22-EPN3-060: A new apparatus for measuring the electrical charge of volcanic ash particles

22-EPN3-060: A new apparatus for measuring the electrical charge of volcanic ash particles

Visit by Allan Fries, University of Geneva (Switzerland), to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 02-11 August 2023

Report summary: The electrical charge carried by volcanic ash particles is known to play a crucial role in the formation of aggregates, which modulate the atmospheric transport and deposition rate of volcanic ash. However, direct field measurements of these charges remain rare, and more investigations are required to better comprehend both charge generation and aggregation mechanisms. This study aimed at building and testing a portable device to quantify the charge of individual volcanic ash particles and aggregates using a Through-Type Faraday Cage (TTFC) connected to a charge amplifier circuit capable of detecting the very small voltages induced by charged particles entering the TTFC.

After building the apparatus, 187 tests were performed, using different quantities and types of particles, as well as varying the measurement technique. First results show that the newly built device is capable of measuring charges down to 0.1 pC and that measurements agree well with alternative estimations obtained by directly integrating the current generated in the TTFC over time.

Beside the charge, results also suggest that the device can be used to obtain the particle settling velocity, based on the duration of the voltage signal. Few additionnal tests are now required to detect smaller particles (i.e., smaller charges) and the instrument will then be used for field analysis and laboratory experiments.

Read the full scientific report, with kind permission from Allan Fries.


22-EPN3-061: CO2 Ice Crystals Formation Under Conditions in the Martian Polar Regions

22-EPN3-061: CO2 Ice Crystals Formation Under Conditions in the Martian Polar Regions: Influence of Substrate Properties and Temperature Gradient

Visit by Ganna Portyankina, DLR (Germany), to TA2.4 Planetary Environment Facilities (PEF), AU (Denmark)
Dates of visit: 30 April – 01 October 2023 (two visits)

Report summary: The main goal of most recent tests conducted at the Planetary Environment Facilities at Aarhus University was to condense CO2 from the chamber’s atmosphere under Martian conditions onto a specially designed set of different surface materials (martian regolith simulant, glass beads of various sizes, dust). We investigated ranges of temperatures and pressures and observed the texture of the created CO2 ice. Our goal was to determine if CO2 deposits over regolith/glass beads/dust differently compared to brushed aluminium. We have observed that various properties of substrate did not considerably alter the deposition morphologies of CO2 observed in our previous work. Most importantly, we find that under conditions usual for Martian polar areas in fall and winter, CO2 ice always deposits as a translucent slab.  Under deviating conditions, i.e. colder temperatures and lower pressures, CO2crystals assume different shapes including opaque slab and highly porous multi-crystalline. Such CO2crystalline morphologies require further investigations, because of their relevance to icy satellite surfaces as well as CO2 cloud formation.

Read the full scientific report, with kind permission from Ganna Portyankina.


Investigating Venus via Volcanic Iceland

Investigating Venus via Volcanic Iceland

Solmaz Adeli and Nils Müller are travelling to Iceland this summer to carry out two research projects in support of upcoming missions to Venus.  Their visit, from 31 July – 14 August, is partly funded through Europlanet’s Transnational Access programme and the trip is part of a larger, international campaign organised by NASA‘s Jet Propulsion Laboratory (JPL) and the German Aerospace Centre, DLR.

Volcanic field sites in Iceland can be used as planetary analogues for Venus, since their resemblance to terrains and environments on Venus enable a better understanding of the processes that shape the venusian surface, and also provide an opportunity to test out instrumentation.

Iceland's Fagradalsfjall volcano
Iceland’s Fagradalsfjall volcano erupting in 2021. Credit: CC BY-SA 4.0 Mokslo Sriuba
3-D perspective view of Sapas Mons on Venus, with lava flows in the foreground. Credit: NASA/JPL

