20-EPN2-124: High resolution 14C dating of last glacial loess deposits on Jersey, Channel Islands

Visit by Yunus Baykal, Uppsala University (Sweden), to TA2 Facility 16 – Carbon-14 Dating AMS Laboratory (Hungary).
Dates of visit: 04 – 09 December 2022.

Report Summary: High latitude, ice marginal regions are efficient sources for atmospheric dust. Dust plays a fundamental role in the Earth’s climate system both driving and responding to climate change. Last glacial loess deposits in NW Europe potentially record past dust emissions from regions marginal to the former Eurasian Ice Sheet. However, uncertainties over the age of these deposits essentially limit their potential in reconstructing past dust activity. This project aims to build a detailed chronology of last glacial dust deposition in NW Europe through combined luminescence and ¹⁴C dating of loess on Jersey (Channel Islands).

During the Europlanet-funded 6-day research visit to the ¹⁴C accelerator mass spectrometry laboratory in Debrecen, Hungary radiocarbon dating of fossil gastropods embedded in the loess was conducted. Preliminary results are in good agreement with the existing, yet unpublished luminescence chronology. However, some ages may underestimate the depositional age due contamination from post depositional carbonate leaching. Nevertheless, the ¹⁴C ages from gastropod shells serve as valuable cross check of the OSL data and help to build a more robust age model for the loess section based on two independent dating methods.

20-EPN2-070: Formation of Glycine and Alanine Upon Ion Irradiation of Space-Relevant Ices

Visit by Alejandra Traspas Muina, Queen Mary University of London (UK), to TA2.11 Atomki Ice Chamber for Astrophysics / Astrochemistry (ICA) (Hungary).
Dates of visit: 20 March – 2 April 2023

Report Summary: The experiments initially proposed aimed to investigate the formation and chemical evolution of both glycine and alanine under space relevant conditions. Following a systematic approach, the TA was divided into three projects carried out by a multidisciplinary group of scientist (chemists, biologists, astrophysicists and engineers): looking at (i) experimental insights into the microphysics of molecule destruction and sputtering of CO₂ exposed to cosmic rays analogues; (ii) the formation of methyl formate and its isomers (glycolaldehyde and acetic acid) through the systematic irradiation of H₂ CO:CO, H₂ CO:CH₄ , and H₂ CO:CH₃ OH ice mixtures with 1 MeV and 200 keV H⁺ ; (iii) and 1 MeV H⁺ irradiation of pure Glycine and Glycine:CH₄ interstellar relevant ice mixtures, exploring the survivability and stability of this amino acid in astrophysical relevant environments.

The three projects were designed with incremental molecular complexity to investigate the chemistry of many precursors of simple amino acids. Moreover, the sub-projects were designed to be connected to other awarded TAs either at ICA or AQUILA (PIs: Ivlev, Ioppolo, and Hopkinson) in a synergic manner. For instance, the work of H₂ CO completes the systematic study on methyl formate and its isomers, started at this Europlanet facility 2 years ago, trying to improve the understanding of the standing dichotomy on the formation of glycolaldehyde, methyl formate, and acetic acid. All these species are detected in space in star-forming regions and are considered prebiotic molecules.

Full scientific report published by kind permission of Alejandra Traspas Muina

20-EPN2-017: Resolving critical uncertainties in the impact of geomagnetism on in situ cosmogenic nuclide production via long-term calibration

Visit by Gordon Bromley, University of Galway (Ireland), to  TA2.10 Stable, Rare Gas and Radiogenic Isotope Facility at CRPG (France).
Dates of visit: 17 – 21 October 2022

Report Summary: Cosmogenic nuclide (CN) surface-exposure dating (SED) has revolutionised geomorphology in recent years, enabling the direct determination of both the rate and age of Earth surface-processes. However, SED relies on strict quantification of CN production rates (PRs) for both the time-period and location in question; for many sites and times periods such data is rare. As a result, calculated exposure ages may vary significantly depending upon the assumptions and model schemes employed in calculations. The impact of geomagnetic field variability on nuclide production is particularly uncertain.

