The high-resolution map of Oxia Planum, Mars; the landing site of the ExoMars Rosalind Franklin rover mission

This 1:30,000 scale geological map describes Oxia Planum, Mars, the landing site for the ExoMars Rosalind Franklin rover mission. The map represents our current understanding of bedrock units and their relationships prior to Rosalind Franklin’s exploration of this location. The map details 15 bedrock units organised into 6 groups and 7 textural and surficial units. The bedrock units were identified using visible and near-infrared remote sensing datasets. The objectives of this map are (i) to identify where the most astrobiologically relevant rocks are likely to be found, (ii) to show where hypotheses about their geological context (within Oxia Planum and in the wider geological history of Mars) can be tested, (iii) to inform both the long-term (hundreds of metres to ∼1 km) and the short-term (tens of metres) activity planning for rover exploration, and (iv) to allow the samples analysed by the rover to be interpreted within their regional geological context

Integration of TLS and sonar for the modelling of semi-immersed structures

International audienceIn this chapter, we address the topic of 3D reconstruction of semi-immersed structures from laser and sonar data. We take advantage of recent sonar technologies whose static implementation is close to that of terrestrial laser scanners and which also provide 3D point clouds. After introducing the acquisition devices and their implementation on site, we focus on the characteristics of 3D sonar data and their preprocessing. Then we introduce an original method for combining the heterogeneous data (laser and sonar), captured in different environments. The resulting model was used as a reference to evaluate a mobile mapping system developed later on. Finally, we propose a summary of the contributions and some possible improvements

BUILDING A 3D REFERENCE MODEL FOR CANAL TUNNEL SURVEYING USING SONAR AND LASER SCANNING

International audienc

Identifying biosignatures in a Mars-analogue volcanic rock: The ~3.5 Ga Kitty’s Gap chert

<div> <div><strong>Introduction:</strong></div> </div> <div> <p>Did life ever exist on Mars? This is the question that present and future missions to Mars (MSL, Mars 2020, MSR, and ExoMars) are trying to answer.</p> <p>Although the present conditions on Mars make the presence of extant life highly unlikely at the surface, life may have appeared early in its history, during the Pre-Noachian and Noachian periods, when surface conditions permitted habitability and, potentially, the development of the first forms of cellular life (Cockell et al., 2014; Westall et al., 2015). However, given the conditions of punctuated habitability, if life ever appeared, it most likely remained at a relatively primitive stage of evolution (chemotroph-like organisms, although anoxygenic photosynthetisers cannot be completely ruled out) and the associated remains would be comparable to the very small and subtle chemotrophic microfossils observed in the early terrestrial record (Westall et al., 2015). In order to improve their detection in martian rocks, we therefore study fossil traces of life associated with ancient, 3.45 Ga, terrestrial volcanic sediments whose biological signatures are possible analogues of the signatures of life that could be found on Mars.</p> <p><strong>The 3.446 Kitty’s Gap chert:</strong></p> <p>The 3.45 Ga Kitty’s Gap chert (Pilbara, Australia) is a typical example of silicified volcanic sediments deposited in a shallow, littoral water environment, and in the vicinity of a hydrothermal vent linked to a volcanic system, an excellent analogue for the Noachian environments on Mars (Fig. 1A; Westall et al., 2006, 2011).</p> <p>The Kitty’s Gap sediments hosted microorganisms interpreted as anaerobic, autotrophic chemolithotrophs that colonized the surface of volcanic particles, as well as the dusty matrix (Fig. 1B-C). These kinds of microbes were common on the early Earth, living in anaerobic, volcanic environmental conditions similar to those on early Mars (Westall et al., 2015). The microorganisms occur as silicified, small (< 1 µm) coccoidal structures forming very small and dispersed colonies (Fig. 1D). Moreover, the total sediment is low in organic carbon (0.01–0.05 wt. %). Therefore, the carbonaceous remains of these microorganisms are very subtle and difficult to identify, and their analyses required a multi-technique approach to demonstrate their biogenicity.<strong> </strong></p> <p><img src="data:image/png;base64, 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

Caractérisation multi-technique de microfossiles de 3,45 milliards d'années sur Terre : une approche clé pour détecter d'éventuelles traces de vie dans les échantillons renvoyés de Mars.

