Search

Long-lasting widespread volcanism contributed to heavily shaping the surface of Mars. In fact, the Tharsis volcanic province is one of the largest volcanic provinces with the largest shield volcanoes of the Solar System, Mount Olympus and the NE-SE trending Tharsis Montes, namely Ascareaus, Pavonis and Arsia Mons.However, volcanism on Mars is characterized also by the presence of wide volcanic fields, either in form of small shields or monogenic cones. The region of Syria Planum (SP), located eastern to the Tharsis province and encompassed between Noctis Labyrinthus on the North and Claritas Fossae on the southwest, is an example of diffuse volcanism. SP presents hundreds of small edifices which insist on top of a large bulge roughly 300x200 km in size.New chronological results pointed out a complex magmatic history and volcano-tectonic evolution of the whole Tharsis and SP area spanning from the early-Noachian to the more recent times such as the 130 Ma of the Arsia Mons’ single caldera and the 140 Ma for the Pavonis Mons’ composite calderas. Although through the years SP has been considered the by-product of the enormous volcano-tectonic activity forming the Tharsis, it has been shown that this magmatic complex could be related to large multiple episodes of mantle upwelling forming minor edifices that do not necessarily overlap with the major volcanic centres. Moreover, the NW-SE elongated SP volcanic field grew just south of the Noctis Labyrinthus canyon systems that form a dissected highland and is located at the western tip of the Valles Marineris.In this work, we investigate the geometry of the plumbing system of the SP volcanic field as well as the structures (vent elongation and vent alignment) that fed the magma to forward a possible tectonic and volcanic evolution of the area. The spatial distribution of vents and the overall shape of the volcanic field have been studied in terms of vent clustering and spatial distribution. Moreover, analyzing the lineament pattern on SP and surrounding areas possible links with the formation and evolution of the Noctis Labyrinthus graben, the Valles Marineris and the Tharsis province are forwarded.

The icy satellites of the Solar System, such as Europa and Ganymede, show widespread evidence for tectonic structures that provide insights to infer the kinematics and the mechanical properties of their crusts. Their investigation is pivotal for the understanding of the regimes responsible for their formation and the connection with subsurface layers. Icy satellite tectonics is dominated by extension and shear regimes, while paucity evidence for compression represents an open issue. Structural investigation is constrained at regional-scale coverage of the remote sensing imagery. The research of analogues on Earth represents a strong support for the geologic analysis of the icy satellites. Glaciers represent optimal terrestrial analogues, showing deformation styles similar to those in the icy satellites, and being the excellent sites to further explore, verify and confirm what observed through remote sensing on the icy satellite geology. Although the formation processes differ, the similarity of their structures at surface allows quantifying and predicting the state of deformation in the icy satellites at different scales of investigation. Moreover, glacier deformation shows corridor-like pattern, analogous to the main tectonic setting recognized in the icy satellites. The UPSIDES project aims to investigate and compare the tectonic structures of the glaciers with those on the icy satellites, by means of multi-scale approach of both remote-sensing and field survey. We propose a structural investigation in the Russell and Isunguata Sermia glaciers, located at the western margin of the Greenland Ice Sheet, where field campaign has been conducted under the Europlanet 2024 RI's Transnational Access field analogue in Kangerlussuaq. This project aims i) to achieve knowledge of the tectonic setting at local-scale, ii) to compare with that at regional-scale, and in turn iii) to better understand the tectonic process and to characterize structures that are exclusively identified at regional-scale (such as in the icy satellites). Field measurements of brittle structures (fractures/faults), concerning the quantification of their azimuth, dip, length, width, throw and spacing, have been performed. In parallel, remote sensing analysis, concerning structural mapping on areas covering the locations of the investigated outcrops, allowed to derive the same quantities at regional-scale. In this way, both local- and regional-scale tectonic setting has been investigated, and the stress analysis has been performed. Obtained results have been compared and in turn related with areas that show similar tectonic setting on Ganymede. In particular, the lack of detection of the regional-scale counterpart of the compressional structures that have been recognized at local-scale in the investigated glaciers, has been related to the lack of evidence of such structures in the icy satellite’s surfaces. Such comparison allows us to prepare a tectonic model that suggests deep zones of existence of compressional structures and explains their limited detection at surface and regional-scale investigations.Acknowledgments: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The European Space Agency’s ANALOG-1 experiment is the culmination of 12 distinct METERON experiments carried out since 2011. These all address aspects of teleoperating a robotic asset from an orbital platform, i.e., technical implementation, user interfaces, autonomy and operations. The ANALOG-1 technology demonstration and operations concept experiment is based upon the surface mission scenario segment of the notional EL3 sample return mission. This segment focuses on the control of a lunar surface robotic asset from the Earth and from the Lunar Gateway. The experiment is taking place in two parts, with the first successfully completed from the ISS in November 2019. It assessed the effectiveness of a state-of-the-art robotic control interface to control a complex mobile robot from orbit, as well as evaluating the scientific interactions, during robotic-assisted geology exploration, between crew in orbit and scientists on the ground. Luca Parmitano operated the robot while he was on the ISS. For this experiment, a complex control station had been installed on the ISS. The experiment demonstrated the advantage of having an immersive control station and high level of robotic dexterity, with Luca finishing all his assigned and secondary geology targets ahead of time.

The evolution of the Ladon basin has been marked by intense geological activity and the discharge of huge volumes of water from the Martian highlands to the lowlands in the late Noachian and Hesperian. We explore the potential of the ExoMars Trace Gas Orbiter/Color and Stereo Surface Imaging System color image data set for geological interpretation and show that it is particularly effective for geologic mapping in combination with other data sets such as HiRISE, Context, and Compact Reconnaissance Imaging Spectrometer for Mars. The study area displays dark lobate flows of upper Hesperian to early Amazonian age, which were likely extruded from a regional extensional fault network. Spectral analysis suggests that these flows and the underlying rocks are ultramafic. Two distinct altered levels are observed below the lobate flows. The upper, yellow-orange level shows hundreds of structurally controlled narrow ridges reminiscent of ridges of listwanite, a suite of silicified, fracture-controlled silica-carbonate rocks derived from an ultramafic source and from serpentine. In addition to serpentinite, the detected mineral assemblages may include chlorite, carbonates, and talc. Kaolin minerals are detected in the lower, white level, which could have formed by groundwater alteration of plagioclase in the volcanic pile. Volcanism, tectonics, hydrothermal activity, and kaolinization are interpreted to be coeval, with hydrothermal activity and kaolinization controlled by the interactions between the aquifer and the hot, ultramafic lobate flows. Following our interpretations, East Ladon may host the first listwanite ridges described on Mars, involving a hydrothermal system rooted in a Hesperian aquifer and affecting ultramafic rocks from a magmatic source yet to be identified.

The icy satellites of the Solar System, such as Europa, Ganymede and Enceladus, show widespread evidence for brittle morphotectonic structures (fractures/faults) that provide insights to infer the kinematics and the mechanical properties of their crusts. Their investigation is pivotal for the understanding of the tectonic regimes responsible for their formation. In addition, stress-related structures represent potential conduits or enhanced pathways for fluid migration thus connecting the surface and the sub-crustal layers. Such processes are significant to understand internal processes of icy bodies. Their investigation is constrained at regional-scale coverage of the remote sensing imagery. Glaciers and ice sheets represent optimal terrestrial analogues, showing deformation styles similar to those in the icy satellites, and being the excellent sites to further explore, verify and confirm what observed through remote sensing on the geology of icy satellites. Although the formation processes differ, the similarity of their structures at surface allows quantifying and predicting the state of deformation in the icy satellites at different scales of investigation. The UPSIDES project aims to investigate and compare the tectonic structures of the glaciers with those on the icy satellites, by means of multi-scale approach of both remote-sensing and field survey. We propose a structural investigation in the Russell and Isunguata Sermia glaciers, located at the western margin of the Greenland Ice Sheet. Their investigation attempts: i) to identify scaling laws between the tectonic structures measured in the glacier outcrops and their equivalent mapped on satellite images; ii) to relate and compare such scaling laws with structures mapped on deformed areas of the icy satellites; and iii) to infer the tectonic styles at local-scale on the icy satellites. The knowledge of the tectonic setting at local-scale and its comparison with that at regional-scale, allow us to better understand the tectonic process and to characterize structures that are exclusively identified at regional-scale (such as in the icy satellites). In this contribution we present the preliminary results of the analyses of data collected during the field campaign conducted on July 2021 in Greenland, at the Russell and Isunguata Sermia Gl., in the Europlanet 2024 RI's Transnational Access field analogue in Kangerlussuaq. Field measurements include the characterization of the ice brittle deformation (e.g., fractures and fault) by the quantification of their azimuth, dip, length, width, throw and spacing. This allow us to recognize the tectonic settings and regimes responsible for their formation. In parallel, we performed a structural mapping on satellite images, which cover the locations where the investigated outcrop occur, and we derived the attributes of the mapped structures. We performed then paleo-stress analyses of the data from both local- and regional-scale, which in turn have been related. The obtained results are consistent and suggest strike-slip kinematics. Such results are compared with areas that show similar tectonic setting on Ganymede and Europa and support the understanding of the possible local-scale setting at surface. In addition, the field data allow us to identify the structures that ease the fluid migration. The obtained results from this project aim to contribute to advance the study of icy surface tectonics and will support the preparation of planetary programs, such as JUICE mission, for dedicated observations and target areas. Acknowledgments: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

Introduction: Pit craters are peculiar depressions found in almost every terrestrial body of the Solar System [1]–[4]. Morphologically characterized by circular to elliptical shapes, flat rim and no ejecta blankets. Often found aligned to form a pit chain, or even coalesced with other pits. Depending on their morphology and type of alignemt (e.g. sinuous or straight in presence of faults) their origin may be attributed to either tectonic or to the collapse of a lava tube [2]. On the other hand, atypical pit craters can be found isolated with no major additional surface morphological expressions. In this work, we present a morphometric analysis of one of the atypical pit craters found on the flank of Pavonis Mons. The pit central coordinates are Lon -110.80 Lat 0.33 Data: We used a single stereo pair, ESP_033935_1805 - ESP_041900_1805, acquired by the High Resolution and Imaging Science Experiment (HiRISE) [5]and downloaded from NASA ODE-PDS [6]. Morphometric analysis: We created a high-resolution Digital Elevation Model (DEM) with a spatial resolution of 0.5 m/pixel, using a custom Jupyter Lab environment [7] to process the data with the Integrated Software for Imagers and Spectrometers (ISIS) [8] and the Ames Stereo Pipeline [9]. Finally, using QGIS v3.24, we performed the morphometric analysis, summarized in Table 1. Within QGIS, we digitised the shape of the pit, contouring the rim on the orthoimage, where is clearly recognizible the extension of the pit, as shown in Figure 1. Figure 1. In red, the polygon of the pit, designed over the orthoimage. Then we measured the semi-axis of the ellipse inscribing the shape of the pit and, finally, we used the plugin Volume Calculation Tool to compute the volume of the pit. We also computed elevation contour lines at 2 m interval. Figure 2 shows graphically the results of the analysis. Figure 2. Map of the pit, showing the elevation in blue lines. The pit seems to have two main levels of collapse, an upper level with terraces on both sides, one less developed than the other, and the floor base level. The area of the pit covers approximately 7978 m2, with a perimeter of 336 m. The edges of the enveloping hexagon have an average length of 56m. The bottom of the pit is at approx. 9525 m, while the rim has an average elevation of 9583 m, giving a height of ca. 60m. Analysis of the DEM shows two levels of collapse.The volume computation is underestimated due to the uncertainity of the left terrace. This terrace may be the results of the interpolation performed by the ASP algorithms due to the presence of hard shadows in the stereo pair. Considering that this left terrace cover almost half of the pit, we may infer that the estimated volume may be approximately double the measured volume. Further analysis, including shapes-from-shadows, may improve this result. Parameter Value Volume ~ 303.724 m3 measured, ~ 600 m3 estimated. Area 7978 m2 Perimeter 336 m Average side length ~ 56 m Average Max Elevation (RIM) ~ 9583 m Min Elevation (bottom) ~ 9525 m Maximum Depth ~ 60 m Semi-Major axis ~ 60 Semi-Minor axis ~ 90 Table 1. Summary of the parameters of the Hexagonal Pit, retreived by analysing the high-resolution DEM. As the last step, we imported the DEM as a terrain in Unreal Engine 5, to visualize it in simulated different light conditions, as shown in Figure 3. Figure 3. Pit DEM imported into Unreal Engine 5. The virtual sides of the hexagon are shown in red, while in cyan is highlighted the shadowed area in the stereo pair. Conclusion: The pit presented in this work has some unusual characteristics, its uncommon hexagonal shape, and the absence of connected secondary erosional mechanisms such as impact craters and pits could indicate the presence of structural elements that guided the rupture of the surface. Funding: This study is within the Europlanet 2024 RI, and it has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 871149. References: [1] D. Wyrick, D. A. Ferrill, A. P. Morris, S. L. Colton, and D. W. Sims, ‘Distribution, morphology, and origins of Martian pit crater chains’, J. Geophys. Res. Planets, vol. 109, no. E6, 2004, doi: 10.1029/2004JE002240. [2] F. Sauro, R. Pozzobon, M. Massironi, P. D. Berardinis, T. Santagata, and J. D. Waele, ‘Lava tubes on Earth, Moon and Mars: A review on their size and morphology revealed by comparative planetology’, Earth-Sci. Rev., vol. 209, p. 103288, 2020, doi: https://doi.org/10.1016/j.earscirev.2020.103288. [3] G. E. Cushing, ‘Mars Global Cave Candidate Catalog (MGC3)[abstract 3708]’, 2017. [4] I. S. Hong, Y. Yi, J. Yu, and J. Haruyama, ‘3D modeling of lacus mortis pit crater with presumed interior tube structure’, J. Astron. Space Sci., vol. 32, no. 2, pp. 113–120, 2015, doi: 10.5140/JASS.2015.32.2.113. [5] A. S. McEwen et al., ‘Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE)’, J. Geophys. Res., vol. 112, no. E5, p. E05S02, May 2007, doi: 10.1029/2005JE002605. [6] PDS Geosciences Nodes, ‘Orbital Data Explorer - Mars Holdings’. 2021. Accessed: Nov. 10, 2020. [Online]. Available: https://ode.rsl.wustl.edu/odeholdings/Mars_holdings.html [7] G. Nodjoumi, C. Brandt, and A. P. Rossi, ‘Open-source planetary data processing environments based on jupyterhub and docker containers.’, p. 2, 2022. [8] J. Laura et al., Integrated Software for Imagers and Spectrometers. Zenodo, 2021. doi: 10.5281/zenodo.5347823. [9] R. Beyer, O. Alexandrov, and S. McMichael, NeoGeographyToolkit/StereoPipeline: NASA Ames Stereo Pipeline 2.6.1. Zenodo, 2018. doi: 10.5281/zenodo.1345235.