Solmaz, of the DLR Institute of Planetary Research, is leading a project that uses field sites on Iceland to help characterise the composition and origin of the major geologic terrains on the venusian surface, one of the main objectives of the NASA VERITAS and ESA EnVision missions. Her team will use a prototype of the VEM instrument, which will fly on-board VERITAS, to characterise lava flows in the Reykjanes peninsula, which range from very fresh terrains to areas that have been altered over time. “Very fresh” in this case even means that, by coincidence, the team will be able to measure hot lava that is currently erupting from the active Fagradalsfjall volcano since 10 July this year. The red-glowing lava rocks of the Litli-Hrútur eruption cone have about the same temperature as the surface of Venus, which is a 470 degree Celsius hothouse day and night. The team will also collect samples and take them back to the PSL laboratories at DLR-Berlin for analysis in the Venus emissivity chamber

This project will increase our understanding of the spectral emissivity data that will be obtained by the VERITAS and EnVision missions, and be an opportunity to calibrate field data taken by the prototype VEM instrument

Nils, a postoc at the Freie Universität Berlin, is leading a project to better understand volcanic activity on Venus by investigating the infrared signal of active eruptions and searching for new lava flows. The Dyngjusandur sand sheet (a cold sand desert) and the fissure-fed lava flows, Holuhraun and Thorvaldshraun, are excellent analogues on Iceland to prepare for these studies because these recent lava flows at the sites are sufficiently large and intense to be detectable on Venus.

An issue that complicates the quantitative study of volcanic activity on Venus is the unexpectedly low reflected radar signal from Venusian lava flows, which suggests that detection of active  flows may be difficult because they might quickly form uninterrupted crusts, obscuring the hot lava. It is, however, possible that wind-bourne sediments are partly responsible for these low radar reflections. The Iceland volcanic sites are very well-suited to study how sediments modify the radar signal of lava flows, so the study may give new insights into radar data collected at Venus.

The team aims to acquire airborne radar data, similar to the VERITAS radar data, and carry out field work simultaneously with the flight campaign. This ‘ground-truth’ data will include information on sediment coverage and humidity, which will help to interpret and add value to the radar data.

Uli Koehler, from the DLR Institute of Planetary Research, will be travelling with the expedition team and reporting on the campaign. For updates on their progress, see the DLR blog and follow the social media channels of DLR:

Image: CC BY-SA 4.0 Mokslo Sriuba

21-EPN-FT1-012: Zebra dolomites revised

21-EPN-FT1-012: Zebra dolomites revised: clumped isotope analysis as a tool to assess recrystallisation and dolomite cementation in overpressured settings

Visit by Swennen Rudy, KU Leuven (Belgium), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 22-26 May 2023.

Report Summary: Zebra dolomites are marked by an alternation of millimeter thick dark colored, as recrystallised interpreted bands and white cement bands. Disruption of the banding is manifested by displacements that gradually increases and subsequently deceases before disappearing. This disruption also occurs at intracrystalline scale with crystal rehealing features as observable under cathodoluminescence. This disruption of the zebra dolomites is explained by dolomitization in relation to overpressured fluid flow.  

In the framework of the Europlanet project zebra dolomite samples from 3 deep Belgian boreholes (Soumagne, Soiron and Bolland) were selected for clumped isotope analysis.  The aim was to sample and analyse the dark fine crystalline and white coarse dolomite cements separately to infer the original (re)crystallization temperature.  The following research questions were raised: i) is there a systematic difference in deduced temperature between the dark and white dolomite bands.  If so then this could help to better constrain the recrystallisation and cementation.  This would allow to assess the potential resetting of the original clumped isotope signature of the dark bands due to recrystallisation; ii) if the cement phases display uniform temperatures then this temperature can be compared with the minimum crystallization temperature deduced from primary fluid inclusion microthermometry [1]. The discrepancy between both temperatures, which links to the pressure correction, normally allows to quantify the overpressure of the system; iii) based on deduced crystallization temperature and δ18OPDB, the δ18OSMOW of the fluid can be assessed, allowing to constrain the origin of the dolomitizing fluids, certainly when combined with Sr isotope analysis.


22-EPN3-128: Northwestern Amazon regional convection and its role in the control of extreme events and the isotopic signal in Quito, Ecuador.

22-EPN3-128: Northwestern Amazon regional convection and its role in the control of extreme events and the isotopic signal in Quito, Ecuador.

Visit by Maria Sheila Fabiola Serrano Vincenti, Universidad Politécnica Salesiana (Ecuador), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 22-26 May 2023.

