂, in dissolved carbon in the ice as HCO₃ and CO₃, and in the cryogenic cave carbonates.

Our hypothesis presumes that isotopic fractionation of carbon could shift an inorganic
signature towards a more organic one, thus making it difficult to assess the origin of carbon,
hence misinterpreting the origin.

In total 36 measurements have been performed on carbon-13. Our preliminary data on the
fractionation of carbon-13 show that during freezing the bubbles “concentrate” the light
isotopic ratios while the most enriched values were found in the cave carbonates. Thus
confirming our hypothesis. This is the first study that described isotopic values of carbon-13
in the different phases of the cave ice, however more laboratory experiments are needed to
better constrain the isotopic fractionation process.

22-EPN2-036: Chronology, Evolution of CAIs in Ordinary Chondrites

Visit by Ritesh Kumar Mishra of the Veer Kunwar Singh University, Ara, Bihar (India) to TA2.9 Ion Probe Facility (IPF), CRPG (France)
Dates of visit: 13-17 November 2023

Report Summary: The first forming Solar System solids are the refractory oxides and silicates of calcium, aluminium, titanium and magnesium which give them their eponymous name Calcium, Aluminium-rich Inclusions (CAIs). Only a few (~50), mostly very small (~20-50 microns) have been found in Ordinary chondrites. Our extensive search for large CAIs in ordinary chondrites resulted in finding about 10 CAIs in Semarkona (LL3.00), ALHA81251 (LL3.3), Chainpur (LL3.4). Three Oxygen isotopic (Δ¹⁷O) studies along with ²⁶Al-²⁶Mg short-lived now extinct chronology were carried in 4 CAIs and 2 Al-rich chondrules to decipher their genesis and provenance and make comparative analysis with the vast amount of previous data from the carbonaceous chondrites.

20-EPN2-068: Primitive Space Materials (PriSMa)

Visit by Chrysa Avdellidou of the Observatoire de la Cote d’Azur (France) to TA2.7 Light Gas Gun Laboratory, University of Kent (UK)
Dates of visit: 17-21 April 2023

Report summary: Simulants of surface materials for various small bodies were sourced, characterised and formed into blocks. These blocks were sent to the University of Kent and used as targets in their two-stage light gas gun. An extensive programme of 20 shots was carried out at speeds from 0.39 to 4.9 km/s. This covers a range from low speed impacts up to the mean speed of impacts in the asteroid belt (5 km/s). All targets were weighed and imaged before each shot. Post-shot, the resulting impact craters were all been imaged, and crater size and shape have been measured. Crater ejecta was also collected. More detailed analysis is underway. With the results so far, it is now possible to predict crater shape in the strength regime over a wide speed range for such bodies and estimate the volume of ejected material. This experimental campaign included novel impact experiments to study the contamination of primitive bodies surfaces by foreign material.

This programme was successful and is being used to interpret remote sensing data from previous and upcoming space missions, such as OSIRIS-REx and MMX.

20-EPN2-021: Construction of lunar mineral maps using NIR hyperspectral data in combination with GRS and/or LIBS data

Visit by Kyeong Ja Kim of the Korea Institute of Geoscience and Mineral Resources (Korea) to TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory (Germany).
Dates of visit: 16-27 October 2023

Report Summary: There were three objectives of the project:

1. Development of a Bayesian method for spectral unmixing of NIR hyperspectral image data acquired by the Moon Mineralogy Mapper (M³) instrument with Gamma Ray Spectrometer (GRS) and Laser Induced Breakdown Spectroscopy (LIBS) data
2. Construction of global and regional maps of the main minerals of the Moon which are constrained by the elemental abundances measured by GRS and/or LIBS
3. Ingestion of the obtained map product into a mobile Geographic Information System (GIS).