Introduction: In the Martian North Polar Cap, troughs are formed and enlarged by the erosive action of katabatic winds, blowing perpendicularly with respect to steep edges of the cap. Along these valleys deeper layering of the polar deposits are often exposed making it possible to study the stratigraphy of the upper part of the polar cap [1]. We focused our attention on a 140 km long and 500 m high scarp located in the North-Western edge, facing Olympia Planum, and where part of the North Polar Layered Deposits (NPLD) are exposed. NPLD deposits are finely layered and laterally continuous sequence of light and dark strata with sporadic unconformities in between, whose periodicity has been attributed to climatic and orbital variations [2]. In the polar cap, Tanaka et al. [3] has distinguished different polar units by means of surface image interpretation, hence our scarp exposes Planum Boreum 1 unit overlapped by Planum Boreum 3 unit, both composed of variable ice/dust content, but different thickness. Putzig et al. [4] identified instead seven units inside the polar cap on the basis of the pattern of radar reflections in the radargram-based stratigraphy thanks to the data provided by SHARAD. The stratigraphic sequence of our interest correlates with the upper part of the packet-inter-packet sequence of the unit G by Putzig et al. [4]. The aim of our work is to relate the composition and stratigraphy of the visible layered deposits with the subsurface radar reflectors, using the data acquired by the NASA Mars Reconnaissance Orbiter instruments. Data selection: We performed stratigraphic and geomorphologic interpretation on images of the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE); band ratios and spectral signatures on a hyperspectral cube of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM); subsurface reconstructions on radar reflectors obtained by the Shallow Radar (SHARAD). The integration of the results obtained by such a multi-score data-set underlies the possibility to join the SHARAD stratigraphy with the stratigraphic record recognisable at the surface including its compositional variability (Fig.1). Fig.1 – Data-set: MOLA DEM (a), CTX image (b), CRISM cube (c), HiRISE images (d, e) and SHARAD radargram tracks (f, g, h, i). Black rectangle in the North Polar Cap region shows the study area. Spectral analysis: Spectra for five Regions of Interest (ROIs) of about 50 pixels were acquired and are shown in Fig.2a-b. Fig.2 – (a) Regions of Interest over CRISM image detail; (b) Plot of five ROI average spectra: each colour line represents a ROI spectrum (continuum is removed). The exposed stratigraphy is composed of different amount of dry ice, water ice and basaltic dust [3]. Spectra A and B are well distinguishable, whereas the signatures of C, D and E appear similar, indicating comparable compositions. Spectrum A exhibits well developed water-ice absorption bands (1.5 and 1.95 µm), less development of same peaks might imply an increase of dry ice content. The 1 µm peak (water ice) is well visible in both A and B spectra, but less evident in C, D and E. Multiple absorptions at 1.65 and 2.06 µm, associated to CO2, are well visible in C, D and E. Other absorption bands (at 0.50, 1.02 and 2.30 µm for example) can be related to femic and aqueous alteration minerals. Spectrum A is similar to the signature of pure water ice, with less altered minerals, while C, D and E appear to be characterized by dry ice and femic minerals. Spectrum B appear to be transitional between these two end-members. Spectral indexes: Spectral indexes were produced using CRISM Analysis Toolkit (CAT) [5]. Indexes allowed us to create false colour images to highlight the presence/absence of specific minerals. Example of these are shown in Fig. 3 (see FED for the index definition). Fig.3 – Two false colour images created with spectral indexes (a) BDI1000VIS_BD15002_BD1435 representing ice compositions and (b) OLINDEX3_LCPINEX2_RBR to highlight mineral composition. Mapping and correlation to radar reflectors: Geological units were identified on CRISM and CTX data on the basis of morphology, composition, albedo and their stratigraphic relationship. Fig.4 displays the mapped units. Fig.4 – Geological map and relative units. WI-units: water-ice-rich deposits (blue), WF-unit: water ice and femic minerals deposits (light blue); DF-units: dry ice and femic minerals deposits (green); DI-units: dry-ice-rich deposits (yellow); Aeolian deposits (red); Gravitational deposits (purple). Fig.5 shows the geological units correlated with radargrams features. Variations of dielectric constant among strata are due firstly to presence of water ice in the surficial layers and dry ice in deeper ones, secondly to different amount of dust in radar units. These affect the signal reflectance: stronger if it is from water-ice layers. Additionally, high content of dust significantly decrease the radar signal, so units appear darker [4] [6]. The lines in Fig.5 represent lower contact of the geological units. Fig.5 – Correlation between geological units and radar reflectors. The colours of units are the same of geological map (vertical axis in time). Section track is shown in Fig.1. Discussion and conclusions: We provide a detailed compositional and geometrical characterization (using CRISM, HiRISE, CTX) of outcropping layered deposits of the North Polar Cap, to evaluate the potential for performing sound stratigraphic correlations with the subsurface reflectors identified in SHARAD radargrams. At a scale of single layers, compositional variations of basaltic dust content in the stratigraphic sequence were identified. This variability is visible especially in dry-ice-rich layers. Basaltic dust showed aqueous alteration, especially in water-ice-rich strata. Acknowledgments: We acknowledge support from the EU’s H2020 research and innovation program under grant agreement N° 871149 (GMAP). References: [1] Masse, M. et al. (2012) Earth and Planetary Science Letters, 317, doi: 10.1016/j.epsl.2011.11.035; [2] Byrne, S. (2009) Annual Review of Earth and Planetary Science, 37, doi: 10.1146/annurev.earth.031208.100101; [3] Tanaka, K. et al. (2008) Icarus, 196(2), doi: 10.1016/j.icarus.2008.01.021; [4] Putzig, N. et al. (2009), Icarus, 204(2), doi: 10.1016/j.icarus.2009.07.034; [5] Viviano-Beck, C. et al (2014), Journal of Geophysical Research, 119(6), doi: 10.1002/2014JE004627; [6] Lauro, S. et al. (2012), Icarus, 219(1), doi: 10.1016/j.icarus.2012.03.011.

Lava tubes, or pyroducts [1], are a peculiar type of lava caves originating from basaltic lava flows. These conduits are very efficient thermal structures that allow the lava to cover long distances before cooling down. Lava tubes, are typical features of lava fields found in volcanic-shield islands (e.g. Hawai’i, Canaries, Iceland, etc.) and intracontinental plateaus characterised by gentle slopes ( These structures are easily recognizable from the surface through the presence of skylights and roof collapses aligned in pit-chains, tracing the path of the underground conduit (Fig. 1). Analogous aligned collapses were seen on the surfaces of Mars and the Moon [2]. Thus, the great interest in studying large terrestrial lava tube systems is largely driven by their analogy with their extra-terrestrial equivalents. Figure 1: Comparison of lava tubes from different rocky bodies of the Solar System. From the left: Earth (Undara system, Australia), Mars (Arsia Mons region) and the Moon (Gruithuisen crater). The main difference between structures of different planetary bodies are due to intrinsic physical characters of the parental body and above all gravity. Indeed, a weaker gravity (as in the case of Mars and the Moon) results in higher effusion rates and, thus, larger lava flows and tubes (Fig. 1). This has led to pyroducts which are two or three orders of magnitude smaller in diameter on Earth (10 - 30 m) than on Mars (250 - 400 m) and the Moon (500 - 1100 m) [5]. Despite this different scaling, the largest lava tubes on Earth are considered to be very useful analogues to their extra-terrestrial counterparts. A clear understanding of how large pyroducts form and evolve remains elusive, even on Earth. Within this context, our work aims to identify the processes that shaped the formation of terrestrial lava tubes. Among the most studied pyroducts, the La Corona system (Lanzarote, Canary Islands, Spain) stends out for its geological context within the Canary Island Seamount Province (CISP) on which long-term and spatially focused volcanic activity developed over a poorly mobile tectonic plate. During the last 30 Ma, the absolute motion of the African plate has been nearly stationary (less than 20 mm/yr) [3]. This environment identifies the Canaries as one of the best terrestrial analogues of the Martian one-shell plate volcanism [4], and the impressive dimensions of La Corona lava tube (~9.7 km of total cave development, and a width reaching up to ~28 m for some of its sections) make it one of the most suitable lava tube for interplanetary analogies [6]. In order to understand the origin, evolution and degradation of the La Corona pyroduct, we have carried out a study of the satellite images of the northern region of Lanzarote, followed by field exploration of inner portions of the La Corona lava tube and adjacent areas. Combining terrestrial laser scanner (TLS) technology with field observations and geochemical analyses of the pre-existing lava enabled us to reconstruct the three-dimensional geometry of the lava tube system, the subsurface horizon through which it starts developing, and the volcanic series into which the pyroduct carved its path. What makes this inflated lava tube so interesting is the presence, between the flows the tube has crossed, of a red pyroclastic layer, resulting from the initial Strombolian activity of La Corona vent [7]. This weak layer of pyroclastic material played a major role in the development of the lava tube (Fig. 2), facilitating the emplacement of the inflation process and the excavation that followed [6]. By analogy, similar geological settings could be favourable for the formation of lava tubes on rocky bodies like Mars and the Moon since the volcanic sequences on such bodies can be frequently interleaved by either weak pyroclastic and regolith layers. Other influent parameters controlling erosion include slope variations of the paleo-surface (i.e., knickpoints), and the lava physical properties, both to be well investigated on terrestrial analogues to understand their role even on planetary contexts. Figure 2: Thermo-mechanical erosional stages of the lava tube in cross-sections. a) The primary effusive phase has covered the pyroclastic deposit of the initial Strombolian event; b) the inception of the tube by inflation starts exploiting the pyroclastic layer; c-d-e) progressive erosion and enlargement of the tunnel; f) post-cooling phase. On the walls are visible different layers of linings and flow ledges. The floor is covered by blocks and debris, remnants of the breaking down of the ceiling and lining walls. References [1] Coan, T. (1844). Missionary Herald. [2] Haruyama, J. et al. (2012) Trans. JAPAN Soc. Aeronaut. Sp. Sci. Aerosp. Technol. JAPAN 10. [3] Gaina, C. et al. (2013). Tectonophysics, 604, 4-25. [4] Meyzen, C. M., et al. (2015) Geol. Soc. London, Spec. Publ. 401. [5] Sauro et al. (2020) Earth-Science Rev. [6] Tomasi, I. et al. (pending) JGR – Solid Earth. [6] Carracedo, J. C. et al. (2003) Estud. Geol. 59.