International audienceThe NASA Mars 2020 Perseverance rover is actively exploring Jezero crater to conduct analyses on igneous and sedimentary rock targets from outcrops located on the crater floor (Ma´az and Se´ı´tah formations) and from the delta deposits, respectively. The rock samples collected during this mission will be recovered during the Mars Sample Return mission, which plans to bring samples back to Earth in the 2030s to conduct in-depth studies using sophisticated laboratory instrumentation. Some of these samples may contain traces of ancient martian life that may be particularly difficult to detect and characterize because of their morphological simplicity and subtle biogeochemical expressions. Using the volcanic sediments of the 3.45 Ga Kitty's Gap Chert (Pilbara, Australia), containing putative early life forms (chemolithotrophs) and considered as astrobiological analogues for potential early Mars organisms, we document the steps required to demonstrate the syngenicity and biogenicity of such biosignatures using multiple complementary analytical techniques to provide information at different scales of observation. These include sedimentological, petrological, mineralogical, and geochemical analyses to demonstrate macro-to microscale habitability. New approaches, some unavailable at the time of the original description of these features, are used to verify the syngenicity and biogenicity of the purported fossil chemolithotrophs. The combination of elemental (proton-induced X-ray emission spectrometry) and molecular (deep-ultraviolet and Fourier transform infrared) analyses of rock slabs, thin sections, and focused ion beam sections reveals that the carbonaceous matter present in the samples is enriched in trace metals (e.g., V, Cr, Fe, Co) and is associated with aromatic and aliphatic molecules, which strongly support its biological origin. Transmission electron microscopy observations of the carbonaceous matter documented an amorphous nanostructure interpreted to correspond to the degraded remains of microorganisms and their byproducts (extracellular polymeric substances, filaments.). Nevertheless, a small fraction of carbonaceous particles has signatures that are more metamorphosed. They probably represent either reworked detrital biological or abiotic fragments of mantle origin. This study serves as an example of the analytical protocol that would be needed to optimize the detection of fossil traces of life in martian rocks.Le rover Perseverance de la mission Mars 2020 (NASA) explore actuellement le cratère Jezero pour effectuer des analyses sur des roches ignées et sédimentaires provenant d'affleurements localisés sur le fond du cratère (formations Ma´az et Se´ı´tah) et des dépôts du delta, respectivement. Les échantillons de roche collectés au cours de cette mission seront récupérés lors de la mission de retour d'échantillons de Mars, qui prévoit de ramener des échantillons sur Terre dans les années 2030 afin de mener des études approfondies à l'aide d'instruments de laboratoire sophistiqués. Certains de ces échantillons pourraient contenir des traces de vie martienne ancienne qui peuvent être particulièrement difficiles à détecter et à caractériser en raison de leur simplicité morphologique et de leurs expressions biogéochimiques subtiles. En utilisant les sédiments volcaniques du Chert Kitty's Gap de 3,45 milliards d'années (Pilbara, Australie), contenant de potentielles formes de vie primitive (chimolithotrophes) et considérées comme des analogues astrobiologiques pour d'éventuels organismes martiens primitifs, nous documentons les étapes nécessaires pour démontrer la syngénicité et la biogénicité de telles biosignatures en utilisant plusieurs techniques analytiques complémentaires afin de fournir des informations à différentes échelles d'observation. Celles-ci comprennent des analyses sédimentologiques, pétrologiques, minéralogiques et géochimiques pour démontrer l'habitabilité de l'échelle macroscopique à l'échelle microscopique. De nouvelles approches, dont certaines étant non disponibles au moment de la description initiale de ces caractéristiques, sont utilisées pour vérifier la syngénicité et la biogénicité des chimolithotrophes fossiles présumés. La combinaison d'analyses élémentaires (spectrométrie d'émission de rayons X induite par proton) et moléculaires (ultraviolet profond et infrarouge par transformée de Fourier) de morceaux de roche, de lames minces et de coupes au faisceau d'ions focalisé révèle que la matière carbonée présente dans les échantillons est enrichie en métaux traces (par exemple, V, Cr, Fe, Co) et est associée à des molécules aromatiques et aliphatiques, ce qui soutient fortement son origine biologique. Les observations au microscope électronique en transmission de la matière carbonée documentent une nanostructure amorphe interprétée comme correspondant aux restes dégradés de micro-organismes et de leurs sous-produits (substances polymères extracellulaires, filaments). Néanmoins, une petite fraction de particules carbonées présente des signatures plus métamorphosées. Elles représentent probablement des fragments biologiques détritiques retravaillés ou des fragments abiotiques d'origine mantellique. Cette étude sert d'exemple au protocole analytique qui serait nécessaire pour optimiser la détection de traces fossiles de vie dans les roches martiennes