Objective (1) was investigated with spectral analysis of various terrestrial analog samples along with lunar simulants to characterise image data that respond to mineralogical features which are directly connected to the mineralogical features of the moon investigated by remote sensing spectral data, especially M³ by Chandrayaan-1. The data obtained at DLR will be characterised with M³ data to understand mineralogical features as well as data obtained from KPLO GRS (KGRS). This approach will
guide in understanding regional mineralogical identification and elemental information that guides in investigation of lunar geology and resource prospecting. Objective (2) has been investigated using global elemental maps derived from M3 and Lunar Prospector GRS data.

The mineral maps constructed so far can be updated once KGRS data become available. Objective (3) will be addressed shortly by importing the constructed mineral maps into the K-Mapper software running on mobile devices. This will be invaluable for future human missions and the lunar resources prospecting international campaign as part of the Artemis 3+ activities.

20-EPN2-111: Proton Radiolysis of Astrochemically Relevant Formamide Ices Using A Formal Statistical Experimental Design

Visit by Perry Hailey of the University of Kent (UK) to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 02-22 May 2022

Report Summary:

Formamide (NH₂CHO) is of astrobiological interest as it has been identified as a potential precursor to a wide variety of organic compounds essential to life, and many biochemical studies propose it is likely to play a crucial role in the context of the origin of life.  Formamide contains an amide functional group which is the principal building block necessary to form chains of amino acids and proteins. Furthermore, it has been identified as a key precursor of a large variety of prebiotic molecules and in the presence of an energy source, it promotes the synthesis of adenine, guanine, cytosine, and uracil, which are the four nucleobases of ribonucleic acid or RNA; it is also a precursor of carboxylic acids, amino acids, and sugars.  In summary, the chemical versatility of formamide can lead, under favorable conditions, to the synthesis of many molecules that are key constituents of living organisms.  Several studies report the prebiotic synthesis of nucleobases from formamide under relatively warm conditions (i.e. near or above room temperature), there are no reports on the formation of nucleobases from formamide in interstellar ices through the combination of irradiation at astrophysically relevant low temperatures and subsequent thermal processes.  A few laboratory based studies have explored formamide irradiation although with in a largely non-systematic manner, typically employing a change One Factor At a Time (OFAT) approach.  Additionally, scant attention has been paid to the refractory components from the irradiation which would likely reveal the complex chemistry that emerges.

To investigate the role of cosmic ray induced chemistry, the Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) was used and ice analogues were prepared in situ by depositing gases and Formamide onto ZnSe substrates at 20 K, where they were monitored in the solid-phase by Fourier Transform Infrared (FTIR) Spectroscopy and QMS monitoring of the gaseous emissions.  TPD studies will also be performed from 20 through to 200K and both QMS and FTIR data captured on a temporal basis to allow for univariate and multivariate post data analysis.  Refractory components were also be retained for post chiral/achiral analysis.

20-EPN2-075: Emissivity Measurements of Proposed Source Minerals for Venus Anomalous Regions

Visit by Erika Kohler, NASA Goddard Space Flight Centre (UK), to TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory (Germany).
Dates of visit: 1-15 December 2022

Report Summary: This study directly measured the emissivities of four Venus-mineral analogues at Venus relevant temperatures and reflectivity spectra pre- and post- heating. Mission and ground-based observations of Venus show several anomalous regions related to elevation, but the variations are unknown to be compositional or morphological in nature. The comparison of emissivity measurements from candidate minerals at Venus surface conditions and reflectivity measurements will demonstrate whether mineralogical composition can be identified in future Venus missions and will constrain the source of the Venus highland radar anomalies. The results of this study will maximise the return of previous and future Venus missions that take surface measurements by contributing to the database of Venus analogues being compiled at the Planetary Spectroscopy Laboratory.