Galileo Regio is a dark terrain of Ganymede extending approximately from 180°-120° W to 0°-60° N that shows high crater density and morphotectonic structures called furrows. Such structures are kilometric-scale brittle troughs bounded by high albedo rims and a low albedo floor, and arranged with circumferential and radial setting at the regional scale [1]. Furrows are generally interpreted as the remnants of a multi-ring impact basin similar to the Valhalla basin on Callisto [2]. Galileo Regio shows two main settings of the furrows, which allow their classification into two systems: the concentric furrows of Lakhmu Fossae system, which is crosscut by the radial furrows of the Zu Fossae system [3]. In addition, Galileo Regio shows local-scale structures that rework the pristine morphology of the Lakhmu Fossae furrows. In this contribution, we investigate the furrows of Galileo Regio at both regional- and local-scale to unravel the tectonic evolution of the dark terrain. We perform a structural mapping and geostatistical analyses of the furrows in Galileo Regio, identifying their hierarchy and tectonic setting originated by regional-scale kinematics. Structure attributes such as structure length, sinuosity, azimuth, spacing within the adjacent structures, have been quantitatively characterized and allow to perform the azimuthal distribution, the Length/Spacing [5] and the paleo-stress analyses [6]. Such analyses allow to identify the structural systems and to infer the past stress fields that affected Galileo Regio (maximum and minimum horizontal stress, i.e., SHmax and Shmin, respectively). A total of four structural systems have been recognized within Galileo Regio: i) the already known Lakhmu and Zu Fossae; and ii) the Lineated system and Precursor system, proposed by this work for the first time (Fig. 1). Such systems are the result of phases of the tectonic activity that affected Galileo Regio during the geologic history of Ganymede. We identify the sequence of such phases that allow to produce an evolutionary tectonic model (Fig. 2): i) t0 represents a NW-SE extension that formed the Lineated system; ii) t1 represents the impact that originated a multi-ring basin [3, 7], i.e., the Lakhmu Fossae; iii) t2 shows the extensional activity responsible for the formation of the light terrain of Uruk Sulcus [8] and for the formation of the extensional structures of the Precursor system; iv) t3 represents the kinematics consistent with the right-lateral transpression that has affected Uruk Sulcus [4] and formed the Zu Fossae; and v) t4 presents a right-lateral strike-slip that contributes to the formation of the Precursor system. The obtained results and the presented model will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument [9] onboard the JUICE mission [10]. Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [1] Patterson, W. et al. (2010). Icarus 207,845–867; [2] McKinnon, W.B. and Melosh, H.J. (1980). Icarus 44 (2), 454–471; [3] Prockter, L.M., et al. (2000). Journal of Geophysical Research: Planets, 105(E9), 22519-22540; [4] Kersten, E., et al. (2021). Planetary and Space Science, 206, 105310; [5] Rossi, C., et al. (2018). Tectonophysics 749, 72–87; [5] Delvaux, D., and Sperner, B. (2003). Geol. Soc., London, Special Publications, 212(1), 75-100; [7] Hirata, N., et al. (2020). Icarus, 352, 113941; [8] Pappalardo, R.T., et al. (1998). Icarus, 135(1), 276-302; [9] Palumbo, P., et al. (2014). 45th LPSC Meeting. Abstract #2094; [10] Grasset, O., et al. (2013). Planetary and Space Science, 78, 1–21.

Landslides are almost ubiquitous in the Solar System, with rockfall and avalanches that are observed also on other terrestrial bodies, such as the Moon (Bart, 2007; Xiao et al., 2013), Mars (Crosta et al., 2018; Lucchitta, 1987) and Mercury (Malin & Dzurisin, 1978). Landslides and mass movements have been observed also on planetary bodies characterized by extremely low gravity, as for example asteroids’ surfaces of Vesta and Ceres (Otto et al., 2013; Schmidt et al., 2017). The behaviour of mass movements on these bodies is poorly studied due to the difficulties of recreating low-gravity experimental conditions or identifying satisfactory analogues for the involved materials. In fact, the overall dimensions and morphology of the resulting deposits (area, width and length) are often the only features that can be studied and compared between different sites or planetary bodies, due to the limitations in DEMs resolution and suitable imagery. In particular, plots of the H/L ratio (drop height/runout length) provide a proxy for the average friction coefficient and have been the subject of many comparative investigations.With the aim of providing a more consistent picture of the possible outcomes of landslides and other mass movements we hereby describe a fully parametric numerical framework based on ESyS-Particle software (Abe et al., 2004; Tancredi et al., 2012), which has been specifically designed to explore the outcomes of fragmenting grain flow under different model assumptions. The framework has been designed to leverage modern distributed computing technologies to increase the number of simulations that can be executed in parallel, and to maximize the usage of already-available computing hardware. Preliminary results and the limitations are also presented and discussed.This framework will support the parametrization of numerical models for the upcoming observations of mass-movements of the future JUICE-JANUS camera observations on Jupiter Icy Moons.Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The surface of Ganymede, which is the biggest satellite of Jupiter, shows strong tectonic deformation affecting both its geologic units, i.e., the younger light terrain and the older dark terrain. The dark terrain is characterized by low albedo, high crater density and furrows, which are morphotectonic structures formed by brittle deformation. Furrows are straight to curved fragments of troughs, with high albedo rims that bound a low albedo floor. Two systems have been recognized at the regional scale, which are the Lakhmu Fossae, whose furrow setting follows a concentric pattern resulting from a multi-ring impact basin, and the Zu Fossae, which follows a radial setting. In addition, local scale structures have been identified superimposed on the regional scale systems, leading to the reworking of the pristine structures. In this contribution, we investigate the tectonic evolution of the furrows in Galileo Regio (approximately from 180°-120° W to 0°-60° N), at both regional and local scale, with the identification of the tectonic events responsible for the deformation of this dark terrain. We performed a structural mapping and geostatistical analyses of the attributes of the mapped structures, such as the length, sinuosity, azimuth, spacing within the adjacent structures. Their quantification allows us to recognize a total of four structural systems within the area and to unravel the paleo-stress fields that have originated them. We prepared an evolutionary tectonic model of the furrow systems of Galileo Regio that shows the dynamics and the induced kinematics. We suggest that Galileo Regio underwent a sequence of tectonic phases associated with extensional and strike-slip regimes, these latter consistent with the kinematics that affected the light terrain of the adjacent Uruk Sulcus. This work advances the assumption that the dark terrain has been later affected by the same tectonics that deformed the light terrain and confirms the rejuvenation of the dark terrain towards a possible future transformation into light ones. The obtained results will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument onboard JUICE mission.Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The surface of Ganymede, the largest satellite of Jupiter, consists of a strongly deformed and tectonized brittle icy crust which stands on top of a large liquid body, possibly a global subsurface ocean. In fact, by means of multiple Galileo orbital mission flybys both geophysical and structural geology measurements constrained the average icy shell thickness to be comprised between 100 and 150 km. The surface can also be divided into two main units: bright and dark terrains depending on their relative albedo, impact crated density and tectonization. Furrows and grooves represent most of the structures on Ganymede’s surface, which are essentially extensional faults, dilatant structures and strike slip faults. We hereby present a 3D geologic modelling of the region of Uruk Sulcus based on structural mapping (Rossi et al., 2020) and using techniques borrowed from oil and gas exploration.The Uruk Sulcus area is a NW-SE bright terrain of ~400 km by ~2500 km size located between 150W-180W and 30N-10S, and characterized by pervasive sets of parallel/sub-parallel grooves of 10s-to-100s km length. The most favored hypotheses relate its formation either to a purely extensional context forming a tilt-block normal faulting, or to crustal necking with creation of horsts and grabens, or to be the result of a major dextral transpression. The overall structural framework and the fault geometries (in the form of 3D meshes) was created according to existing literature and with geologic interpretation and anchored on the surface to the global DEM by Zubarev et al., (2017), and at depth to the brittle ice-subsurface ocean interface to an average value of 120 km. This ice thickness value was obtained, among other methods, also by analyzing the scaling laws ruling the spatial distribution and the length size distribution of grooves and extensional structures, which proved to be fractal. One of the implications of this fractal behavior is that the structures themselves can be interconnected forming a percolating network favoring fluid circulation and connecting the subsurface ocean with the surface (see Lucchetti et al., 2020 and references therein).By means of 3D modelling, we were able to isolate volumes of ice encompassed by major strike-slip structures of Uruk Sulcus and to exploit the scaling laws ruling the structures within such areas, in order to numerically simulate a DFN (digital fracture network) crosscutting the entire volume of ice.This way we could analyze the volume of ice crosscut by such fracture network, and to predict the locations at surface where percolation is favored. Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

Showcase of the 3D explicit reconstruction possibilities on the Crommelin crater inner deposits on Mars

Ganymede’s dark terrain represents the older geologic unit of the satellite, subsequently crosscut by swaths belonging to the younger light terrain. Compared to the light terrain, the dark terrain shows low albedo, higher crater density and morphotectonic structures called furrows. These structures are radial or circumferential fragments of troughs bounded by high albedo rims and a low albedo floor, generally thought being the remnants of a multi-ring impact basin similar to the Valhalla or Asgard basins on Callisto [1, 2]. In particular, in Galileo Regio and Marius Regio, the furrow systems show a concentric pattern centered at around 20° S 180° W, which is the assumed location of the crater formed by an impactor of 50-150 km in radius [3, 4]. Many furrows have been preserved until the present day in their pristine form, while some of them have acted as zones of weakness re-used by subsequent tectonic deformation. For this reason, they show a more complex morphology and are likely considered as precursors of light grooved terrain formation. In this contribution, we perform a structural mapping at the regional scale of the furrows in Galileo Regio, identifying their hierarchy and tectonic setting originated by the regional scale kinematics. Our mapping reveals that transpression, already recognized in the adjacent Uruk Sulcus area [5], affects the dark terrain of Galileo Regio, too. We mapped the structures in Galileo Regio (Fig. 1) by considering their spatial distribution and crosscutting relationships. In addition, we mapped the local-scale fractures that have tectonically modified remnants of furrows by leaving a deformation zone with higher albedo with respect to the surrounding dark material. These fractures show geometries and features associated with the Riedel shear, and synthetic and antithetic structures that form in strike-slip regimes [6]. The NE-SW and NW-SE trending structures that crosscut the concentric furrow systems occur from Uruk Sulcus to approximately 60° N and have been recognized as conjugate (Fig. 2). Hence, the setting of the mapped furrows and their associated structures allows identifying the (paleo)stress field that has affected this dark terrain. We infer that Galileo Regio has been characterized by regional kinematics consistent with the right-lateral transpression that has affected Uruk Sulcus. It is possible to recognize a ≈ NE-SW trending maximum horizontal stress (σh max) responsible for a shortening associated with strike-slip in the area that extends from 180°-120° W to 0°-60° N. Therefore, we can assume that the dark terrain has been deformed by the same tectonic processes that have formed the light grooved terrain of Uruk Sulcus. This work confirms the key role that transpression has played in the leading hemisphere of Ganymede and the reactivation (and possibly the inversion) of the furrows in Galileo Regio, which have followed a deformation history beginning from an impact origin to a tectonic remodeling. Further geo-statistical analysis will be performed to support this reconstruction. Obtained results from this study will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument [7] onboard JUICE mission [8]. Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [1] McKinnon, W.B., Melosh, H.J., 1980. Evolution of planetary lithospheres: evidence from multiringed structures on Ganymede and Callisto. Icarus 44 (2), 454–471. https://doi.org/10.1016/0019-1035(80)90037-8. [2] Prockter, L. M., Figueredo, P. H., Pappalardo, R. T., Head, J. W., & Collins, G. C. (2000). Geology and mapping of dark terrain on Ganymede and implications for grooved terrain formation. Journal of Geophysical Research: Planets, 105(E9), 22519-22540. [3] Prockter, L.M., Collins, G.C., Murchie, S.L., Schenk, P.M., Pappalardo, R.T., 2002. Ganymede furrow systems as strain markers: implications for evolution and resurfacing processes. In: 33rd Lunar and Planetary Science Conference, Abstract #1272. Lunar and Planetary Institute, Houston. [4] Hirata, N., Suetsugu, R., & Ohtsuki, K. (2020). A global system of furrows on Ganymede indicative of their creation in a single impact event. Icarus, 352, 113941. [5] Rossi, C., Cianfarra, P., Salvini, F., Mitri, G., Massé, M., 2018. Evidence of transpressional tectonics on the Uruk Sulcus region, Ganymede. Tectonophysics 749, 72–87. https://doi.org/10.1016/j.tecto.2018.10.026 [6] Fossen, H. (2010). Structural geology. Cambridge, UK: Cambridge University Press. [7] Palumbo, P. et al. 2014. JANUS: The Visible Camera Onboard the ESA JUICE Mission to the Jovian System. 45th LPSC Meeting. Abstract #2094. [8] Grasset, O., Dougherty, M. K., Coustenis, A., Bunce, E. J., Erd, C., Titov, D., et al. (2013). JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system. Planetary and Space Science, 78, 1–21.