Report Summary: The goal of the 2023 visit to the TA Facility was to measure rainwater δ2H and δ18O values sampled at daily and monthly resolution from October 2022 to May 2023 in three different monitoring sites at North, South and Valley sites in Quito-Ecuador. Due to the complex orography, the sites experience varying intensities of rainfall and hailstorms. These measurements are part of a project aiming to understand the dynamical processes that contribute to the observed heavy and extreme precipitation events in the Tropical Andes, specifically in Quito.

Location of the installed rainfall collectors (red) and nearby meteorological REMMAQ stations (cyan). The borders of the city of Quito are marked by the white line.
Location of the installed rainfall collectors (red) and nearby meteorological REMMAQ stations (cyan). The borders of the city of Quito are marked by the white line. Credit: S Serrano-Vincenti.

Understanding these isotopic data will help the interpretation of the variations in δ2H and δ18O during intense rainfall events and subsequent fractionation due to local and upstream convection, orographic lift and moisture recycling. In addition to the measured isotopic signals, rainfall amount, pH, conductivity, and Total Dissolved Solids (TDS) data will be statistically analysed from the sites. Similarly, instrumental daily precipitation and cloud coverage information from instrumental and satellite data will be examined for convective rainfall (thunderstorms) and moisture provenance characterisation.

The Los Gatos spectrometer at the ISIL
The Los Gatos spectrometer at the ISIL Credit: S Serrano-Vincenti.

Read the full scientific report with kind permission by Sheila Serrano-Vincenti.


22-EPN3-086: Exploring the Effects of H+, On+, and Sn+ Irradiation of Water Ice, plus an ISM relevant Molecule, as a Potential Prebiotic Europa Ocean Analogue

22-EPN3-086: Exploring the Effects of H+, On+, and Sn+ Irradiation of Water Ice, plus an ISM relevant Molecule, as a Potential Prebiotic Europa Ocean Analogue

Visit by Alexandra Corrigan, University of Kent (UK) to TA2.12 Atomki-Queen’s University Ice Laboratory for Astrochemistry (Hungary).
Dates of visit: 15 May – 06 June 2023

Report Summary: At the AQUILA chamber in the ECRIS Laboratory at the Atomki Institute for Nuclear Research the effects of H+, O2+, and S5+ irradiation of water ice, plus Formamide, as a potential prebiotic Europa ocean analogue were explored. Three sodium chloride windows, covered with a 1:1 ice mixture of water and Formamide, were irradiated with ion beams. The windows were cooled down to 90K in vacuum, and a 200-250 nm thick ice layer was deposited at them. In the first experiment, the sample was irradiated using a 15keV H+ ion beam in 12 steps, up to a total fluence of 1.1x 1015 ion/cm2. After each irradiation steps an infra-red (IR) spectrum was taken to observe the irradiation products. After completing, the sample was warmed up to 300K in 30K increments, taking an IR spectrum at each interval. During both irradiation and heating, the sputtered molecules were monitored by QMS. Finally, after a full warming up of the cold parts we opened the chamber, removed the sample (for post-TA residue analysis using LCMS/MS), replaced the NaCl window, and pumped the chamber. This protocol was repeated (with different irradiation fluences) for 30keV O2+ and 60keV S5+ ion beams. All the sample windows have been taken for residue analysis. From initial analysis of the spectra it seems that the Formamide was broken, and formed products such as CO, CO2, OCN, and CN. Further investigation is required to confirm these results and to determine what other products were created during the irradiation. 

22-EPN3-088: Scrutinising bio- and geo-signatures in support of the Raman interpretation of space missions data

22-EPN3-088: Scrutinising bio- and geo-signatures in support of the Raman interpretation of space missions data

Visit by Ana de Dios Cubillas, CSIC-INTA (Spain) to TA2.19 Center for Microbial Life Detection, Medical University Graz (Austria).
Dates of visit:17 – 28 April 2023

Report Summary: This project is devoted to investigate geo- and biosignatures that can be preserved in mineral assemblages formed in extreme aqueous terrestrial environments. Environments such as subaerial hot springs that could had existed on early Mars, and cold-seep marine environments that can develop in icy-moon oceans are particularly interesting for astrobiology. In order to achieve this goal, we use information obtained by Raman spectroscopy and SEM/EDX microscopy.