20-EPN2-094: Miniature Wind Vanes on Mars – Extracting Wind Flow Properties From Close-up Images of Sand Grains

Visit by Sebastiaan de Vet and Andreas Zafiropoulosof TU Delft (Netherlands) to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 22-26 January 2024

Report summary: Aeolian sediments are ubiquitous at the surface of Mars where they are found in active sand dunes and lithified aeolian outcrops. These features form a geological record of past and present interactions between the surface and atmosphere of an evolving planet. A deeper understanding of their formation and context can be obtained by studying these deposits at the grain-scale level. From terrestrial studies, we known that airborne orientation of non-spherical grains due to long-axis streamlining to the wind flow is considered to occur almost instantaneously after entrainment grains by saltation. Grain orientation in sediment fabrics therefore harbours valuable information on near-surface wind flow and particle mobility. A key focus of this project was to establish how atmospheric pressure and above-threshold wind conditions modulate the observed grain orientation signal. Well-rounded aeolian sand for the wind tunnel experiments was collected from the active drift sand geotope at ‘Bedafse Bergen’, located in SE Netherlands.

At the Aarhus Wind Tunnel Facility, we performed several experiments under various atmospheric pressures from ambient sea-level conditions to Mars-analogue pressures. Close-up images were obtained from the sediment fabric after various runs at 120% and 150% above threshold conditions. A date pipeline has been developed and is being refined for processing of imagery and quantifying the grain orientation to ultimately disentangle effects of airborne streamlining of grains and impact randomisation at various wind speeds and atmospheric pressures.

20-EPN2-123: Controls on the Resuspension of Dusts of Different Mineral Composition in Air Flows

Visit by Merren Jones and Steve Covey-Crump of the University of Manchester (UK), to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 11-15 September 2023

Report summary: Mineral dusts in the atmosphere cause a wide variety of damage to aircraft engines resulting in significant economic cost to the engine manufacturers and airline operators. The nature of damage is dependent on the mineralogy of the dust, and so there is currently a major drive to understand the controls on the composition of atmospheric dusts. We are currently planning a field campaign in central Australia to sample airborne sands and dusts together with surficial deposits, and the present study was designed to inform our sampling strategy and to help constrain the interpretation of our anticipated findings.

We performed wind tunnel experiments to examine detachment thresholds of seven minerals with different density, grain shape, and surface properties. The particle size variation (50-500 μm) of the detachment threshold is well-described by existing semi-empirical models but highlights the need to incorporate shape and adhesion properties into these models. In a further set of experiments, we used a new suction sampler to collect sand and dust particles in transport through the full depth of the flow (175 mm) to examine dust emission from the surface of a sand bed under conditions where the sand particles are saltating, and vertical particle size and compositional sorting developed within and above the saltating layer of a polymineralic sand. Provisional results show a good correlation between collected sample mass and mass-flux estimated from a laser opacity system throughout the depth of flow, and show strong vertical particle size and compositional sorting.

20-EPN2-117: To the Root of a Problem – Exploring Mars’s Rootless Cones Based on the Geomorphometry of Icelandic Analogues

Sebastiaan de Vet (TU Delft, Netherlands) and Lonneke Roelofs (Utrecht University, Netherlands) to TA1.1 – Iceland Field Sites, MATIS
Dates of visit: 04-12 July 2022

Rootless cones are created by steam explosions when lava flows interact with local water sources. Consequently, these landscape features offer a unique palaeo-environmental insight into the conditions at the time of the eruption. Rootless cones have also been identified on planet Mars. The aim of this project was to identify geomorphological and morphometric characteristics of Icelandic rootless cones and use these insights to infer the formation conditions and palaeo-environmental significance of rootless cones on the planet Mars. While features on Mars can only be studied remotely through satellite data, this project leverages the accessibility of lcelandic analogues to study their morphologies and properties in fine details. The rootless cone groups in the Younger Laxa Lava are uniquely and specifically suited for this purpose; they offer a morphological variety along various gradients of lava-water interactions.

During the field project the team intended to map representative rootless cones in the Younger Laxa Lava in high-resolution during a drone-assisted photogrammetric survey and analyse high-resolution Digital Terrain Models to quantitatively compare rootless cones on lceland and Mars. However, logistical issues arising in the aviation industry during Summer 2022 resulted in a temporary loss of fieldwork gear. The project was thus refocussed to carry out a field campaign to collect representative pilot-dataset to meet parts of the initial goals and prepare for a future follow-up campaign.