The surface of Ganymede has first been observed by the Voyager missions in 1970’s highlighting the presence of a deeply tectonized environment. Galileo Mission in 1996 imaged the Jovian satellites also providing at high-resolution images at targeted places during its flybys. Ganymede's crust is mainly composed of a brittle ice overlying a subsurface ocean, whose depth was constrained to be ~100-150 km [1]. The surface of Ganymede can be subdivided into dark and bright terrains depending on their crater density, differences in albedo and surface morphology. The latter is driven mainly by tectonization, characterized by presence of furrows and grooves. These structures represent the brittle deformation of the icy shell. We focus on the bright terrain located in the region of Uruk sulcus, a NW-SE terrain ~400 km wide and ~2500 km long located between 150W -180W and 30N-10 S strongly deformed by sets of parallel/sub-parallel (often evenly-spaced) grooves both at a regional and local scale. The presence of such structures in light terrains is hypothesized to be determined by tilt-block normal faulting [2], by crustal necking similar to mid ocean ridges [3], or by major dextral transpression, as in the case of Uruk sulcus [4]. It has been demonstrated that such structures show a fractal spatial clustering, and represent a preferential pathway for fluid from the ~100-150 km-deep ocean [1]. We are testing different 3D geomodelling approaches hence deriving more information on both the volume of the fractured brittle ice crust and the most favored location of actual percolation. Nowadays 3D geomodelling is approaching the planetary geology framework, as testified by the outcomes of the PLANMAP Horizon 2020 project [5, 6, 7, 8, 9]. With information either derived from direct surface observations and measurements and/or also constrained by geologic interpretation, it is possible to derive a 3D geomodel of the subsurface that represents specific geologic properties or geometries. We built a preliminary Uruk sulcus model geometry using the global DEM [10] as an initial, low-resolution surface textured with the controlled global mosaic from DLR of Voyager 1, 2 and Galileo images at an average resolution of 359 m/pixel. This served as an upper surface boundary to project the structural mapping from Rossi et al., (2020) and also as an anchor point to reconstruct the major Uruk sulcus structures. As a lower model boundary, the icy crust is constrained at depth by the ocean-ice interface. We used the depth value calculated using the fractal clustering analysis in [1] related to Uruk sulcus. We were able to reconstruct a preliminary qualitative model of the fault geometries for GUS1 (Grooves of Uruk Sulcus 1) system deformation ([4] as a large-scale structural framework. As a first test we focused on a smaller region in the sigmoidal area named S2 and containing the GUS3 (see white square in figure 1b). We extracted a voxel-based volume of icy crust comprised between the surface, the lower ocean-ice interface bounded by the major fault lines delimiting GUS3. At this location a major set of high-angle extensional structures at NE-SW arranged in a right-stepping en-echelon geometry are present, together with other two lower in number grooves families with NW-SE and NS orientations. With this voxel-based volume and knowing the scaling laws of the size distributions of these feature and their azimuths, it is possible to simulate a DFN (Digital Fracture Network) for each of the fractures’ families (fig. 2a). With the DFN it is possible to infer possible high-connectivity locations in the fractured ice volumes and their location at the surface (figure 2b). Further quantitative analysis work on the DFN and the volume of ice will allow to simulate the movement along the major structures backwards and forward in time in order and to capture the strain in the ice volume by incorporating its rheological parameters, and also test the transpression vs necking approach. The 3D geomodelling approach appears as a promising tool not only for scientific analysis but also to identify interesting target of future JUICE observation, where resurfacing or deep fluid expulsions could be more favored. Figure 1: a) The structural map by[4] with the families of grooves (GUS). In b) the 3D geometric reconstruction of the larger GUS1 structures. This analysis is focused in the white box Figure 2: In a) the modelled DFN with the three families of major structures and in b) voxel-based volume showing areas at higher connectivity. Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [3] Pizzi, A., Domenica, A.D., Komatsu, G., Cofano, A., Mitri, G., Bruzzone, L., 2017. Spreading vs. Rifting as modes of extensional tectonics on the globally expanded Ganymede. Icarus 288, 148–159. https://doi.org/10.1016/j.icarus.2017.01.034 [4] Rossi, C., Cianfarra, P., Salvini, F., Mitri, G., Massé, M., 2018. Evidence of transpressional tectonics on the Uruk Sulcus region, Ganymede. Tectonophysics 749, 72–87. https://doi.org/10.1016/j.tecto.2018.10.026 [1] Lucchetti, A., Rossi, C., Mazzarini, F., Pajola, M., Pozzobon, R., Massironi, M., Cremonese, G., 2021. Equatorial grooves distribution on Ganymede: Length and self-similar clustering analysis. Planetary and Space Science 195, 105140. https://doi.org/10.1016/j.pss.2020.105140 [2] Pappalardo, R.T., et al., 1998. Grooved Terrain on Ganymede: First Results from Galileo High-Resolution Imaging. Icarus 135, 276–302. https://doi.org/10.1006/icar.1998.5966 [7] Pozzobon, R., Penasa, L., De Toffoli, B., Rossi, A. P., & Massironi, M. (2020). 3D geo-models based on multiple datasets on Mars (implicit or explicit modelling) (Public D6.1; Planmap Deliverable). [8] Penasa, L., Pozzobon R., Rossi, A. P., Massironi, M., (2020), 3D geo-models based on multiple datasets on the Moon (implicit or explicit modelling) (Public D6.2; Planmap Deliverable). [9] Pozzobon, R., Penasa, L., Massironi, M., Ferrari, S., (2021) 3D geo-models based on multiple datasets on Mercury (explicit modelling) (Public D6.3; Planmap Deliverable). [6] Massironi, M., Rossi, A. P., and the PLANMAP Consortium, PLANMAP Final report 2021 [5] Massironi, M. et al., 2018. Towards integrated geological maps and 3D geo-models of planetary surfaces: the H2020 PLANetary MAPping project, in: EGU General Assembly Conference Abstracts, EGU General Assembly Conference Abstracts. p. 18106. [10] Zubarev, A., Nadezhdina, I., Brusnikin, E., Giese, B., Oberst, J., 2017. A search for Ganymede stereo images and 3D mapping opportunities. Planetary and Space Science 146, 40–54. https://doi.org/10.1016/j.pss.2017.07.021

Rembrandt is a 715 km-diameter basin on Mercury centered at 32.89°S latitude and 87.86°E longitude. This crater constitutes a remarkable example of the stratigraphic variability on Mercury. The uppermost smooth plains of volcanic origin, which are temporally unrelated to the impact event, have been distinguished by the surrounding smooth plains utilizing spectral information. The basin is crosscut by a prominent NE-SW thrust system more than 1000 km long, named Enterprise Rupes (Ferrari et al., 2015; Galluzzi et al., 2015; Semenzato et al., 2020), attributed mainly to crustal shortening induced by global contraction (see Semenzato et al., 2020 and references therein). This consists of a set of lobate scarps and wrinkle ridges with inverse to transpressional kinematics (Massironi et al., 2015). The aim of this work, as part of the PLANMAP Horizon 2020 project, is to use all the available information on the site to provide a comprehensive 3D model of both the structural setting and the thicknesses of the main units of the Rembrandt basin infilling using explicit modeling approach. The principle of three-dimensional explicit modelling relies on the creation of 3D surfaces based on geologic observations and constraints. While implicit modelling and its effectiveness rely on the amount of available data both on the surface and the subsurface to provide a mathematical solution that satisfies all the constraints, the explicit geological modelling implies a more extended geologic interpretation based on the available data which is subject to the operator’s experience and is essentially based on the construction of several interpreted cross-sections to be then interpolated generating mesh surfaces. The advantage is that such type of geologic modelling can be applied in areas with scarcity of data, especially related to subsurface constraints. In the case of the Rembrandt basin, we mainly based our reconstruction on the geo-stratigraphic map and geologic cross-section from Semenzato et al. (2020). Additional constraints, regarding fault kinematics and fault plane geometry, were provided by Galluzzi et al. (2015) and Crane (2020). As a basemap, we used the MESSENGER MDIS global mosaic at 166 m/pixel together with the MDIS global DEM (665 m/pixel), both of them available in the USGS repositories, with the same Lambert Conformal Conic (LCC) projection of the geo-stratigraphic map. In Rembrandt basin two different infillings - the YIP (Young Interior smooth Plains) and OIP (Older Interior smooth Plains) units - overlay the IT (para-autochtonous intracrater plains) base unit. The thickness of these units was estimated with several methods in Semenzato et al., (2020), among which the presence of impact craters excavating and exposing the inner basin stratigraphy. We used such craters for the construction of the interpreted cross-sections in complement to the one by Semenzato et al., (2020). These were subdivided into two intersecting sub-parallel sets. The interpreted subsurface horizons were used for mesh interpolation together with the geologic contacts between the different units on the surface creating meshes representin ghte top of the YIP, OIP and IT basin infilling units. The volume between them was then calculated. The structural modelling was carried out using the structural mapping from Semenzato et al., (2020) and Ferrari et al., (2015). The faults’ vergence and their angles were extracted both thanks to the illumination conditions on the image mosaic and topography, to the measurements provided by Galluzzi et al., (2015) on displaced impact craters and to the work by Crane (2020) and Massironi et al., (2015). This way we were able to model the Enterprise rupes thrust geometry, its splays and backthrusts as well as contractional lobate scarps and extensional radial features within the basin infilling units. Although requiring a certain degree of assumptions especially on planetary bodies, the 3D geomodelling proves to be a useful tool in order to check surface interpretations that might change once set into 3D environment and refine volume calculations and 3D shape of geologic units. Follow up investigations will focus on forward and backwards modeling work on the activity of the Enterprise Rupes system. Figure 1: in a) the mesh construction for the main Enterprise rupes structure, constrained with surface mapped lineaments and anchored on the geologic cross-section. In b) the tetrahedral volumetric mesh representing the two events of Rembrandt basin infilling. In c) the structural and stratigraphic geomodel of Rembrandt basin (https://skfb.ly/6ZqtI). Acknowlegements: This research was supported by the European Union’s Horizon 2020 under grant agreement No 776276‐PLANMAP. References: Crane, K., 2020. Structural interpretation of thrust fault-related landforms on Mercury using Earth analogue fault models. Geomorphology 369, 107366. https://doi.org/10.1016/j.geomorph.2020.107366 Ferrari, S., Massironi, M., Marchi, S., Byrne, P. K., Klimczak, C., Martellato, E., & Cremonese, G. (2015). Age relationships of the Rembrandt basin and Enterprise Rupes, Mercury. Geological Society, London, Special Publications, 401(1), 159–172. https://doi.org/10.1144/SP401.20 Galluzzi, V., Di Achille, G., Ferranti, L., Popa, C., & Palumbo, P. (2015). Faulted craters as indicators for thrust motions on Mercury. Geological Society, London, Special Publications, 401(1), 313–325. https://doi.org/10.1144/SP401.17 Massironi, M., Di Achille, G., Rothery, D. A., Galluzzi, V., Giacomini, L., Ferrari, S., Zusi, M., Cremonese, G., & Palumbo, P. (2015). Lateral ramps and strike-slip kinematics on Mercury. Geological Society, London, Special Publications, 401(1), 269–290. https://doi.org/10.1144/SP401.16 Semenzato, A., Massironi, M., Ferrari, S., Galluzzi, V., Rothery, D. A., Pegg, D. L., Pozzobon, R., & Marchi, S. (2020). An Integrated Geologic Map of the Rembrandt Basin, on Mercury, as a Starting Point for Stratigraphic Analysis. Remote Sensing, 12(19), 3213. https://doi.org/10.3390/rs12193213

