Orals: Thu, 1 May | Room -2.93
The Mawrth Vallis region is a cornerstone in our understanding of the role of liquid water on early Mars [e.g. 1], which is vital for our knowledge of the evolution of terrestrial planets, planetary habitability and the search for life elsewhere in the Solar System. Here, over 200 metres of phyllosilicate-bearing stratigraphy is exposed, recording extensive and prolonged aqueous alteration during the Noachian period [2]. In the Chryse Planitia lowlands north of the plateau, >14,000 kilometre-scale hills, mesas and buttes (‘mounds’) have been identified as remnants of a larger deposit [3]. However, the geological relationship between these mounds and the highlands remains unexplored.
Employing a novel “topography stacking” method and hyperspectral analyses in tandem with traditional stratigraphic remote sensing observations, we demonstrate that the mounds are erosional remnants of the Mawrth Vallis highland plateau, formed as the plateau receded over time. This finding reveals that the highland plateau extended hundreds of kilometres further north into Chryse Planitia in the Noachian, with the dichotomy escarpment retreating significantly over geological timescales.
There is substantial lateral and stratigraphic geochemical variation within the mounds. Plateau-distal mounds and deeper sections of the stratigraphy contain Mg-rich smectites (e.g. saponite), whereas plateau-proximal mounds and shallower sections are dominated by Fe-rich smectites (e.g. nontronite) that more closely resemble the Mawrth Vallis plateau. These compositional trends indicate differential alteration histories influenced by local environmental conditions.
The phyllosilicate geochemistry of the deepest altered mound strata resembles that of the clay-bearing plains [4] in nearby Oxia Planum—the future landing site of the ExoMars Rosalind Franklin rover [5]—suggesting that the alteration processes influencing Oxia Planum may have operated across a wider geographic area. Thus, by exploring these plains, Rosalind Franklin will also investigate aqueous environments that existed across broader regions of Noachian Mars than those preserved in the landing site.
Furthermore, the aqueous mound succession is interposed above a basal mafic unit (the first observation of unaltered material stratigraphically below the circum-Chryse phyllosilicate sequence [6]), and unconformably below a thin, spectrally bland capping layer. The mound sequence records a transition from early dry conditions through prolonged aqueous alteration to a final phase of non-hydrated deposition, documenting a near-complete stratigraphic history of aqueous conditions in the region.
Our findings highlight these mounds as an archive of early martian geologic history, chronicling the emplacement, alteration, and erosion of the circum-Chryse phyllosilicate deposit. The chemostratigraphical records preserved here provide new insight into the retreat of the dichotomy escarpment, the potential existence of a northern ocean in the Noachian, and the planet’s early habitability potential.
References
- Bishop et al. (2008). Science 321, 830–833
- Loizeau et al. (2012). Space Sci. 72, 31–43
- McNeil et al. (2021). Geophys. Res. 23, e2020JE006775
- Mandon et al. (2021). Astrobiology 21, 464–480
- Vago et al. (2017). Astrobiology 17, 471–510
- Carter et al. (2023). Icarus 389, 115164
How to cite: McNeil, J., Fawdon, P., Balme, M., Coe, A., Cuadros, J., and Turner, S.: Coupled dichotomy retreat and aqueous alteration on Noachian Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8533, https://doi.org/10.5194/egusphere-egu25-8533, 2025.
Pitted cones are widely distributed on Mars, with a particularly high density in the northern plains, including southern Utopia Planitia, Isidis Planitia, and Acidalia Planitia. Pitted cones are small-scale conical landforms characterized by circular or elliptical craters at the top, with clearly discernible flanks and distinct boundaries. Their basal diameters range from 200 to 1000 meters, where the pit diameter is about half the basal diameter and their heights are typically in the tens of meters. Previous studies suggested that their formation may be linked to volcanic, sedimentary volcanism-related, or periglacial processes.
In this study, we identified flow features and rough units spatially close to pitted cones in southern Utopia Planitia. We investigated the spatial and temporal associations between the flow features, the rough units, and the pitted cones with high-resolution orbital imagery from CTX at 6 m/pix, HiRISE at 25-50 cm/pix, and topographic data at ~1 m/pix from HiRISE. The THEMIS-nighttime infrared images at 100 m/pix were used to identify the superpositions of pitted cone fields and impact craters.
Our preliminary findings reveal that the flow features exhibit tongue-shaped lobes on the flanks of pitted cones, sometimes located in the pits, and can form continuous aprons at the foot of the cone. These tongue-shaped lobes are tens of meters in both width and length, while the continuous aprons are shorter in length and yet extend over hundreds of meters in width. Using morphometric analysis, we are investigating whether these flows could originate from volcanic or volatile-driven processes (e.g., lava-ice interactions or mudflows). At the bottom of pitted cones, the apron flows contact the rough units, which are characterized by a rougher surface texture and numerous platy-polygonised ridges. The rough units spread over hundreds of kilometers on the ground, covering a large number of impact craters, meanwhile some small impact craters are superimposed on the rough units. We derived the Absolute Model Ages of pitted cone fields and rough units based on the Crater Size-Frequency Distribution. The results suggest that the pitted cones started to form before the emplacement of the rough units.
This research enhances our understanding of Martian geology and highlights the potential of pitted cones as markers for exploring Martian volcanic or/and volatile history and assessing its astrobiological potential.
How to cite: Zhang, C., J. Conway, S., and Liu, Y.: Flow features potentially related to pitted cones in southern Utopia Planitia, Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8518, https://doi.org/10.5194/egusphere-egu25-8518, 2025.