Banner image: A rootless cone at Myvatn Lake, Iceland. Credit: Hansueli Krapf/CC BY-SA 3.0

20-EPN2-090 – A Search for Thiols Formation Pathways Under Space-Relevant Conditions

Visit by Zuzana Kaňuchová (Astronomical Institute of the Slovak Academy of Sciences, Slovakia) and Tom Field (Queen’s University Belfast, UK) TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 27 November – 8 December 2023

Report Summary: Despite being only the tenth most abundant element in space, sulfur is a component of several biomolecules, making it a key subject for astrochemistry studies. Sulfur containing molecules were observed in the solid phase on the surfaces of icy moons and in the icy mantles of interstellar grains. Despite the seemingly ubiquitous detection of sulfur-bearing species in space, the sulfur budget is still puzzling the scientific community. To address this, Zuzana Kaňuchová and Tom Field conducted an exploratory series of irradiation experiments to determine if species with thiol (-SH) groups may be formed in hydrocarbon-rich ices at temperatures relevant to interstellar matter, the surfaces of Solar System icy satellites, and Kuiper Belt objects.

They implanted 200 keV S+ ions in methane (CH4), ethane (C2H6), ethene (C₂H₄), and ethyne (C₂H₂) ices at 20 K and 60 K. Formation (and destruction) of species was monitored via FTIR spectroscopy and quadrupole mass spectrometry. Based on preliminary analysis performed during the TA they decided to conduct one extra (supplementary) experiment to explore the possibility of forming carbon and sulfur-bearing molecules by implanting high-energy carbon (750 keV) ions into hydrogen sulfide (H₂S).
The preliminary analysis does not indicate the formation of thiols in the investigated hydrocarbon ices as a result of high-energy sulfur ions implantation. However, several new absorption bands appeared in the
spectra of all irradiated hydrocarbons, indicating the formation of various alkanes and alkenes. The emergence of a prominent band around ~1600 cm-1 could suggest the presence of carbon in an amorphous form.

20-EPN2-116: HIDISCC (Hypervelocity Impacts for DISC Calibration)

Visit by Vincenzo Della Corte, Osservatorio Astronomico Capodimonte Napoli, INAF (Italy), to TA2.7 Light Gas Gun Laboratory, University of Kent (UK)
Dates of visit: 27-29 March 2023

Report summary: The Comet Interceptor space mission is to launch in 2029 to study a dynamically new comet. Two of the three spacecraft involved will host copies of the Dust Impact Sensor and Counter (DISC), which will measure the physical properties of cometary dust. The spacecraft’s velocity (7-70 km/s) will result in hypervelocity dust impacts on DISC. Combined with the range of dust particle sizes, this will create a wide range of impact momentum (10-11–10-3 kg/m/s). To cover the upper part of the momentum range, DISC calibration will be performed with hypervelocity simulated impacts induced by lasers. To perform DISC characterization and calibration in the lower momentum range, we carried out experiments at the Light Gas Gun Impact Facility at the University of Kent (UK).

To calibrate DISC and check the sensing element formed by the aluminum plate and the piezoelectric transducers:

• We performed 9 shots at the Light Gas Gun Impact Facility at the University of Kent. We used different particle sizes and materials and different speeds, utilising different approaches, i.e. single particles with diameters down to 400 nm and buck-shots of a mixture of minerals and very light hollow spheres.
• The signals from the piezoelectrics will be used to verify DISC estimated performance and enable a generally-valid impact sensor calibration procedure.

All 9 shots provided signals, this was for both single impacts and multiple buck- shot impacts. The results of the experiment confirmed the capability of the instrument to measure the momentum of particles impacting in the hypervelocity range.