Chaotic terrains are broad regions on Mars characterized by the disruption of the basaltic bedrock into polygonal blocks separated by deep fractures. To date, the proposed genetic scenarios often involve the occurrence of subsurface ice or liquid H2O. Nevertheless, similar features also occur within some craters on the Moon, namely floor-fractured craters (FFCs), where water ice reservoirs are not present. We propose a new formation mechanism for Martian chaotic terrains as well as for lunar and Martian FFCs. The proposed mechanism does not require a major role of water but multiple cycles of inflation and deflation of a buried magma chamber. This process results in a particular type of caldera collapse, called the piecemeal (or chaotic) caldera collapse. A series of analog experiments show both geometrical and quantitative correspondence with natural case studies: Arsinoes Chaos (Mars), an unnamed FFC (Mars), and Komarov crater (FFC on the Moon).

Arabia Terra is a region of Mars where signs of past-water occurrence are recorded in several landforms. Broad and local scale geomorphological, compositional and hydrological analyses point towards pervasive fluid circulation through time. In this work we focus on mound fields located in the interior of three casters larger than 40 km (Firsoff, Kotido and unnamed crater 20 km to the east) and showing strong morphological and textural resemblance to terrestrial mud volcanoes and spring-related features. We infer that these landforms likely testify the presence of a pressurized fluid reservoir at depth and past fluid upwelling. We have performed morphometric analyses to characterize the mound morphologies and consequently retrieve an accurate automated mapping of the mounds within the craters for spatial distribution and fractal clustering analysis. The outcome of the fractal clustering yields information about the possible extent of the percolating fracture network at depth below the craters. We have been able to constrain the depth of the pressurized fluid reservoir between ∼2.5 and 3.2 km of depth and hence, we propose that mounds and mounds alignments are most likely associated to the presence of fissure ridges and fluid outflow. Their process of formation is genetically linked to the formation of large intra-crater bulges previously interpreted as large scale spring deposits. The overburden removal caused by the impact crater formation is the inferred triggering mechanism for fluid pressurization and upwelling, that through time led to the formation of the intra-crater bulges and, after compaction and sealing, to the widespread mound fields in their surroundings.

This paper presents the abundances and the size-frequency distributions (SFD) of the ejected boulders surrounding the Linne crater, located on the Moon's Mare Serenitatis basin. By means of Lunar Reconnaissance Orbiter Camera high-resolution images we prepare a context geological map of the Linne crater as well as we identify ∼ 12000 boulders ≥4.4 m, with a maximum measured size of 30.8 m. The cumulative number of boulders per km2 is fitted with a power-law curve with index −4.03 + 0.09/-0.10. By studying the radial ejecta abundances, we find that the largest ones are located within the first 2 km from the crater's centre, while few tens of boulders with sizes 8 m are detectable above 5 km from the crater's rim. We find that the Linne proximal ejecta blanket is slightly asymmetrical, as indicated in the geological map too, showing a density increase in the NE-SW direction. This may be the result of an oblique impact emplacement of the original impactor, or it may be explained with a perpendicular impact in the Mare Serenitatis location, but on a surface with lunar basalts with different local mechanical properties. By exploiting our boulders size density as a function of the distance from the crater's centre, we derive a possible regolith thickness at the Linne impact of ∼4.75 m, supporting similar values based on Earth-based radar and optical data in the Mare Serenitatis basin.

Mounds are positive relief features that can be ascribed to a variety of phenomena; they can be related to monogenic edifices due to spring or mud volcanism, rootless cones on top of lava flows, pingos and so on. In the case of sedimentary or spring case of mud extrusion, these mounds can be widespread regionally and/or contained in large complex craters, often in populations of several hundreds or thousands . Previous work on detection of such mounds in the Mars Arabia Terra involved exploiting morphometric parameters and mapping them onto Digital Terrain Models . In this work, we take a step further and develop more general methods to automatically detect them without explicitly defining the topographical features. We achieve this by using a generative framework trained in an adversarial fashion to produce realistic mappings with only a small number of training samples. Further, we introduce a terrain simulator based on this framework that learns the terrain simulation parameters, and allows us to induce domain specific knowledge automatically into the network. Our key results indicate that learning latent representations based on simulations can offer improvements in detection accuracy, while making it more robust to changing terrain scenarios.

Monitoring of vibrational eigenmodes of an elastic body excited by gravitational waves was one of the first concepts proposed for the detection of gravitational waves. At laboratory scale, these experiments became known as resonant-bar detectors first developed by Joseph Weber in the 1960s. Due to the dimensions of these bars, the targeted signal frequencies were in the kHz range. Weber also pointed out that monitoring of vibrations of Earth or Moon could reveal gravitational waves in the mHz band. His Lunar Surface Gravimeter experiment deployed on the Moon by the Apollo 17 crew had a technical failure rendering the data useless. In this article, we revisit the idea and propose a Lunar Gravitational-Wave Antenna (LGWA). We find that LGWA could become an important partner observatory for joint observations with the space-borne, laser-interferometric detector LISA, and at the same time contribute an independent science case due to LGWA's unique features. Technical challenges need to be overcome for the deployment of the experiment, and development of inertial vibration sensor technology lays out a future path for this exciting detector concept., 29 pages, 17 figures

International audience; Virtual Reality (VR) and Augmented Reality (AR) coupled with 3D terrain reconstructions are increasingly used for science, education and out-reach applications. These techniques are becom-ing more widespread thanks to the release since 2016 of reliable, versatile and cost-effective hardware solutions accessible to the general public. In the field of planetol-ogy, VR and AR theoretically allow the possibility to simulate field trips to remote places that are otherwise inaccessible to humans. Using high-resolution imaging, coupled with spectral or morphological data gathered by robotic explorers (orbiters, landers, rovers), we can cre-ate integrated virtual environments that accurately rep-resent the surface of planetary bodies and allow visual-ization and characterization of different datasets. These virtual environments provide the possibility to navigate on a global scale using orbital data, and move down to the surface when in situ data are available to explore and analyze local outcrops. This is particularly useful in the cases of the Moon and Mars, where both extensive or-bital and in situ data are available.

The volcanic provinces are embedded between the NE margin of b56 /Lennon-Picasso basin and high terrain bounding structures. Resulting plains are interested by endogenic pits associated with pyroclastic activity, in agreement with the observation that Mercury's explosive volcanic vents tend to be located along major fold and thrust belts (Byrne et al 2014) and around large impact basins. Recent large scale mapping defined them intercrater plains partly covered by smooth plains (Malliband et al 2019; Whitten et al 2020). In addition to endogenic pits, these provinces display several 10-km diameter prominent cones, sometimes aligned forming high-relief ridges, resembling constructional edifices. In colour composite images, cone tops are peculiarly darker (blue) or, alternatively, brighter (and yellow) with respect to the surrounding material. On the surface Mercury, Wright et al. (2019) interpreted two randomly located constructional edifices of similar size, attributing their origin to a late highly viscous stage of volcanism that followed lower-viscous stage that are thought to provide typical smooth plains. Wider et al. (2016) proposed that the encounter of highly-viscous lavas with C-rich material during the magma ascent can easily provide volatiles (Zolotov et al. 2011) that progressively accumulate and lead to explosive eruptions. The resulting high reflectance of pyroclastic deposits would arise from removal of graphite as it was consumed during oxidation. The study aims to reveal the nature of cones at the margin of the Lennon-Picasso basin and to explain the relationship between a potential long-lasting volcanic activity and the concurrent global contractional regime.Authors received funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47 and from European Union’s Horizon 2020 research grant under agreement 776276- PLANMAP.

Volcanic activity is widespread within the inner Solar system and it can be commonly observed on rocky planets.In this work, we analyse the structures of Pavonis Mons, which is one of the three large volcanoes in the Tharsis volcanic province of Mars, by performing structural mapping, azimuth, and topographic distribution of linear features on the flanks of Pavonis, such as grabens and pit chains. We tested whether their formation is to be ascribed to the internal volcano dynamics and magmatic activity or the tectonics related to the Tharsis volcanic province activity.Through the length size distribution and fractal clustering analyses of the structural features, we found that large grabens are vertically confined in the upper mechanical layers of the brittle crust whereas pit chains penetrate the whole crust up to the magmatic source, indicating that they can be considered the main feeders of Pavonis Mons. We inverted the topography with dykes and faults models to test whether grabens at the surface are the expression of intrusions at depth and we suggest that thin dykes inducing normal faulting is the most likely mechanism. Furthermore, two azimuthal distribution of the grabens are identified: concentric grabens occur on the volcano summit while linear grabens at its base show NE-SW trend as the Tharsis Montes volcanoes alignment. The analyses show that faults related to large grabens are confined in a mechanical layering in the upper layers of the brittle crust, whereas deeper structures such as pit chains are most likely associated to magma injection/dykes and therefore, connected to the subcrustal magma source at a depth of ~80–100 km.Therefore, based on our results, we infer that Pavonis Mons recorded active rifting at the initial stages of development with the formation of the large linear graben and faults at its base followed by a phase of volcano growth and concentric magma intrusions when volcano and magma chamber dynamics prevailed

Geological units on Earth are defined by several parameters besides the stratigraphic ones, such as rock textures, lithology, composition, and environmental conditions of their origin (numerous and diverse magmatic, volcanic, metamorphic and sedimentary environments). On the other hand, from the Apollo era onward, planetary ‘geologic’ mapping has been carried out using a photo-interpretative approach mainly on panchromatic and monochromatic images. This limited the definition of geological units to morpho-stratigraphic considerations so that units were mainly defined by their stratigraphic position, surface textures and morphology, and attribution to general emplacement processes (a few related to magmatism, some broad sedimentary environments, some diverse impact domains, and all with uncertainties of interpretation). Hence, the two products are still separated by an important conceptual and effective gap which makes the traditional planetary morpho-stratigraphic maps unable to satisfy fully the needs of modern planetary exploration, i.e. an optimised product to define mission strategy in terms of target selection, exploration traverse definition and resource evaluation for ISRU purposes. One of the approaches that might close this gap is to integrate spectral, color and compositional information into morpho-stratigraphic maps, thus generating spectro-morphic or geo-stratigraphic maps.The PLANMAP team has explored diverse methods for the integration of color variation and spectral information into planetary geological maps that diverge on the bases of the data available, the planetary surface under consideration (Moon, Mars and Mercury),the geological environments and the scale of mapping. PLANMAP received funding from the European Union Horizon 2020 research and innovation program under grant agreement N. 776276.