The goal of this project is to test explicitly the methods used to calculate exposure ages, and to assess their viability over space and time. To do this, we measured cosmogenic helium-3 within a series of Peruvian lavas of varying age at the Stable Rare Gas and Radiogenic Isotope Facility, CRPG (France). Paired with later Ar/Ar age determination, we are using these new cosmogenic helium data to produce a series of discrete CN production rates from a single geographic region, and so will assess the variability of nuclide production through time. Our preliminary results indicate the research plan is viable: cosmogenic helium data from single lava flows are internally consistent. Lavas analysed range in age from ~1.6 ka to ~175 ka, and so provide a dataset that spans a period sufficient to assess changes in PR and the potential impact of magnetic field variability on CN PRs. We anticipate sharing final project results within a peer-reviewed, open-access publication within the calendar year. 

20-EPN2-053: Noble gas (³He) analyses of iridium poor marine sediments to understand the astronomic process responsible for the late Eocene meteor shower

Visit by Jörg Fritz, ZERIN (Germany), to TA2.10 Stable, Rare Gas and Radiogenic Isotope Facility at CRPG (France).
Dates of visit: 06 – 15 April 2022

Report Summary: The project aims to understand the astronomical processes leading to the late Eocene shower of extraterrestrial (ET) material onto Earth. The ³He-carrier phases responsible for the ~ 2 million years enduring ³He anomaly will be characterised geochemically by producing a combined ³He and Ir dataset.

Here, 23 samples of marine micro-fossil ooze from the ODP 689B core, Maud Rise, Southern Ocean were measured at the CRPG Nancy noble gas laboratory. These samples cover the Eocene Oligocene transition (38 to 33 Ma) and these new data document the amplitude and duration of the  ³He_ET anomaly and confirms that the late Eocene ³He anomaly reported from the Massignano outcrop (Italy) is a global phenomenon. The here-investigated 689B micro-fossil ooze is exceptional because its low terrigenous mineral content and low iridium concentration of 5-15 ppt Ir. These Ir values are close to the expected ET contribution of 12 ppt Ir, as calculated using the current global/annual ET flux and the sedimentation rate and dry density of the 689B deposits.

The ³He data set acquired during the TA visit combined with literature data on Ir concentrations show that the flux of ³He rich ET particles increase by 4 times whereas the Ir concentrations in 689B remain at background values. New Ir data with low detection limits will further constrain the relation between ET ³He and total Ir during the late Eocene shower. ET ³He does not correlate with Ir indicating that the late Eocene ³He anomaly was caused by ³He-rich and Ir poor dust particles. The study illuminates the potential of marine micro-fossil ooze for planetary science.

20-EPN2-072: Dynamics of the early inner solar system inferred from combined 26 Al-26 Mg and Cr–Ti–O isotope systematics of non-carbonaceous chondrules

Visit by Christian Jansen, WWU Münster (Germany) to TA2.9 Ion Probe Facility (IPF), CRPG (France).
Dates of visit: 03-12 August 2022

Report Summary: The advent of non-traditional isotopic systems (e.g., Ti, Cr, Mo) revealed that chondrites—the most primitive witnesses of the early solar system—display a fundamental isotopic dichotomy, with carbonaceous chondrites (CCs) showing large nucleosynthetic anomalies relative to terrestrial standards that are not observed in non-carbonaceous chondrites (NCs). NC and CC reservoirs may thus represent the primordial inner and outer parts of the solar system, respectively. 

The scientific goal of this project is to combine several isotopic systems (O, Ti, Cr) for deciphering the conditions and chronology of chondrule formation in the NC reservoir. A key parameter of this approach is to also have access to the formation ages of these chondrules. This requires in situ measurements with a secondary ion mass spectrometer for determining the ²⁶Al ages of chondrule crystallisation.

To do so, 16 chondrules were separated from the minimally altered ordinary chondrite NWA 5206. They were split into two pieces for determining their (i) Cr and Ti isotopic compositions (bulk measurements) and (ii) O isotopic compositions and ²⁶Al ages. These chondrules show no ⁵⁴Cr or ⁵⁰Ti excesses and classical oxygen isotopic composition (with ∆¹⁷ O ranging from -1 to + 1 ‰). ²⁶Al ages are coherent with previous estimates showing that NC chondrules formed over several million years during the evolution of the inner disk.