20-EPN2-098: Constraining the Thermal History of Water-Rich Asteroids Using Noble Gas Analysis of Heated CM Chondrites

Visit by Ashley King and Helena Bates (Natural History Museum, UK) to TA2.15 ETH Zurich Geo- and Cosmochemistry Isotope Facility (Switzerland).
Dates of visit: 28 November – 08 December 2022

Report Summary:

In this TA visit, the team investigated the abundance and isotopic composition of noble gases (He – Xe) in CM chondrites that record both aqueous and thermal metamorphism. These unusual meteorites are likely good analogues for the types of material found on the surfaces of primitive C-type asteroids; however, the timing and mechanism of the metamorphism remains unknown.

The team measured He – Xe in five CM chondrites that experienced peak metamorphic temperatures of <300°C to >750°C using stepped-heating and the “ALBATROS” mass spectrometer at the ETH Zürich Geo- and Cosmochemistry Noble Gas Laboratory. Preliminary results show that the concentrations of ⁴He and ²²Ne are depleted in the lowest temperature steps (300 and 450°C) for all samples, consistent with degassing during (a) metamorphic event(s). Peaks in the concentration of both light and heavy noble gases in the 660°C and 800°C steps agree with previous estimates of metamorphic temperatures based on mineralogy and H₂O loss. Isotopic compositions are mainly a mixture of primordial (so-called Q/HL) and cosmogenic components. In addition, EET 96029 and WIS 91600 contain a trapped solar wind component, suggesting that these meteorites may have been heated by impacts during residence in the asteroid regolith. Comparison of the data to unheated CM chondrites will be used to further constrain the thermal history of C-type asteroids in the early Solar System.

Read the full scientific report with kind permission by Ashley King and Helena Bates.

20-EPN2-071: Deposition of organic matter as a factor controlling microbial colonisation of analogue terrestrial surfaces

Tina Santl-Temkiv (Aarhus University, Denmark) to TA1 – Iceland Field Sites, MATIS
Dates of visit: 29-30 June 2023

This project was designed to improve the understanding of biosignatures in analogue terrestrial surfaces, volcanic rocks, that result as a consequence of microbial colonisation and weathering. During the visit, the automatic medium-volume sampling system PNS DM — modified to run on batteries charged with solar panels — was assembled, tested, and calibrated in the laboratory of Matis.

Due to a delay in shipment of the solar panels, the installation of the system at the field site could not be performed but will be finalised by the host institution in the near future. As a part of the visit, the area of the Fagradalsfjall volcano was visited and the location where the sampling system will be installed was discussed. Once the sampler system will be installed in proximity of the Fagradalsfjall volcano crater, aerosol samples will be collected continuously for a year along with replicate rock samples in order to investigate the impact of aerosol deposition on rock microbial community assembly, using microbial, chemical and physical analysis. This will be performed in collaboration between the team of Prof. Viggó Þór Marteinsson and the team of Assoc. Prof. Tina Santl-Temkiv and will result in greatly improved understanding of colonisation, community assembly, and biosignature emergence in analogue terrestrial surfaces.

Read the full scientific report with kind permission by Tina Santl-Temkiv.

Banner image: Iceland’s Fagradalsfjall volcano. Credit: CC BY-SA 4.0 Mokslo Sriuba

20-EPN2-91: Experimentally determined distribution of highly siderophile elements between sulfide and silicate melts at highly reduced conditions: implications for terrestrial late accretion models

Visit by Edgar Steenstra, Institute of Mineralogy, WWU Muenster (Germany) to TA2.2 VU (Exo)Planetary Interior Simulation Laboratory (PISL).
Dates of visit: 22 – 24 November 2022