Among the variety of earth analogues, what surely stand out are lava tubes. A lava tube is a type of lava cave formed by a low-viscosity lava flow that can develop 1) forming a continuous and hard crust, which forms a roof above the still flowing lava stream (over-crusting), or 2) slipping between pre-existing lava flows (inflation). The resulting structure constitutes among the most efficient thermal structures on Earth, because of their capacity of thermal insulation isolated lava flows can travel over long distances across lava fields. Lava tubes, which on Earth are typical features of lava fields encountered in intracontinental plateaus and volcanic-shield islands (slopes Indeed, in the last decade, high-resolution orbital images on planetary bodies like Mars and the Moon offer the possibility of studying the morphology of these structures, detecting them from the recurrent collapses in the pyroduct’s roof, that shows the presence and the path of the pyroduct itself. The pit chains show characteristics similar to those on Earth: elongated with minor axis representing the width of the tube and with major axis along the flow direction. The differences in gravity between Earth and the other planetary bodies and its concurrent influence on the effusion rates result in a significant difference in lava tube dimensions, indeed, terrestrial pyroducts tend to generally have a smaller width (10–30 m) than those on Mars (250–400 m) and the Moon (500–1100 m) [3]. In the post-cooling phases, lava tubes are characterized by a near-constant inner temperature and, on other planetary bodies, they might offer natural protection against micrometeorites and solar and cosmic radiations making them ideal locations for future planetary explorations. Within this framework, studying the largest lava tubes on Earth is of interest as they could represent the best planetary analogues. In order to employ lava tubes as locations for future explorations, it is important to understand exactly how they form and develop not only during the active phase (flow-phase) but also and more importantly during the post-cooling phase. Alongside the NW African continental margin (Morocco), is located the Canary Island Seamount Province (CISP), a magmatic province generated by the extremely slow transit (~8–10 mm/yr) of the African plate over a hotspot during more than the last 133 Ma [5] and hence represents both long-term and spatially focused volcanic activity over a poorly mobile tectonic plate. For this reason, it constitutes one of the best terrestrial analogues of the Martian one-shell plate volcanism [6]. In the NE region of Lanzarote (Canary Islands) stands La Corona lava tube system that, with its 7.6 km length and an average width of 30 m [4], is one of the largest volcanic cave complexes on Earth. Therefore, the occurrence of volcanism on an almost stationary plate and the impressive dimensions of La Corona lava tube make it one of the most suitable lava tubes for interplanetary analogies. Different field surveys were conducted over the last two years in order to explore its three-dimensional geometry using 3D laser-scan. These data allowed to place constraints on the tube origin (inflation process rather than over-crusting), the involvement of thermal erosional processes (inferred from characteristic morphologies) and to identify a weak pyroclastic level within the tube which might have favoured the inflated tube inception. Also, the presence of an important amount of secondary mineralisation inside the tube has been very significant in understanding the evolution of the pyroduct in the cooling and post-cooling phases. These secondary mineralisation (mainly sulphates) show an interesting contribution from the Aeolian and marine environment in the latest evolutionary stages of this lava tube. Studying this exceptional example of terrestrial lava tube will allow to improve our understanding of the formation and evolutional processes giving rise to analogue features on other planetary bodies of the Solar System. [1] Haruyama, J. et al. (2012) Trans. JAPAN Soc. Aeronaut. Sp. Sci. Aerosp. Technol. JAPAN 10 [2] Tettamanti C. (2019) Analysis of skylights and lava tubes on Mars, Department of Physics and Astronomy “Galileo Galilei", Univerisy of Padova (Italy) [3] Sauro, F., et al. (2018) 49th Lunar Planet. Sci. Conf. 2018 [4] Carracedo, J. C. et al. (2003) Estud. Geol. 59 [5] van den Bogaard, P. (2013). Sci. Rep. 3 [6] Meyzen, C. M., et al. (2015) Geol. Soc. London, Spec. Publ. 401

A bifocal panoramic stereoscopic camera (BIPS) has been designed a realized as a terrestrial prototype. The core of the camera is a novel Bifocal Panoramic Lens (BPL) we designed and realized, which is able to carry out a panoramic field of 360° in azimuth, 100° in elevation (+60°/-40° with respect to the horizon) and, simultaneously, an enlargement of a part of the panoramic field. All of that using an unique image sensor and avoiding any moving part. BIPS consists of a twin couple of BPLs settled in an appropriate stereoscopic baseline. It allows the monitoring of the surrounding environment in stereoscopic (3D) mode and, simultaneously, to capture a higher resolution stereoscopic images to analyze scientific cases. If mounted on a planetary rover, BIPS merge engineering stereoscopic capabilities for autonomous driving with an optical stereoscopic channel for scientific purpose, making it a new paradigm in the planetary rovers' framework. The operational aims include the identification of boulders, crevasses and other surfaces that can be obstacles for rover trafficability, in addition to the 3D reconstruction of exploration sites for improving situation awareness during both roving and human operations. On the other hand, the correct and detailed 3D reconstruction of exploring sites allows detailed measurements of many geological features such as: sedimentary structures (strata attitudes, geometry and thickness); fracturing networks (attitudes and persistence); folds and faults systems (orientation, vergence and displacement); veining systems (frequency, orientation and thickness); mounds, vents and ridges (slope and aspect); boulders (size frequency distribution). All these measurements are pivotal for the understanding of tectonic, sedimentologic, volcanic, erosive, fluid-rock interaction and impact processes on planetary surfaces. In this paper we describe the optical characteristics of a BPL, the realized terrestrial BIPS, the stereoscopic calibration and some possible scientific cases within the lunar exploration framework.

The quantity, quality, and type of available datasets on Mars have improved in the last couple of decades. Context Camera (CTX) (Malin et al., 2007) on board the NASA Mars Reconnaissance Orbiter (MRO) provides a global coverage with an average resolution of 6 meters/pixel while the High Resolution Imaging Science Experiment (HiRISE) on board MRO (McEwen et al., 2007) allows up to 30 cm/pixel analyses at the local scale. These data allow at places also the DTM generation, but extensive topographic reconstructions at an average scale of 50 meters/pixel are possible using the High Resolution Stereo Camera (HRSC) on board of ESA Mars Express (MEX) (Neukum et al., 2004). Moreover compositional constraints can be provided by the spectral data coming from Observatoire pour la Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) on board MEX and from Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board the NASA Mars Reconnaissance Orbiter (MRO) (Murchie et al., 2007). These relatively recent datasets coupled with the older datasets and Geographical Information Systems (GIS) provide an impressive suite of tools to develop meaningful planetary geological maps. In principle, these new data allow to add to the traditional geomorphological or chronostratigraphic mapping approaches, also a geological map approach somewhat akin to the one well-known on Earth, although, a ‘true’ geological map should be based on the lithological characters of the mapped units; using tone, texture, absence/presence of sedimentary structure, and, if possible, compositional hints to define the units, may represent an adequate ‘planetary perspective’, obviously in addition to the stratigraphic position within the succession. This map approach has the advantages to be relatively objective (and so potentially more useful for geological context analyses) and to represent the stratigraphic complexity within a region. This approach is complementary to the more interpretative (because it includes the processes/environments of formation of the different features) one of the geomorphological maps, which has the obvious advantage to describe the environments/processes active in the region. In the framework of the GMAP (Geologic MApping of Planetary bodies) project, we present here an attempt to merge these two cartographic products taking advantage of GIS-based tools. Moreover, we aim at testing, where possible, the Earth-born symbols designed for the Geological Map of Italy (ISPRA, 2009, 2018) to try to make the ‘language’ of geological maps as uniform as possible. In order to perform these analyses, we selected a series of putative fluvio-lacustrine landforms located in Holden crater, along the south-eastern inner rim (coordinates 26.9°S-33.5°W). The geological map allowed to distinguish several units separated by unconformities. In particular, the Impact unit, equivalent to the one recognized by Tanaka et al. (2014) is nonconformably covered by the materials located inside the crater and along the crater rim. These materials can be distinguished in two groups separated by a disconformity, the first characterized by a relatively large lateral extension of the units and the second by a scattered appearance of the units. Within the first group, a disconformity separates a lower part from the upper part of the succession. The geomorphological map allows to genetically interpret these units, defining: i) a first impact stage, correspondent to the emplacement of Holden crater, ii) a ‘water-related’ phase (correspondent to the lower group of the geological map), and iii) an aeolian phase made of mega-ripples and dunes (correspondent to the upper group of the geological map). The ‘water-related’ phase can be further divided in a fluvio-lacustrine and a glacial phase. We propose the realization of a unique geologic and geomorphologic product that includes a polygon layer with the geological units map described above, a linear layer with the unit contacts (i.e., stratigraphic characterization), and a linear shapefile with tectonic features and geomorphological interpretations. The polygonal units’ layer might be also suitable to subdivide the units in lower-order ranked units, using appropriate fields (i.e., formation/members on Earth). This approach might be best suited for projects developed at the local scale, similar to what is done on Earth, while a chronostratigraphic approach is more fitting and recommended at the regional and global scale. We will identify a possible set of graphical symbols describing the surface features, locating potential limits in current GIS symbology implementation. The GMAP project represents an opportunity to share our experience and to collect current practices in planetary and terrestrial geological and geomorphological mapping, identifying what elements are still lacking and need to be discussed or developed. References ISPRA (2009) - Carta Geologica d’Italia. Guida alla rappresentazione cartografica. Modifiche e integrazioni ai Quaderni 2/1996 e 6/1997. Roma, pp. 166 ISPRA (2018) - Carta Geomorfologica d’Italia. Guida alla rappresentazione cartografica. Modifiche e integrazioni al Quaderno 4/1994. Roma, pp. 95 Malin, M. C., J. F. Bell, B. A. Cantor, M. A. Caplinger, W. M. Calvin, T. R. Clancy, K. S. Edgett, L. Edwards, R. M. Haberle, and P. B. James (2007), Context camera investigation on board the Mars Reconnaissance Orbiter, Journal of Geophysical Research: Planets(1991–2012), 112(E5). McEwen, A. S., E. M. Eliason, J. W. Bergstrom, N. T. Bridges, C. J. Hansen, A. W. Delamere, J. A. Grant, V. C. Gulick, K. E. Herkenhoff, and L. Keszthelyi (2007), Mars reconnaissance orbiter’s high resolution imaging science experiment (HiRISE), Journal of Geophysical Research: Planets (1991–2012), 112(E5). Murchie, S. et al. (2009), Evidence for the origin of layered deposits in Candor Chasma, Mars, from mineral composition and hydrologic modeling, Journal of Geophysical Research: Planets, 114, E00D05, doi:10.1029/2009je003343. Neukum, G, R Jaumann, and H. the and Team (2004), HRSC—The High Resolution Stereo Camera of Mars Express, European Space Agency Special Publication, SP-1240, 17–35. Tanaka, K., J. Skinner, J. Dohm, R. Irwin, E. Kolb, C. Fortezzo, T. Platz, G. Michael, and T. Hare (2014), Geologic map of Mars, USGS Scientific Investigations Map 3292, doi:10.3133/sim3292.