20-EPN2-102: A new source of water from Mars

Visit by Tim Tomkinson, University of Bristol (UK) to TA2.9 Ion Probe Facility (IPF), CRPG (France).
Dates of visit: 05-09 December 2022

Report Summary: Here we have searched for a source of D-enriched Martian groundwater previously discovered in the Martian meteorite Lafayette (up to δD 4725‰) within olivine defects below the secondary mineral phyllosilicate. These groundwaters which are known flowed through this sample 670 Ma were sourced from the Martian atmosphere, or had equilibrated with it, and diffused up to ~1.5 µm into the olivine via shock-formed defects in vein walls. In this project we want to determine a calibration line to resolve the water content on the Martian olivines and find a potential location of new water within the defects.

Two 1 inch indium mounts were prepared with olivine plus glass standards and paired Martian nakhlite samples (Yamato 593, 802, 749, Lafayette and Nakhla) to confirm this source of Martian ground water. Work was conducted with Dr Johan Villeneuve and Dr Laurette Piani on the Cameca IMS 1270 E7 ion probe at CRPG, Nancy. The new obtained/formed standards provided calibration to measurements of water contents (H₂O%) within the Martian olivines and when combined with standards from CRPG δD values were roughly constrained. Owing to the unique surfaces of each Martian altered olivine it was impossible to confirm pre analyses if defects hosting water would be present in the outer olivine surfaces. Results show a location where an enriched δD was present, further investigations such as Transmission Electron Microscopy (TEM) are required to confirm this.

20-EPN2-067: Hydrogen isotope compositions of matrices in unequilibrated ordinary chondrites

Visit by Helen Grant, University of Manchester (UK) to TA2.9 Ion Probe Facility (IPF), CRPG (France).
Dates of visit: 10-21 October 2022

Report Summary: One way to study the origin of water and other volatiles which accreted onto rocky planets such as Earth during the formation of the Solar System is to study meteorites that fall from asteroids and other planetary bodies. Hydrogen isotope ratios within meteorites can be used as a tracer for the source of a body’s water, and to an extent spatial and temporal information about the formation of parent bodies. 

Previously, we measured the D/H ratios of bulk powders of a wide range of unequilibrated ordinary chondrites (UOCs), and found wide variations which did not fit into current H-distribution models. Using SIMS, we measured the H, D, C, and Si contents of the fine-grained matrix of 13 of these previously studied UOCs (only falls) ranging from types 3.00 – 3.9. Preliminary results confirm the wide previously observed spread of D/H ratios between samples, including high elevations in a handful of UOCs. C/H ratios will be used to determine the D contribution within samples specific to water, however initial observations confirm contributions from both hydrated and organic components. The results from this visit will be combined with other in-situ studies carried out at the home institution to determine exactly what phases are hosting this highly D-rich material, and how these chondrites affect models of water transport in the early Solar System.

Read the full scientific report, with kind permision from Helen Grant.

20-EPN2-100: Spectroscopic Identification of Experimental Basalt Alteration Products Under Venus Conditions

Visit by Molly McCanta, University of Tennessee (USA), to TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory (Germany).
Dates of visit: 14 – 20 October 2022

Report Summary: Experiments and thermodynamic modelling clearly show that sulfates are a common alteration product under the high temperature, CO₂-SO₂-rich conditions at the surface of Venus. The exact sulfates present depend on the original basalt composition, with anhydrite (CaSO₄) and thernardite (Na₂SO₄) having been observed in the lab (Reid et al., 2023).

Alteration rates calculated from these experiments suggest that sulfate coatings may develop geologically fast and therefore alteration coatings may obscure the original protolith. Additionally, the spectral features of these high temperature sulfates are not well constrained. Although many critical sulfate minerals are stable to temperatures > 500C, previous analytical data has generally explored sulfate-temperature spectral relations to ~100C. The surface of Venus is significantly hotter at 470C. Thus is makes sense to investigate both the effects of variable thickness sulfate coatings and the spectral properties of sulfates under Venus surface conditions to gain a better understanding of their behaviour.

The next set of Venus missions will have observational capabilities in the thermal emission spectrum (range) and high T sulfate spectra are presented in another paper (Dyar ref); here we present data for the effects of high T on visible near-infrared (VNIR) sulfate spectra. In addition, we have conducted experiments to determine the effects of sulfate coating thickness on the underlying surface spectra. The data presented may help determine future mission capabilities to both recognise and analyse sulfate-bearing materials under high T conditions as well as constrain the original, unaltered surface composition.