Raman spectroscopy is a recently incorporated analytical technique in the payload of several space missions: SHERLOC@Perseverance, Supercam@Perseverance, RLS@ExoMars and RAX@MMX. It is based on the scattering effect generated by the interaction of photons with the electron density of the chemical bond of a molecule. The position and width of the Raman bands give information on the structure, chemical and isotopic composition and crystallinity of mineral. Studying changes in Raman frequencies allows to evaluate the biological or inorganic origin of the sample. This methodology is relevant for the in-situ identification of geo- and bio-signatures in soil/rock samples collected during space missions.

Several bio-mediated minerals sampled from several hydrothermal and cold-seep areas were characterised by micro-Raman spectroscopy coupled with scanning electron microscopy (SEM/EDX). Obtained Raman spectrum was correlated with its texture in order to identify patterns that would allow us to assess the biological or inorganic origin. We observed Raman band shifting and width changes. These results should be complemented by further experimental work to determine the involvement of bio-mediation processes.

Read the full scientific report, with kind permission by Ana de Dios Cubillas.


22-EPN3-107: Characterising the electron-impact-induced emission of CS2 to constrain sulfur abundances in cometary and planetary atmospheres

22-EPN3-107: Characterising the electron-impact-induced emission of CS2 to constrain sulfur abundances in cometary and planetary atmospheres

Visit by Steven Bromley, Auburn University (USA), to TA2 Facility 13 – Electron Induced Fluorescence Laboratory (Slovakia).
Dates of visit: 08 – 19 May 2023

The main goals of the 2023 visit were to study the electron impact emission cross sections, spectral features, and dissociation thresholds of CS2 gas. The products of CS2 – atomic sulfur and its ions, CS, excited CS2, and CS2+ – make CS2 a rich target of inquiry. Further, the products CS and atomic S are routinely observed in near-nucleus observations of comets (see e.g. discussion in Noonan et al. 2023). Measurements of sulfur abundances in comets show discrepancies between remote and in-situ observations, and improved electron-impact data for CS2 may help resolve this discrepancy. The present experiments are part of a long-term campaign to understand diagnostic electron-impact driven emission and ionization of diatomic/polyatomic molecules in cometary atmospheres. We expect these data will provide valuable insights in one of our ongoing projects to investigate sulfur abundances through analyses of 100+ archived comet observations. In the first week of our visit to the EIF lab, we measured the electron-impact spectrum of CS2 gas at various electron energies between 0 – 100 eV, with energies chosen based on known thresholds for CS, CS2+, and atomic fragment production. During this time, we also began developing an emission model for CS in order to simplify the future analyses of these data. In the second week of the visit, higher-resolution spectra and several cross sections were measured in order to begin comparisons to existing literature. We also identified, for the first time, the emissions of atomic fragments (S I, S II) in the near-infrared red-ward of 600 nm.


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

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

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

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-EPN2-011: Water abundances and hydrogen isotopic ratios of pyroxenes in achondrite meteorites

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

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.


20-EPN2-093: Linear gullies on Mars

20-EPN2-093: Linear gullies on Mars

Visit by Lonneke Roelofs, Utrecht University (Netherlands) to TA2.20 Open University Mars Chamber (UK).
Dates of visit: 21 November – 16 December 2022

Report Summary: A vast range of different gully morphologies occurs on Mars: from the classical gullies, which resemble gullies on Earth, to linear gullies that do not have an Earth counterpart and are found on Martian dunes. Previous experiments have shown that the sublimation of CO2 ice can fluidise and transport sediment in the classical gullies on Mars. However, the linear gullies are hypothesised to form by a different, although related CO2-driven mechanism. For linear dune gullies, it is hypothesised that they form by a block of CO2-ice sliding down the dune. This process has, however, never been observed in real life.

With our visit to the Mars chamber at the Open University, we aimed at deciphering the triggering and forming mechanisms of linear dune gullies on Mars. We identified the possible triggering mechanisms based on hypotheses presented in the literature. The identified mechanisms are; 1) the breaking off and sliding down of CO2-ice blocks, and 2) wind-blown sand being deposited on CO2 frost. We systematically tested these mechanisms in the Mars Chamber at the Open University by means of experiments. For all identified triggering mechanisms a parameter space was used to test the influence of e.g. CO2-ice block size, surface slope and grain size.