Pit chains commonly occur along a bounding fault, allowing to infer a genetic relationship between grabens and pits. In this work we propose a comprehensive model for the formation of pit chains , the complex sequence of rift system and troughs in Noctis Labyrinthus. Like other previous authors, we confirm that a volcano-tectonic activity is the main process controlling the generation of such interesting and intricate structures in the studied area. We analyzed the geometrical properties and the maximum displacement as a function of fault length and cumulative frequency of fault length distribution for 499 mapped faults, which reveal the host lithology of the faults and the arrangement of rocks in of the crust and the lithosphere. We finally suggest a model where a relative sequence of events responsible for the formation and development of the scalloped network of troughs in Noctis Labyrinthus (Mège et al.,2003).In this model, the magma propagates from depth to the surface by exploiting a network of interconnected fractures, and as a consequence, this magma inflation generates the formation of dike-induced grabens and pit chain on the surface. Introduction Noctis Labyrinthus is one of the enigmatic area in the surface of Mars.This area is made up by a complex inter-connected network of canyons and branched extensional faults and grabens Fig.1.These particular features of unknown origin, make Noctis Labyrinthus an interesting target to understand the possible factors that control the formation of these complex grid of troughs and infer the possible fault system evolution. We performed a detailed qualitative and quantitative study of these faults system through the study of their geometrical properties and surface morphology in order to understand their mechanical evolution and variations over different scales of length, the mechanisms of growth and the related stress field. We measured the maximum displacement as a function of faults length. The Dmax/L diagram provides slightly different results according to the fault type, since this ratio change from normal, thrust, and strike slip faults, so it provides information about the possible nature of the faults in the selected area (Seog Kim et al., 2005). The cumulative frequency plot Fig.3 was used to infer the scaling law of the fault system and faults growth, determine the lithology of the faulted rocks, the arrangement of materials in the subsurface and also the vertical confinement of faults vs. penetration of the brittle crust (Sornette.,2009; Torabi and Berg., 2011;Sornette et al., 1993; Cowie et al., 1991). Fig.1.Surface interconnection between faults and pit chains, which follow a linear trend. Faults sizes and colors are labeled on the graph. 1. Data and methods In our work, as a basemap, we used two orthoimages H3210_0000 and H3221_0000 from High Resolution Stereo Camera (HRSC) on board Mars Express, bearing a resolution of 12.5 m/pixel and for the surface topography, we utilized an individual Digital Elevation Model (DEM) from Mars Orbiter Laser Altimeter (MOLA) on board Mars Global Surveyor, with resolution of ~460 m/pixel. With these data sets, we made all morphometric measurements required for characterizing the faults and the grabens systems, analyzing faults distribution using rose diagrams, measuring faults lengths and the maximum vertical displacement of faults population and carry out a DMax Vs. L diagram and a cumulative frequency plot by input data in Origin software. Afterward, we studied the relationship of those fractures in terms of the formation and evolution of Pit chains and troughs. 2. Discussion and Conclusion Noctis Labyrinhus is a framework of intricate rifts systems and branched faults, that have coalesced together to form an interconnected topography characterized by large troughs and canyons, driven by an invariant extensional stress field. Fault grow and develop at the same way but at different scales (Schultz et al., 2000; Turabi and Berg., 2011). Crustal-Scale linkage in localized faulting zone is responsible for the formation of rift segment border by a pre-existing fracture (Soliva and Schultz., 2008). So far, only a few locations on Mars, where the DMax/L relationship has been measured. In our work, the nonlinear distribution in the Fig.2 might be explained by the presence of small size fractures, with different depths, which could be one of reasons that affect the large distribution of measurements in the Displacement-Length diagram (Turabi and Berg., 2011), or alternatively, it could be linked to the brittle crust thickness that control the displacement and the length of faults as in the terrestrial analogues faults systems (Soliva and Schultz., 2008; Schultz and Fossen.,2002; Soliva et al., 2005; Comie., 1998). Fig.2. DMax /L diagram of faults studied in this work, shows a large scattering of values. The different DMax /L limits are plotted in various lines with different colors. Topographic offsets was measured along single MOLA tracks. The cumulative frequency Vs. Length of fault population values grows in exponential fit Fig.3 of size distribution, mainly reflecting the presence of layered sequence of massive basalt (R.Soliva and R.Schultz., 2008). Fig.3.The cumulative size distribution of the fault length population with Exponential and Power Law fits. On the diagram, the Exponential function fits the most with the main trend. Furthermore,We classified pit chains as a morphological features of volcanic collapse generated by pressure drop above dikes (Mège and Masson., 1996; Liu and wilson., 1998; Scott et al., 2000; Mège and Masson., 1996; Wilson and Head., 2002; Ernst et al., 2001; Mège et al.,2003).Dikes play an important role to connect the surface to the magmatic source. The magma chamber at depth continuously generate flow that will be transported later to the upper levels through the dikes (Mège et al.,2003). This procedure will produce a stress in the dike tip, followed by deflation causing the collapsing of the surface, where there is a graben already formed. This sequence of events is responsible for the generation of the pit chain.We are suggesting a model based on a coupled physical processes of an early extension, visible on the surface by a forked grid of faults and grabens and a magma plumbing. Acknowledgements This research has been supported by European Union’s Horizon 2020 under grant agreement N° 776276-PLANMAP.

Introduction Grooves represent the evidence of tectonic activity that deformed Ganymede surface during its geologic evolution and may have played a key role in the possible connection between surface and the subsurface ocean. In this context, the analysis of Ganymede deformed surface could provide hints regarding its interior, as well as its ice shell’s mechanical behaviour. Indeed, faults distribution and fault populations on icy satellites can reveal insights into the evolution of their surface that cannot be gained with other techniques. In particular, statistical characterization of fault-population attributes, such as length and clustering, are fundamental means to explore deformation rates, stress transmission modes, rheology of the medium, and mechanical layering [1,2,3,4,5]. The fractal analysis has been used in terrestrial planets studies to determine the thickness of the fractured crust [e.g., 6,7,8]. In the same fashion, on icy satellites the exploration of the depth at which fractures penetrate the icy layer could be constrained investigating the main characteristics of fault populations, such as length size-distribution and clustering [9]. In this work, we analyse the grooves’ length and spatial distribution to estimate the potential thickness of the icy crust above the deep ocean required to develop densely populated structures at the surface of Ganymede (i.e. the grooves). Dataset and Methods Our analysis is based on the regional scale grooves mapping [10] that represents a useful dataset to improve the knowledge of the tectonic evolution of the satellite and to recognize the main characteristics of these features. Thanks to these comprehensive grooves mapping dataset, we were able to select four different type-regions located on the equatorial belt of Ganymede. The choice is based on the high density and homogeneous spatial distribution of the grooves located on those regions, which is necessary for the following analysis. The four datasets are in selected regions located in Uruk Sulcus, Babylon Sulci, Phrygia Sulcus and Mysia Sulci, respectively. We investigate the main characteristics of Ganymede’s grooves populations on the four different areas analyzing i) the grooves length distribution to describe the propagation and growing evolution of the faults underlying grooves systems. and ii) the grooves self-similar clustering to infer their vertical penetration inside Ganymede icy shell. Results and Discussion From the length distribution analysis, we found the presence of both an exponential and power-law trends reflecting the possible coexistence of (i) distributed fault systems, with strain regularly partitioned along evenly spaced faults and confined within specific mechanical layers in the crust (exponential fitting curve/curves) and (ii) localized fault systems, with few large faults cutting across the whole crust (power-law fitting curve) [e.g., 2,4]. From the self-similar clustering analysis, we estimated the potential thickness of the icy crust ranging between 105 and 130 km for the datasets considered. This value agrees with independent estimates of the thickness of the icy shell (from 80 to 150 km, [12,13,14]). Hence, our results support the hypothesis of shorter structures vertically confined in different mechanical layers within the icy crust and few very long faults propagating down to the liquid ocean underneath. Acknowledgements The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References [1] Benedicto, A et al. (2003), Geophysical Research Letters, 30, 20, 2076. [2] Soliva, R., and Schultz, R.A., (2008), Tectonics, 27, TC2003. [3] Gudmundsson, A., et al. (2010), Journal of Structural Geology, 32, 1643-1655. [4] Schultz, R.A., et al. (2010). In: Planetary Tectonics, Cambridge University Press, 457-510. [5] Gudmundsson, A., et al. (2013), Tectonophysics, 608, 1298-1309. [6] Mazzarini F., D’Orazio, M. (2003), Journal of Volcanology and Geothermal Research, v. 125, p. 291-305. [7] Mazzarini, F., (2004), Geophysical Research Letters, v. 31. [8] Mazzarini, F., Isola, I. (2010), Geosphere, v. 6, p. 567-582. [9] Lucchetti, A. et al.,. (2017), Icarus, 297, 252-264. [10]Rossi, C. et al., (2020) Journal of Maps. [11] Collins, G.C., et al., 2013. Global geologic map of Ganymede: U.S. Geological Survey Scientific Investigations Map 3237. [12] Schenk, P.M. (2002), Nature, 417-419, 21. [13] Kivelson, M.G. et al., 1996. Nature, 384, 537-541. [14] Saur, J. et al., 2015. JGR Space Physics, 120, 1715-1737.

Virtual Reality (VR, with headsets) and Augmented Reality (AR, using a smartphone or tablet) coupled with 3D photogrammetric reconstructions are increasingly used for science, education and outreach applications. These techniques are not new [e. g. 1, 2], but they are becoming progressively more widespread thanks to the release in 2016 of technologically mature and cost-effective hardware solutions accessible to the general public. In the field of planetology, VR and AR theoretically allow the possibility to simulate field trips to remote places that are otherwise inaccessible to humans. Using high-resolution imaging, coupled with spectral or morphological data gathered by robotic explorers (orbiters, landers, rovers), we can create integrated virtual environments that accurately represent the surface of planetary bodies and allow the cross-comparison of different datasets. These virtual environments provide the possibility to navigate on a global scale using orbital data, and move down to the surface when in situ data are available to visualize and analyze local outcrops. This is particularly the case of the Moon and Mars, where both extensive remote and groundtruth data are available [3, 4, 5]. We are investigating how the information from various sources can be combined in a comprehensive way to display, manipulate, analyze and share both analytical data and results. We have for example integrated visible high-resolution imagery, digital elevation and outcrop models, geomorphological maps and compositional maps derived from spectroscopic measurements on several test sites such as the Copernicus crater and Apollo 17 landing site on the Moon, the Crommelin crater and Kimberley area (Gale crater) on Mars, and the Hokusai quadrangle area on Mercury. The VR and/or AR rendering of simple orbital and/or ground-based 3D models can be performed using a web-based solution such as Sketchfab (e.g. https://sketchfab.com/LPG-3D or https://sketchfab.com/planmap.eu), offering the possibility to visualize, interact, and share medium-resolution 3D versions of these multi-scale data (Fig. 1a and 1b). The use of a more powerful and versatile solution based on a game engine [6] allows the development of more complex solutions, for example dedicated measurement tools (Fig. 1c) or multi-layering capabilities (Fig. 1d). These approaches offer new possibilities in terms of data exploration, analysis, and applications for research and education during “virtual planetary field-trips”. Acknowledgments: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776276 (PLANMAP). References : [1] McGreevy (1993), M.W. Virtual reality and planetary exploration. In Virtual Reality; Elsevier: Amsterdam, The Netherlands,; pp. 163–197, ISBN 0-12-745045-9. [2] Favalli, M. et al. (2012), Multiview 3D reconstruction in geosciences. Comput. Geosci. 2012, 44, 168–176. [3] Ostwald, A.; Hurtado, J. 3D models from structure-from-motion photogrammetry using MSL images: Methods and implications. In Proc. of the 48th LPSC, The Woodlands, TX, USA, 2017. LPI Contribution No. 1964, id.1787. [4] Caravaca, G. et al. (2020) Planet Space Sci, 182, 104808, DOI: 10.1016/j.pss.2019.104808 [5] Le Mouélic, S. et al. (2020) Remote Sensing, 12 (11), DOI: 10.3390/rs12111900 [6] Nesbit, P.R et al. (2020), GSA Today, vol. 30, 4–10. DOI: 10.1130/GSATG425A.1

Future human missions to the surface of the Moon and Mars will involve scientific exploration requiring new support tools to enable rapid and high quality science decision-making. Here, we describe the PANGAEA (Planetary ANalogue Geological and Astrobiological Exercise for Astronauts) Mineralogical Database developed by ESA (European Space Agency): a catalog of petrographic and spectroscopic information on all currently known minerals identified on the Moon, Mars, and associated with meteorites. The catalog also includes minerals found in the analog field sites used for ESA's geology and astrobiology training course PANGAEA, to broaden the database coverage. The Mineralogical Database is composed of the Summary Catalog of Planetary Analog Minerals and of the Spectral Archive and is freely available in the public repository of ESA PANGAEA. The Summary Catalog provides essential descriptive information for each mineral, including name (based on the International Mineralogical Association recommendation), chemical formula, mineral group, surface abundance on planetary bodies, geological significance in the context of planetary exploration, number of collected VNIR and Raman spectra, likelihood of detection using different spectral methods, and bibliographic references evidencing their detection in extraterrestrial or terrestrial analog environments. The Spectral Archive provides a standard library for planetary in-situ human and robotic exploration covering Visual-Near-Infrared reflective (VNIR) and Raman spectroscopy (Raman). To populate this library, we collected VNIR and Raman spectra for mineral entries in the Summary Catalog from open-access archives and analyzed them to select the ones with the best spectral features. We also supplemented this collection with our own bespoke measurements. Additionally, we compiled the chemical compositions for all the minerals based on their empirical formula, to allow identification using the measured abundances provided by LIBS and XRF analytical instruments. When integrated into an operational support system like ESA's Electronic Fieldbook (EFB) system, the Mineralogical Database can be used as a real-time and autonomous decision support tool for sampling operations on the Moon, Mars and during astronaut geological field training. It provides both robust spectral libraries to support mineral identification from instrument outputs, and relevant contextualized information on detected minerals.