20-EPN2-050: Turbulent suspensions of volcanic ash: an experimental simulation for eruptive and resuspension ash plumes

Visit by Jacopo Taddeucci and Elisabetta Del Bello, Istituto Nazionale di Geofisica e Vulcanologia, Rome (Italy), to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 07-11 November 2022

Report summary: Ash Injection and settling experiments have been carried out using the environmentally controlled recirculating wind tunnel facility at Aarhus University, in order to understand the processes controlling deposition and segregation of ash from volcanic plumes at stratospheric altitudes.

Ash particles erupted from the Campi Flegrei volcano (Italy) and smaller than 63 micron were injected in the wind tunnel either from the upwind extremity in the presence of wind (1 m/s) or from the side in the absence of wind. The atmospheric pressure in the wind tunnel was systematically varied to simulate the corresponding elevation in the atmosphere from 10 to 50 km. The vertical and horizontal velocity of the particles was measured, as well as the plume opacity, proxy for particle concentration over time.

Settled particles were sampled at different times during the experiments and then analysed for their abundance and size distribution. Both the opacity measurements and the number of particles sampled over time display the decay of particle concentration over time in the suspended plume. The rate of decay is strongly dependent on the atmospheric elevation in a nonlinear way, with modest changes from 10 to 20 km elevation and much larger changes for higher elevations.

From these data we will retrieve experimentally the settling velocity of volcanic ash particles at a range of elevations that is of interest for both aviation and climate modelling implications.

Read the full scientific report, with kind permission from Jacopo Taddeucci.

20-EPN2-051: Evaluation of physical parameters influencing the ice particle transportby wind in a Martian-like environment

Visit by Clémence Herny, University of Bern (Switzerland) to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 16-20 May 2022

Report summary: The transport of ice by wind plays a major role in the surface mass balance of polar caps. Ice can be redistributed by wind due to (1) transport of ice particles and/or (2) transport of water vapour associated with sublimation/condensation. On Mars, although the low atmospheric density is less favourable for the transport of particles than on Earth, both dust and sand have been observed to be transported by wind. Despite ice aeolian landforms have been observed at the surface of the North Polar Cap of Mars, ice particle transport has not been directly observed on the Martian surface. Similarly, no laboratory studies of snow/ice particle transport under Martian-like conditions have been attempted thus far due to the complexity of the material.

In this study we propose to perform experiments in the environmental wind tunnel AWTSII at Aahrus University to study the ice particle transport in a wind-flow under Martian-like pressure and temperature conditions. The threshold shear velocity, which is a critical physical parameter for particle transportation, is determined by analysing the images of the samples acquired during the experimental runs as the wind speed was increased. The influence of ice grain sizes, pressure and temperature are investigated. Results will give constraints on the plausibility of wind driven ice particle transport on Mars.

20-EPN2-023: FLUME-ET: Fluidisation of mass flows by metastable volatiles on extra-terrestrial bodies

Visit by Lonneke Roelofs and Tjalling de Haas, Utrecht University (Netherlands) to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 03-28 October 2022

Report summary: Martian gullies are alcove-channel-fan systems which have been hypothesised to be formed by the action of liquid water and brines, the effects of sublimating CO₂ ice or a combination of these processes. Recent activity and new flow deposits in these systems have shifted the leading hypothesis from water-based flows to CO₂-driven flows. This shift in thinking is supported by the low availability of atmospheric water under present Martian conditions and the observation that gully activity occurs at times when CO₂ ice is present.

We recently performed novel experiments in the Mars chamber at the Open University in the UK that have shown that this hypothesis holds; sediment can be mobilised and fluidised by sublimating CO₂ ice under Martian atmospheric pressure. However, if these experiments work on a larger scale and if these granular-gas flows are able to erode the underlying surface and can explain the formation of Martian gully systems over the long term remained unknown. Therefore, we conducted an additional series of experiments in a larger flume that test the capacity of CO₂-driven granular flows under Martian atmospheric conditions to erode sediment.