Report Summary: Fifteen high-pressure experiments on the PISL end-loaded piston cylinder press were performed at 1 GPa and 1873 K to systematically investigate the effects of Cu and Ni on metal- and sulfide-silicate partitioning of highly siderophile elements (HSE) Pd, Ru, Pt and Ir. Run times at peak conditions varied around 60-90 minutes. The starting compositions consisted of silicate, sulfide and metal powders with added metallic Si. The experimental run products consist of well-segregated metallic and sulfide blobs in a silicate glass. The addition of metallic Si and the initial reduction of the experiments result in the suppression of nugget formation. The glass does contain minute specks typical of S- saturated silicate melts – subsequent LA-ICP-MS measurements of the run products show that these specks do not contain HSE, as initially hypothesized. Electron microprobe and LA-ICP-MS analyses further show that the experimental run products are homogeneous and no compositional zoning was observed. Initial results show that the addition of Cu and Ni to the sulfide liquid decreases the O content of that sulfide liquid at a given FeO value of the silicate melt. This will most certainly affect the partitioning of the elements of interest – preliminary results for Pt confirm this by its variation by three orders of magnitude at a given FeO content. Preliminary results also show that Pd, Ru, Pt, Ir are all preferentially partitioned into the metallic liquid instead of the sulfide melt, confirming their preference for S-poor alloys relative to S-rich liquids. 

20-EPN2-119: Distribution of sulfide-loving elements between major (mafic) mineral phases and silicate melts

Visit by Stephan Klemme and Edgar Steenstra, Institute of Mineralogy, WWU Muenster (Germany) to TA2.2 VU (Exo)Planetary Interior Simulation Laboratory (PISL).
Dates of visit: 22 – 24 November 2022

Report Summary: Twelve high-pressure experiments on a piston cylinder press were performed at 1 GPa and 1673-1873 K to systematically investigate the sulfide-silicate partitioning of chalcophile elements as a function of (non-FeO) silicate melt compositional terms. Run times at peak conditions varied around 70 to 220 minutes. The starting compositions consisted of silicate and sulfide powders. The experimental run products consist of well-segregated sulfide blebs in a silicate glass. The glass contains minute sulfur blebs but subsequent LA-ICP-MS measurements showed that these blebs do not contain the elements of interest and are composed of Fe-S-O.   Electron microprobe and LA-ICP-MS analyses further showed that the experimental run products are homogeneous and no compositional zoning was observed. 

Initial results show that variations in silicate melt composition affect the partitioning of chalcophile elements in a non-ideal way – i.e. FeO activity varies significantly across different melt compositions, thereby affecting the geochemical behavior of the elements of interest. Therefore, it can be expected that in an arc-type differentiation suite the sulfide-silicate partitioning behavior may vary significantly, purely due to variations in FeO activity due to variable silicate melt compositions. 

20-EPN2-009: High-precision oxygen isotope composition of Martian meteorites and their components – insights into the accretion history of Mars

Virtual visit by Siw Egdalen, University of Copenhagen (Denmark) to TA2 Facility 22 – Open University Laser Fluorination Oxygen Isotope Facility (UK).
Dates of visit: 24 May – 11 June 2021

Analyses of Martian meteorites and their components predicts the existence of three main geochemical reservoirs on Mars, namely an enriched crust, a complementary depleted lithospheric mantle, and, lastly, a primitive asthenospheric mantle. Investigating the oxygen isotope composition of these reservoirs is critical for a full understanding of the accretion history of Mars. The Δ17 O composition of ~0.3‰, defined by the SNCs is believed to reflect the primary planetary composition of the martian mantle (1). However, analyses of ancient (>4.5 Ga) individual zircons and minerals from the NWA 7533 regolith breccia, record Δ17 O values that are characterized by a much heavier Δ17 O composition and thus different from the SNCs (2,3). A population of young zircons (<1.5 Ga), also from NWA 7533, are derived from a primitive reservoir located in the deep martian interior, as they are characterized by chondritic-like initial Hf isotope composition (4). 