With our experiments, we show that CO2-ice blocks slide downslope and create small narrow gullies when dumped on top of fluvial sand, with a large grain-size distribution. However, when dumped on a finer aeolian sand under Martian atmosphere, they do not slide downslope but they dig themselves into the sand, slowly digging a gully downslope by vigorous sublimation and sediment mobilisation. We also show that when a small amount of warm sand is dumped on top of a CO2-frosted the sand is mobilised by CO2 sublimation, but that this process does not create the typical linear gullies we see on Mars.


20-EPN-066: Experimental investigation of CO2 frost condensation and sublimation through sediments in Martian conditions

20-EPN-066: Experimental investigation of CO2 frost condensation and sublimation through sediments in Martian conditions – implications for martian gullies and jets

Visit by Camila Cesar, University of Bern (Switzerland) to TA2.20 Open University Mars Chamber (UK).
Dates of visit: 24 October – 18 November 2022

Report Summary: Our experimental campaign aimed to understand sediment transport driven by CO2 ice sublimation condensed inside a porous regolith. To quantify the erosion of sediment associated
with the sublimation of COfrost in the subsurface of a ~30° slope, we tested various compositions (MGS-1, sand, sand-dust mixtures). While some sediment showed little to no activity over several attempts (sand), others showed significant slope activity (sand + >=10% MGS clay).

Read the full scientific report, with kind permission from Camila Cesar.


20-EPN2-106: The effect of ice substrate to formation of mud flows in a low-pressure environment: insights for Martian sedimentary volcanism

20-EPN2-106: The effect of ice substrate to formation of mud flows in a low-pressure environment: insights for Martian sedimentary volcanism

Visit by Ondrej Kryza, Institute of Geophysics of the Czech Academy of Sciences (Czech Republic) to TA2.20 Open University Mars Chamber (UK).
Dates of visit: 21 June – 12 July 2022

Report Summary: This project was designed to extend previous research of mud behaviour in the low-pressure conditions – with implications for potential sedimentary volcanism on Mars. The main objective was to test the effect of ice (or combined ice-sand) substrate to flow abilities and finite morphology of mudflows. As secondary objectives, testing of various inclinations of the surface, investigation of potential thermal erosion and extended study of another type of surfaces were implemented. 

In the first part of the project, nine successful experiments, with pure and variously inclined (2-10°) ice surface, confirmed a different style of mud propagation than in case of the frozen sandy surface. The major observations are: 1) dominant and prevailing boiling of mud mixture during the propagation over deeply frozen ice surface (confirms significance of latent heat related to melting/recrystallization), 2) explosive potential of ice when in contact with the boiling mud (fracturing, contraction-dilatation). The effect of slope in tested range has no significant impact on these observations.  

The second type of experiments tested combined ice-sand upper lid. Here, transition between boiling and freezing of mudflows was faster and finite morphology was more similar to lava-like flows which were described by Brož et al. (2020a). 

In both cases, the thermal erosion was not confirmed. Moreover, during sectioning and investigation of the finite mudflow shapes and their base, the developed bumps, irregularities or even increased porosity of ice lid were discovered. This might refer to more complex thermal exchange between ice and mud with a sequential melting and re-freezing. 


21-EPN-FT1-016: Metabolic responses of Antarctic melanised microorganism to simulated Martian conditions

21-EPN-FT1-016: Metabolic responses of Antarctic melanised microorganism to simulated Martian conditions

Visit by Ilaria Catanzaro, University of Tuscia (Italy) to TA2.19 Center for Microbial Life Detection, Medical University Graz (Austria).
Dates of visit: 30 May – 03 June 2022

Report Summary: Current hostile conditions on the surface of Mars entail that, if any life form has ever existed on the planet, it may have adopted survival strategies like those evolved by terrestrial microorganisms inhabiting extreme environments e.g. Antarctica. There, one of the most common strategies observed is the cryptoendolithic microbial growth where free-living black fungi living along with algae and lichens within rocky interstices serve as a shield from excessive harmful solar radiation, and their extremotolerance can be mainly due to the presence of thick, highly melanised cell walls.