These experiments were conducted in a 4 m long flume in the Aarhus Mars Simulation Wind Tunnel. Our experiments show that CO₂-driven granular flows can erode loose sediment under a range of different slopes and CO₂-ice fractions. The results also show that incorporation of warmer sediment increases fluidisation of the mixture, reflected by an increase in gas pore pressure in the flow. These results thus prove that morphological evolution in the gully systems on Mars can be explained by CO₂-driven granular flows.

20-EPN2-066: From Geitafell volcano (Iceland) to Mars: How hydrothermal alteration of basalt can guide our understanding of habitable environments on Mars

Visit by Julia Semprich and Geoff Austin, Open University (UK), to TA1 – Iceland Field Sites, MATIS
Dates of visit: 21 September – 01 October 2022

Hydrothermal systems provide conditions and nutrients for microbial life and thus have the potential to create subsurface habitats on Mars. Characteristic minerals associated with these hydrothermal systems have been detected on Mars’ surface by spectral observations from orbit, but their formation conditions and spatial distribution remain unknown. The aim of this study was a detailed characterisation of the spatial distribution and mineral chemistry of the low-grade metamorphic/hydrothermal alteration mineralogy in an extinct hydrothermal system.

Field work was conducted at the Geitafell central volcano near Hoffell in the south-eastern part of Iceland, an ideal analogue for Mars. The focus of this research was to record spatial relationships between the basaltic host rocks and the hydrothermal alteration in the field and to sample characteristic low-grade metamorphic minerals, which have also been detected on Mars.

We collected 19 samples from different alteration zones within the hydrothermal system including veins and vesicular basalt showing a range of alteration minerals such as carbonates, quartz, zeolites, chlorite, prehnite, epidote, andradite, and actinolite. We will now be able to conduct a detailed study of the samples including petrography, mineral chemistry, and spectroscopy, which can then be used to further constrain our models of hydrothermal alteration on Mars.

We expect this research to be highly relevant to the study of hydrothermal systems on Mars and particularly for sample return once the Perseverance Rover reaches the rim of Jezero Crater, which likely exposed hydrothermally altered rocks.

Banner image: View towards Hoffellsjökull glacier. CC BY-SA 3.0 (Gummao)

20-EPN2-105: Uncrewed Aerial System (UAS) and LiDAR Survey of Relict and Active Periglacial Patterned Ground as Analogues for Mars

Visit by Paul Knightly, Northern Arizona University (USA), and Shannon Hibbard, JPL (USA), to TA1 – Iceland Field Sites, MATIS
Dates of visit: 22-31 August 2022

Uncrewed aerial system (UAS) and LiDAR surveys were performed at periglacial patterned ground sites, including polygons terrain and stone circles, in the Westfjords and Central Highlands, Iceland during the 2022 site field season. Shallow trenches (up to 1 m depth) were excavated to gather in­situ measurements and observations to determine the presence or absence of permafrost and substrate characteristics. No permafrost was observed at either site suggesting the features may be periglacially relict. The processed UAS and LiDAR data will be used to perform morphometric evaluations of patterned ground at each site and compared to previously collected and analyzed morphometric evaluations of periglacially active patterned ground in the Canadian Arctic. The objective of this work is to develop a set of morphometric criteria for distinguishing between active and relict patterned ground. The developed criteria may help inform on the current level (or absence of) periglacial activity and ice content of patterned ground on Mars.

Read the full scientific report, with kind permission from Paul Knightly.

20-EPN2-099: Bioaerosol generation at geothermal systems: Implications for the detection of biosignatures in cryovolcanic plumes at the ocean worlds

Visit by Mark Fox-Powell and Claire Batty, Open University (UK) to TA1 – Iceland Field Sites, MATIS
Dates of visit: 27 July – 09 August 2022

The aim of our project was to capture and study microscopic aerosols ejected from bubbling or geysering geothermal springs in Iceland. Our primary motivation was to understand the potential for biosignatures to become entrained within cryovolcanic plumes at icy moons, such as Saturn’s moon Enceladus, where similar bubbling of hydrothermal gases is thought to drive the formation of aerosols that are then accelerated into space. Fieldwork was conducted at geothermal systems in Iceland in July and August 2022 by a team from the Open University (UK).