The oxygen isotope composition of a single grain from this population, indicate that this reservoir may be characterised by a different Δ17 O than the SNCs. If correct, the SNCs might not be representative of the bulk martian composition, but plausibly reflecting interaction with a heavy Δ17 O surface reservoir. Therefore, a main objective behind this study was to obtain high-precision oxygen isotope composition of 10 SNC meteorites to potentially detect Δ17 O heterogeneity. However, initial results show no isotopic variability, thus suggesting that the SNC source reservoir has not experienced interaction with surface reservoir, or that any heterogeneity has been erased.

Read the full scientific report, with kind permission from Siw Egdalen.

20-EPN-008: Characterisation of a new type of extraterrestrial material through the study of Cumulate Porphyritic Olivine cosmic spherules

Virtual visit by Alice Stephant, Istituto di Astrofisica e Planetologia Spaziale (Italy) to TA2 Facility 21 – OU NanoSIMS 50L (UK).
Dates of visit: 24 March – 25 August 2022

One of the major unresolved questions in the field of cosmochemistry is to understand the source(s) and timing of volatile delivery in the inner Solar System. The goal of this project was to examine primitive achondrites which volatile inventory has not yet been investigated, in order to determine what portion of these volatiles was incorporated in the early stages of the Solar System history, relative to late-veneer delivery. In this regard, primitive achondrite acapulcoites and lodranites were selected as they sample a common parent body, hence allowing to also investigate the effect of various degrees of planetary differentiation on volatile abundances and isotopic compositions. 

Using the NanoSIMS 50L at the Open University, we analysed chlorine and water content, as well as their associated isotopic composition in phosphates from three acapulcoites and two lodranites. Our results suggest that the acapulcoite-lodranite parent body incorporated a similar source of volatiles than ordinary chondrites, which chemical composition is similar to the chondritic precursor of acapulcoites and lodranites, arguing for a common reservoir of both Cl and H in the inner Solar System.

Read the full scientific report, with kind permission from Alice Stephant.

20-EPN2-052: Water in silica-bearing iron meteorites – implications for early Solar System dichotomy

Visit by Ana Černok, Freie Universität Berlin (Germany)/University of Trieste (Italy) to TA2 Facility 21 – OU NanoSIMS 50L (UK).
Dates of visit: 14-21 November 2022 and virtual visit from 28 November – 20 December 2022

Understanding the volatile inventory of the earliest Solar System is inseparable from understanding which sources contributed to the volatiles of the oldest and relatively dry non-carbonaceous (NC) objects formed in the inner Solar System, and if they were different from wet carbonaceous (CC) materials, formed in the outer Solar System.

Two questions remain largely unanswered in this respect: (i) What are the abundances and isotopic composition of volatiles in the oldest NC objects and (ii) What were their sources? These questions can be answered by investigating some of the oldest objects in the Solar System, namely, the NC iron meteorites.

This Europlanet visit to the NanoSIMS facility was focused on trying to determine the content and isotopic composition of H or H₂O inside minerals within iron meteorites. The iron meteorites are some of the oldest formed materials in the Solar System and hold key evidence if there has been any water available when they formed, and if there was: where did this water originate from?

Here we focused on understanding water abundance and its isotopic composition in some of the oldest NC silica bearing iron meteorites (IVA type): Muonionalusta, Gibeon and Steinbach. Other investigated irons did not contain any silica. The lowest water content was measured in Gibeon (< 10 ppm) and Muonionlusta (15–20 ppm), while minerals in Steinbach contained significantly more water (40–120 ppm). The δD values for Gibeon show a large range and greater uncertainties, due to low measured water contents. The δD values in Muonionalusta and Steinbach cluster between ~0–300 ‰. In fact, silica phases in both minerals cluster between ~0–200 ‰, while low-water cpx in Steinbach shows the highest δD values (200–300 ‰). The difference in δD values between mineral phases in Steinbach likely reflects the difference in their crystallisation history, where opx may have lost H resulting in increased D/H ratio (higher δD) due to degassing. Overall, the source of water in these NC irons is very similar to that of the Earth and the chondrites, while low-D reservoirs have not been detected.

Read the full scientific report, with kind permission from Ana Černok.