The ability of these cryptoendolytic microorganisms to thrive under extreme conditions raises the question of whether they cope with them by also regulating their metabolic expression in addition to melanin production, and whether a hypothetical microbial life on Mars could ever have arisen with similar adaptive strategies. In this optic, this study aimed to examin the metabolic regulation of melanised, cryptoendolithic microorganisms in martian scenario. To achieve this goal, colonies of the cryptoendolithic black fungus Cryomyces antarcticus previously exposed to simulated martian conditions such as perchlorates, sulfatic regolith soil and γ radiation, were then analysed with NMR spectrometry at the Center for Microbial Life Detection of the Medical University of Graz. Sample preparation and analysis were carried out in the Facility using standard protocols. Although only preliminary data are available at the time of report writing, significant differences in fungal metabolic expression were observed between the different simulated martian conditions tested.


20-EPN2-078: Metagenomic analysis of the outstanding moonmilk speleothems from Grotta Nera, Majella National Park

20-EPN2-078: Metagenomic analysis of the outstanding moonmilk speleothems from Grotta Nera, Majella National Park

Visit by Martina Cappelletti, University of Bologna (Italy) to TA2.19 Center for Microbial Life Detection, Medical University Graz (Austria).
Dates of visit: 4-7 October 2021, 26 April 2022 (virtual visit)

Report Summary: This project focused on the analysis of three samples from the Black cave (Grotta Nera) located in Majella Park (Abruzzi region, Italy). This cave presents outstanding calcitic moonmilk structures that are unique in the World in terms of both abundance and dimension.

Metagenomic and metabolomic analyses of three samples (A1, apical; A2, lateral; A3, core) collected from one of the moonmilk speleothem from Grotta Nera, were performed. The DNA was extracted using the DNA powersoil kit (Qiagen) modified to include a bead-beating step with MagNA lyser (Roche) for the initial sample treatment. MG-RAST was used to analyse the metagenomic data considering both the taxonomy composition and the functional categories (KO categories). The taxonomy composition of the metagenomic sequences indicated that the dominant phyla were Proteobacteria, Actinobacteria, Firmicutes, Planctomycetes, Acidobacteria, and Verrucomicrobia. Actinobacteria were more abundant in the A1 and A2 as compared to the A3 sample, while in A3 Proteobacteria (in particular, Betaproteobacteria) was enriched as compared to other two samples. The metabolomic analysis was carried out using NMR, extracting the metabolites from 100 mg of each sample (in triplicate). The results indicated that in A2 and A3 samples were enriched by specific metabolites (glycerol in A3 and alanine, acetate, ethanolamine and 3-hydroxybutirate are enriched in A2) suggesting distinct metabolic activities in the microbial communities of these two samples.

Read the full scientific report, with kind permission from Martina Cappelletti.


22-EPN3-032: Soil carbonate clumped isotope-based reconstruction of temperature evolution over the Mid-Pleistocene Transition and thenLate Pleistocene

22-EPN3-032: Soil carbonate clumped isotope-based reconstruction of temperature evolution over the Mid-Pleistocene Transition and the Late Pleistocene

Visit by Ramona Schneider, Uppsala University (Sweden), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 20 February – 03 March 2023.

Report Summary: This study describes the use of carbonate clumped isotope thermometry as a method of reconstructing paleotemperatures from soil carbonate concretions. The method is based on the tendency of rare, heavy isotopes of carbon and oxygen to clump together in a single CO2 molecule, which is temperature-dependent. 

The analysis was performed on 12 samples that forme under a Mediterranean climate regime in Tajikistan to investigate the suitability of these samples for clumped isotope thermometry. The reconstructed temperatures of the Tajik Holocene soil carbonate nodules from three different locations show promising results, indicating that the Δ47 clumped isotope method provides reliable results for this sample type.