We focused our aerosol sampling efforts on two locations that exhibit contrasting aerosolisation regimes: Olkelduhals hot springs, Hverageroi, which exhibit constant, moderate bubbling of geothermal gases, and Strokkur, Geysir, which experiences regular energetic geyser eruptions. Our aerosol flux monitoring showed that geothermal springs are prolific local sources of aerosols, producing fluxes orders of magnitude above background levels. We also found that aerosol production is tightly controlled by bubbling and/or eruption activity.

Successful replicate sample sets were taken at upwind locations to characterise the background aerosol environment, and at multiple downwind locations to capture geothermal aerosols. We also took samples of spring fluids, as the assumed local aerosol sources, and geothermal gases, which are responsible for driving bubbling activity. Ongoing work is investigating the chemical composition, biomass content and microbial diversity of aerosols, and the volatile profiles of geothermal gases. Our data will provide the first insights from natural analogues into the formation of aerosols within cryovolcanic plumes.

Read the full scientific report, with kind permission from Mark Fox-Powell.

20-EPN2-120: A Molecular Toolkit to Hunt and Resolve Fungal Dark Matter (FDM) in Extreme Planetary Environments

Visit by Ali Nawaz and Christian Wurzbacher, Technical University of Munich (Germany) to TA1 – Iceland Field Sites, MATIS
Dates of visit: 19 – 23 July 2022

Fungi are amazing but largely enigmatic creatures with huge diversity and biological potential in any conceivable ecosystem known so far. This holds for our planet, but this also seems true for outer space and other planetary bodies. However, we do not know what kind of extremophile fungi are or have been growing on other planets.

To have a clue, we need to explore extreme analogue sites on our planet using novel and advanced methods. Therefore, we here propose to collect and study samples from various extreme habitats of Iceland using a unique combination of Laser-microdissection of single cells and long-read sequencing to fully resolve the Fungal Dark Matter of Mars-analogue extreme sites in Iceland.

We believe that the outputs of this project will bring novel fungal species into scientific arena and the findings of this proposal will help the broader general scientific community dealing with AstroMycology in specific, and Astrobiology in general, to rightly speculate on the capabilities and limitations of microbial life in extreme environments and correlate it with the conditions of other planets.

Read the full scientific report, with kind permission from Ali Nawaz.

20-EPN2-112: Aeolian saltation at Martian pressures and below

Visit by Philippe Claudin, PMMH – ESPCI – CNRS, Paris (France) to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 30 May – 3 June 2022

Understanding the conditions required for initiating and sustaining sand motion on Mars is important for determining wind strengths required for mobilizing widespread ripples and dunes. Our previous experimental campaign in the planetary laboratory facility of Aarhus has provided evidence for a lower than expected transport threshold and for the emergence of impact ripples at Martian-like pressures. This time, we have made use of a new grain injector set-up at the entrance of the bed, which allowed us to trigger saltation with grains impacting with the granular surface, and therefore to mimic an effective longer bed. Even with a relatively low injection rate, we were able to reach a saturated sediment flux at the bed outlet, characterised by a neutral bed (no erosion nor deposition), whereas a purely erosive regime is always observed at vanishing injection. We could measure this saturated flux varying wind velocity in Martian conditions and found that transport can be sustained at even lower values than previously reported. With the analysis of the erosion profile along the bed, we shall furthermore be able to extract the saturation length. Finally, we recorded movies of grain motion close to the bed with a high-speed camera, which will allow us to study the properties of grain trajectories in the saturated state.

Read the full scientific report, with kind permission from Philippe Claudin.

20-EPN2-092 Characterising fine-grained rims in CO chondrites to understand the mineralogy of the protoplanetary disk

Visit by Enrica Bonato, Deutsche Zentrum für Luft und Raumfahrt (DLR), Institute for Planetary Research (Germany) to TA2 Facility 3 – NHM Petrology, Mineralogy and Chemistry Facility (UK).
Dates of visit: 1-17 February 2022

Report Summary: Carbonaceous chondrites meteorites are amongst the most primitive extra-terrestrial materials available for study and can be used to understand the formation and evolution of the solar system, as they preserve components that formed and evolved in the protoplanetary disk. They are constituted by chondrules, Calcium and aluminum rich inclusions (CAIs), amoeboid olivine aggregates (AOAs) set within a fine-grained matrix. 