Chaotic terrains are broad regions on Mars characterized by the occurrence of angular-polygonal blocks separated by deep fractures and grabens, associated with collapse chains and with the overall mineralogy consisting mainly in basalts (Luzzi et al., submitted, 2020). Several mechanisms of formation for Chaotic terrains were proposed in the literature. While it is a shared opinion that the peculiar structures delineating the polygonal blocks of the Chaotic terrains are due to a collapse, the actual process at the origin of such collapse is still debated. Collapses due to the overpressure within a confined aquifer were proposed (Rodriguez et al., 2005; Andrews-Hanna & Phillips, 2007) as well as related to magma-ice/water interactions (Chapman & Tanaka, 2002; Leask et al., 2006; Meresse et al., 2008), or melting of a buried frozen lake (Zegers et al., 2010). We propose a new formation scenario for Chaotic Terrains: a Chaotic (or Piecemeal) Caldera collapse. In such a Caldera collapse the fragmentation of the floor is irregular and characterized by polygonal blocks. We reproduced this process in a series of analogue experiments similar to those performed by Troll et al. (2002): a rubber membrane was used to simulate the magma chamber with multiple cycles of inflation and deflation that generate the characteristic fractures in an overlying K-feldspar sand layer. We performed the experiments in different settings (different geometry of the magma chamber and different depth) and we found that the geometry of the basin is influenced mainly by the shape of the magma chamber. Moreover, after the second cycle of inflation and deflation, the deformation tends to be moderate, consisting only in the formation of minor fractures and not in deep structures, responsible for the polygonal blocks fragmentation, which are instead formed during the first cycles. From a morphological point of view, the reproduced geometry is strikingly similar to that of Chaotic terrains on Mars. Further quantitative analyses on the DEMs are ongoing in order to assess the role played by each variable and refine a plausible collapse history for the specific case of study of Arsinoes Chaos.REFERENCESAndrews-Hanna, J. C., & Phillips, R. J. (2007). JGR: Planets, 112(E8).Chapman, M. G., & Tanaka, K. L. (2002). Icarus, 155(2), 324–339.Leask, H. J. et al. (2006). JGR: Planets, 111(E8).Luzzi et al. (2020). EarthArXiv, DOI: 10.31223/osf.io/td297Meresse, S. et al. (2008). Icarus, 194(2), 487–500.Rodriguez, J. A. P. et al. (2005). Icarus, 175(1), 36–57.Troll, V. R. et al. (2002). Geology, 30(2), 135–138.Zegers, T. E. et al. (2010). Earth and Planetary Science Letters, 297(3–4), 496–504.

Tsiolkovskiy is a 180 km diameter late Imbrian crater located at 20.4° S, 129.1° E on the far side of the Moon [Whitford-Stark & Hawke, 1982].Compared to the extensive mare deposits present of the lunar side facing the Earth, Tsiolkovskiy crater represents one of the few basaltic exposures on the far side [Pieters & Tompkins, 1999]. Along with its particularly dark and smooth crater floor, the impact crater is also characterized by a morphologically well-shaped central peak on which has been detected both olivine [Corley et al., 2018] and PAN [Ohtake et al., 2009; Lemelin et al., 2015].The area represents thus a potential scientific site of interest for a safe landing. The production of geological maps aiming at characterize Tsiolkovskiy crater will allow the definition of interesting locations for rover exploration.A geomorphological mapping of the crater has been performed using the ~100m/pixel LRO-WAC [Robinson et al., 2010] global mosaic along with the ~59m/pixel LRO-LOLA and Kaguya TC DEM merge which has a vertical resolution of 3-4m [Barker et al., 2016]. The mapping defined six units corresponding to the well-recognizable central peak and the texturally different smooth and hummocky materials constituting the crater floor units, and by scarps with slopes >40°, isolated ponds of smooth material discernible from the rough material constituting the crater rim and constituting the crater walls units.The geomorphological mapping has then been coupled with a spectral characterization of Tsiolkovskiy crater performed on the basis of the ~200m/pixel Clementine UVVIS false color composite (Red 750/415nm; Green 750/1000nm; Blue 415/740nm) [Lucey et al., 2000]. The spectral mapping allowed to discriminate different units characterized by different origin and composition. In particular, the morphologically smooth crater floor unit is composed by fresher basalts and basaltic soils, the steep scarps and the central peak units are mostly composed by norites, troctolites and anorthosites, while the remaining smooth ponds, crater rim and the hummocky crater floor units are generally composed by mature highland soils.In order to define landing ellipses and broad traverses for a rover exploration of the site, the geological mapping is also been supported by an ongoing high-resolution mapping of a quarter of Tsiolkovskiy crater by means of a mosaic of ~0.5m/pixel LRO-NAC [Robinson et al., 2010] images here scaled to 3m/pixel.Finally, a radar investigation for the presence of deep structures will be performed to possibly detect lava pile emplacements and voids in the crater subsoil.AcknowledgmentsThis research was supported by the European Union’s Horizon 2020 under grant agreement No 776276-PLANMAP.ReferencesWhitford-Stark, J.L. & Hawke, B.R., XXXIII LPSC, pp. 861-862, 1982Barker, M.K. et al., Icarus, Vol. 273, pp. 346-355, 2016Pieters, C.M. & Tompkins, S., JGR, Vol. 104, pp. 21935-21949, 1999Corley, L.M. et al., Icarus, Vol. 300, pp. 287-304, 2018Ohtake, M. et al., Nature, Vol. 461, pp. 236-241, 2009Lemelin, M. et al., JGR: Planets, Vol. 120, pp. 869-8878, 2015Robinson, M.S. et al., Space Sci. Rev., Vol. 150, pp. 81–124, 2010Barker, M.K., et al., Icarus, Vol. 273, pp. 346-355, 2016Lucey, P.G. et al., JGR, Vol. 105, pp. 20377-20386, 2000

Geologic mapping is a key element of planetary exploration for mission planning, orbital and rover reconnaissance, and target selection for in-situ analysis and sample return, as well as for understanding the formation and evolution of planetary surfaces. The PLANMAP project (http://www.planmap.eu) aims at produce high-level, standardized geological maps of the Moon, Mars, and Mercury (Massironi M. et al., 2018). The project is integrating different types of data as images, spectral-cubes, chemical data, Digital Terrain Models and three-dimensional geological models to produce geological maps suitable to planetary exploration at different levels. The process results in rich datasets composed by a variety of datatypes encapsulated in open standards and released to the community as freely accessible packages (https://maps.planmap.eu).To accomplish the complexity of deploying PLANMAP packages, considering reliability and automation as key components of a data release workflow, we arranged a data management framework respecting the FAIR (findable, accessible, interoperable, and reusable) guidelines. Geographic data are stored and served by a multi-layered Web-GIS allowing easy information discovery. Particular attention has been paid in designing the user interface and in the definition of the underlying data structure. Different data query services are also provided to properly address different user needs (Luzzi E. et al., 2020). PLANMAP’s datasets can be downloaded in the form of fully contained packages (https://data.planmap.eu) fulfilling a specifically designed standard. Once a data package is ready for publication, validation and summary information extraction take place and the results are published together within the packages.We will here present an overview of the PLANMAP’s deployed data system, and the technical solutions that were adopted with the final goal of improving the quality standards of planetary geological maps.References:- Luzzi E. et al., 2020, “Tectono-magmatic, Sedimentary and Hydrothermal History of Arsinoes and Pyrrhae Chaos, Mars.”, EarthArXiv, doi:10.31223/osf.io/td297- Massironi M. et al., 2018, “Towards integrated geological maps and 3D geo-models of planetary surfaces: the H2020 PLANetary MAPping project”, EGU General Assembly 2018

presented at the "XVI Congresso Nazionale di Scienze Planetarie", Padova, February 2020

Dataset creation, structural analysis and 3D geomodel of the folded deposits within Crommelin crater

International audience; The Curiosity rover's campaign in the Gale crater on Mars provides a large set of close-up images of sedimentary formations outcrops displaying a variety of diagenetic features such as light-toned veins, nodules and raised ridges. Through 2D and 3D analyses of Mastcam images we herein reconstruct the vein network of a sample area and estimated the stress field. Assessment of the spatial distribution of light-toned veins shows that the basin infillings, after burial and consolidation, experienced a sub-vertical compression and lateral extension coupled with fluid overpressure and cracking. Overall, rock failure and light-toned veins formations could have been generated by an overload produced by infilling material within the basin.

Sinuous collapse chains and skylights in Lunar and Martian volcanic regions have often been interpreted as collapsed lava tubes (also known as pyroducts, [1]). This hypothesis has fostered a forty years debate among planetary geologists trying to define if analogue volcano-speleogenetic processes acting on Earth could have created similar subsurface linear voids in extra-terrestrial volcanoes. On Earth lava tubes are well known thanks to speleological exploration and mapping in several shield volcanoes, with examples showing different genetic processes (inflation and overcrusting [1, 2, 3]) and morphometric characters. On the Moon subsurface cavities have been inferred from several skylights in maria smooth plains [4], and corroborated using gravimetry and radar sounder [5, 6] while on Mars several deep skylights have been identified on lava flows with striking similarities with terrestrial cases [7]. Nonetheless, a clear understanding of the potential morphologies and dimensions of martian and lunar lava tubes remains elusive. Although it is still impossible to gather direct information on the interior of martian and lunar lava tube candidates, scientists have the possibility to investigate their surface expression through the analysis of collapses and skylight morphology, morphometry and their arrangement, and compare these findings with terrestrial analogues. In this work we performed a morphological and morphometric comparison with lava tube candidate collapse chains on Mars and the Moon. By comparing literature and speleological data from terrestrial analogues and measuring lunar and martian collapse chains on satellite images and digital terrain models (DTMs), this review sheds light on tube size, depth from surface, eccentricity and several other morphometric parameters among the three different planetary bodies. The dataset here presented indicates that martian and lunar tubes are 1 to 3 orders of magnitude more voluminous than on Earth and suggests that the same processes of inflation and overcrusting were active on Mars, while deep inflation and thermal entrenchment was the predominant mechanism of emplacement on the Moon. Even with these outstanding dimensions (with total volumes exceeding 1 billion of m3), lunar tubes remain well within the roof stability threshold. The analysis shows that aside of collapses triggered by impacts/tectonics, most of the lunar tubes could be intact, making the Moon an extraordinary target for subsurface exploration and potential settlement in the wide protected and stable environments of lava tubes. References [1] Kempe, S., 2019. Volcanic rock caves, Encyclopedia of Caves (Third edition). Academic Press, pp. 1118-1127 [2] Calvari, S. and Pinkerton, H., 1999. Lava tube morphology on Etna and evidence for lava flow emplacement mechanisms. Journal of Volcanology and Geothermal Research, 90(3-4): 263-280. [3] Sauro, F., Pozzobon, R., Santagata, T., Tomasi, I., Tonello, M., Martínez-Frías, J., Smets, L.M.J., Gómez, G.D.S. and Massironi, M., 2019. Volcanic Caves of Lanzarote: A Natural Laboratory for Understanding Volcano-Speleogenetic Processes and Planetary Caves, Lanzarote and Chinijo Islands Geopark: From Earth to Space. Springer, pp. 125-142. [4] Haruyama, J., Morota, T., Kobayashi, S., Sawai, S., Lucey, P.G., Shirao, M. and Nishino, M.N., 2012. Lunar holes and lava tubes as resources for lunar science and exploration, Moon. Springer, pp. 139-163. [5] Chappaz, L., Sood, R., Melosh, H.J., Howell, K.C., Blair, D.M., Milbury, C. and Zuber, M.T., 2017. Evidence of large empty lava tubes on the Moon using GRAIL gravity. Geophysical Research Letters, 44(1): 105-112 [6] Kaku, T., Haruyama, J., Miyake, W., Kumamoto, A., Ishiyama, K., Nishibori, T., Yamamoto, K., Crites, S.T., Michikami, T. and Yokota, Y., 2017. Detection of intact lava tubes at marius hills on the moon by selene (kaguya) lunar radar sounder. Geophysical Research Letters, 44(20). [7] Cushing, G.E., 2012. Candidate cave entrances on Mars. Journal of Cave and Karst Studies, 74(1): 33-47