The obtained temperature values showed that these carbonates record temperatures that are biased towards summer temperatures. This is likely due to their formation during the summer when temperatures are highest and precipitation ceases after the maximum annual rainfall period. Even the results from older soil carbonates that formed under glacial and interglacial stages dating several glacial cycles back (MIS 11-12 and MIS 21) are well constrained, but a clear difference in formation temperature between glacial and interglacial stages could not be observed. This result can possibly be explained by formation processes of the soil carbonates, but more chronological and temperature data is required to further test this assumption and to investigate which exact period of the geological history is represented by the reconstructed temperatures. Despite these uncertainties, these initial results are very promising and highlight the potential of this method for paleotemperature reconstruction in Central Asia.

Example of a carbonate sample and the tools used for drilling.
Example of a carbonate sample and the tools used for drilling. Credit: R Schneider

21-EPN-FT1-012: Zebra dolomites revised – clumped isotope analysis as a tool to assess recrystallisation and dolomite cementation in overpressured settings

21-EPN-FT1-012: Zebra dolomites revised – clumped isotope analysis as a tool to assess recrystallisation and dolomite cementation in overpressured settings

Visit by Rudy Swennan, KU Leuven (Belgium), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 22 – 31 August 2022.

Report Summary: Zebra dolomites are marked by an alternation of millimeter thick dark colored, as recrystallised interpreted bands and white cement bands. Disruption of the banding is manifested by displacements that gradually increases and subsequently deceases before disappearing. This disruption also occurs at intracrystalline scale with crystal rehealing features as observable under cathodoluminescence. This disruption of the zebra dolomites is explained by dolomitization in relation to overpressured fluid flow.  

In the framework of the Europlanet project zebra dolomite samples from 3 deep Belgian boreholes (Soumagne, Soiron and Bolland) were selected for clumped isotope analysis.  The aim was to sample and analyse the dark fine crystalline and white coarse dolomite cements separately to infer the original (re)crystallization temperature.  The following research questions were raised: i) is there a systematic difference in deduced temperature between the dark and white dolomite bands.  If so then this could help to better constrain the recrystallisation and cementation.  This would allow to assess the potential resetting of the original clumped isotope signature of the dark bands due to recrystallisation; ii) if the cement phases display uniform temperatures then this temperature can be compared with the minimum crystallization temperature deduced from primary fluid inclusion microthermometry [1]. The discrepancy between both temperatures, which links to the pressure correction, normally allows to quantify the overpressure of the system; iii) based on deduced crystallization temperature and δ18OPDB, the δ18OSMOW of the fluid can be assessed, allowing to constrain the origin of the dolomitizing fluids, certainly when combined with Sr isotope analysis.


21-EPN-FT1-010: Tracking the Thermal Evolution of the Miocene Ries Crater Lake as a Potential Analogue for Microbial Habitats on Early Mars

21-EPN-FT1-010: Tracking the Thermal Evolution of the Miocene Ries Crater Lake as a Potential Analogue for Microbial Habitats on Early Mars

Visit by Duncan Mifsud, University of Kent (UK), to TA2 Facility 17 – Isotoptech Stable/Clumped Isotopes Laboratory (Hungary).
Dates of visit: 21 March – 01 April 2022.

Report Summary: We have measured the clumped carbonate (13C18O16O) isotope ratios, as well as the stable isotope ratios δ18O and δ13C, of a number of bioherm, travertine, and crater fill marl samples from a drill core taken from the Nördlinger Ries Crater (NRC) in Bavaria, Germany. The aim of the project was to make use of the clumped carbonate isotope ratios so as to re-construct a palaeotemperature record of the lake environment, which could be used to assess its habitability in the time since its formation. Such information would be useful for assessing the past habitability of similar crater lake environments on Mars, which are presently of great interest.

At first glance, our results demonstrate that the analysed carbonate samples were formed at temperatures well below what would be expected in the NRC lake environment. On closer inspection, however, it was hypothesised that our carbonate samples were either collected from too high up in the stratigraphy, or they were formed under non-equilibrium conditions and thus suffered from kinetic fractionation effects. The result of the latter is a depression of the precipitation temperature as calculated by palaeothermometric scales.

Future studies are planned to investigate samples from suevite (i.e. the oldest crater infill) and to quantify the extent and causes of these kinetic fractionation effects. Future studies on other crater fill marls may thus also be worthwhile.


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