Matrix material can be divided in two components: inter-chondrules matrix and fine-grained rims (FGRs) which envelopes chondrules. A major question is the understanding of the relationship between these two components, as a recent study on Te and Cr isotopes concluded that they formed from different precursor materials and therefore in different locations of the protoplanetary disk. Some of the most primitive CO3s like DOM08006, NWA7892, MIL090010 were analysed with SEM-EDX and EMPA. 

A novel approach for characterisation of the modal mineralogy of the FGRs it was used in this project, which involves chemical modelling based hyperspectral imaging techniques for scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS).Moreover, preliminary interpretation of the EMPA chemical data of the FRGs were compared with data collected on the inter-chondrule matrix of the same meteorites. FGRs appears to be consistently richer in FeO throughout the petrologic range in comparison to inter-chondrule matrix, while MgO and Cr₂O₃ content is very similar.

20-EPN2-064: High-precision isotope analysis of individual melt inclusions – Reassessing the compositional variability of Earth’s mantle

Visit by Felix Genske and Misha Böhnke, Westfälische Wilhelms-Universität Münster, Institut für Mineralogie (Germany) to TA2.1 VU Geology and Geochemistry radiogenic and non-traditional stable Isotope Facility (GGIF).
Dates of visit: 14-19 November 2022

Report Summary: In a unique approach, we acquired high precision Nd isotope data on well-characterised sample sets of silicate melt inclusions (MI) from the islands of Gough and Tristan da Cunha in the South Atlantic ocean. These data were collected using a Thermo Scientific Triton Plus TIMS at the VU Amsterdam. Melt inclusions from single or multiple olivine crystals were analysed and the new data provide insights into the magnitude, origin, and mode of sampling of the isotopically diverse materials that represent Earth’s mantle. The most prominent finding of this study is the extended isotopic variability of mantle melts, indicating that the mantle itself is more heterogeneous than assumed from studies of lavas (i.e. whole rocks). Further, the new data from melt inclusions entrapped in lavas from different islands greatly extend the known isotopic variation not only from individual eruption centres but also on a global scale.

Although observed small-scale mantle heterogeneity may exist down to the meter-, perhaps even cm-scale, the former also implies that distinct isolated large-scale (100’s km) reservoirs in Earth’s mantle (and other rocky planets) may not exist. Instead, the efficiency of mantle mixing via convection with time plays a more important role than previously thought; indeed, the existence of the full spectrum of mantle heterogeneity may be captured within single eruptions. As a consequence, the significance of large-scale distinct mantle domains detected by seismic imaging is questioned by our findings.

Read the full scientific report, with kind permission from Felix Genske.

(Image: Gough Island. Credit: L Kurtze)

20-EPN2-020: Towards Prospecting Ore Deposits on Mars – Remote Sensing of the Planetary Field Analogue in the Rio Tinto Mining Area, Spain.

Visit by Jakub Ciazela and Dariusz Marciniak (Institute of Geological Sciences, Polish Academy of Sciences, Poland) to TA1.2 Rio Tinto (Spain).
Dates of visit: 17-27 March 2022

Report Summary: The Rio Tinto area hosts the largest known volcanogenic massive sulfide deposits on Earth. The team has investigated 614 sites along a river bed located 3m from each other. At each site, they investigated 5 random samples for pyrite content. The pyrite content was always estimated by 2 to 4 researchers, and the average for each site was computed. The average pyrite content in the entire investigated area is 7.0 vol.% (12.6 wt.%). We have observed two fields, 30 x 30 m, and 30 x 60 m, with average pyrite contents >50 wt.%, which should be suitable for its detection from the orbit, both with Sentinel-2 (field resolution of 10 m) and Landsat (30 m). Principle Component Analysis of the obtained spectra from Sentinel-2 gives similar results to mineralogical data retrieved in the field during the team’s geological mapping.

By establishing the test field for remote sensing of sulfide deposits in a planetary field analogue on Earth, the team will be able to determine abundance thresholds for the detection of major sulfide phases on Mars and identify their key spectral features. The results will help in 1) more efficient use of the current NIR Martian spectrometers to detect ore minerals and 2) designing new space instruments optimised for ore detection to include in future missions to Mars such as one developed at the Institute of Geological Sciences and the Space Research Centre of the Polish Academy of Sciences called MIRORES (Martian far-IR ORE Spectrometer).

Read full scientific report with kind permission of Jakub Ciazela.

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