Oxia Planum, Mars, is the future landing site of ESA’s ExoMars Rosalind Franklin rover (EMRF, launching 2028), which will search for physical and chemical biosignatures at the surface and subsurface using its analytical suite of instruments, the ‘Pasteur’ payload [1]. Oxia Planum contains detections of deposits containing hydrated silica (SiO2·nH2O; opal [2]). Hydrated silica is important in understanding aqueous processes and habitability on Mars owing to its numerous formation pathways which invariably require liquid water, and its excellent preservation potential for physical and chemical biosignatures that may be present.
CRISM data indicate the presence of opal-bearing material (hydrated silica unit; HSU) in two main physiogeographic locations within Oxia Planum. Firstly, HSU is present in a thin (~5 m), bright-toned, blueish-white unit positioned stratigraphically below the sedimentary fan, and above the phyllosilicate-bearing plains. The fan body also contains exposures of meter-scale, laterally-discontinuous outcrops of bright-toned, similarly-colored strata. CaSSIS CBRCs indicate that these outcrops are identical in color to the CRISM detections of HSU in the larger, exposed outcrops. This, as well as their similar relationship to the fan, indicates that they are likely to also be HSU. Outcrops of HSU are also present infilling topographic lows south of the sedimentary fan, at the margins of Pelso Chasma.
The position of the 1.4 µm and 2.2 µm BDR values from targeted CRISM cubes indicate that the HSU in Oxia Planum is predominantly amorphous (Opal-A); ten out of fourteen spectra plot within the Opal-A field, three plot within the crystalline opal (Opal-CT) field, and one plots in the overlap region. The mean crystallinity of opal in Oxia Planum is similar to the mean crystallinity of opal in fans elsewhere on Mars. CRC values for the 1.4- and 1.9- micron features both indicate that opal in the HSU is predominantly weathering-derived, instead of hydrothermally-derived.
Aqueous alteration of hydrated silica under martian conditions can alter its crystallinity through dissolution and reprecipitation by circulating fluid, over time converting relatively more amorphous opal (Opal-A) into relatively more crystalline opal (Opal-CT; [3]). The observation of Opal-A at Oxia Planum, situated directly above clay-bearing plains that underwent aqueous alteration [4], implies an unconformity exists between the alteration of the clay-rich plains and the deposition of the overlying hydrated silica-bearing unit, and therefore also between the plains and the sedimentary fan.
References: [1] Vago et al. (2017) Astrobio. 17, 471-510; [2] Quantin-Nataf et al. (2021) Astrobio. 21, 345-366; [3] Sun & Milliken (2018) GRL. 45, 10,221-10,228; [4] Mandon et al. (2021) Astrobio. 21, 464-480
How to cite: McNeil, J., Grindrod, P., Tornabene, L., and Fawdon, P.: Hydrated silica in Oxia Planum, Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20468, https://doi.org/10.5194/egusphere-egu25-20468, 2025.
Secondary impact craters (“secondaries”) are produced during the excavation stage of the cratering process, from material ejected from the primary crater. Assuming that secondaries can be associated with their primary crater, and that the age of the primary crater is known, secondary crater populations could be used as absolute stratigraphic markers. Using secondary craters to indirectly date distant features is not a new method – it was used during the Apollo missions, to determine the ages of both the Copernicus and Tycho impact events. In this work, we exploited the martian secondary crater population as absolute stratigraphic markers, to make new insights into the evolution of lobate debris aprons (LDAs).
LDAs are landforms found in the martian mid-latitudes and associated with the presence of past and present near-subsurface ice. It is suggested that these morphologies are the results of the flow of a mixture of ice and debris, which derived from the sensitivity of near-surface ice to fluctuations in climate conditions. LDAs are inferred to have formed in the Late Amazonian. However, age constraints of LDA formation are characterized by large uncertainties due to their complex history of modification by viscous deformation, and degradation by erosion, and ice sublimation. Currently, the LDA rate of deformation is considered extremely slow, if not zero, as there is no evidence for crater deformation.
In this work, we exploit the crater population at two LDAs in Tempe Terra and adjacent plain terrains, in the northern hemisphere of Mars. This region is affected by secondary impact craters derived from the primary Maricourt crater, which itself likely formed ~11 Ma. Therefore, LDAs and adjacent terrains in Tempe Terra constitute an ideal site where to extract a range of morphometric parameters through which we aim to assess the downslope deformation of the craters, distinguishing between primary and secondary craters, and discuss the results in terms of their meaning regarding sublimation-related changes and LDAs flow.
We show that 1) for most of the craters, the orientation of crater elongation is concordant with the LDA slope direction; 2) crater elongation is independent of the slope; however, 3) primary and secondary craters have distinctive depth-to-diameter ratios.
How to cite: Magnarini, G. and Grindrod, P. M.: The deformation of lobate debris aprons revealed by crater morphologies in Tempe Terra, Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8494, https://doi.org/10.5194/egusphere-egu25-8494, 2025.
The dwarf planet Pluto was flown over by NASA’s New Horizons spacecraft in July 2015, providing a unique opportunity to study some of its geomorphological features. Photos taken during the flyby revealed kilometer-scale regular bedforms on the nitrogen ice surface of Sputnik Planum. Contrary to their interpretation as sedimentary dunes [1] or ice penitentes, we demonstrate that their formation is due to a hydrodynamic instability associated with the coupling of nitrogen ice sublimation and turbulent heat mixing.
The modulation of the temperature field controls the sublimation rate of the ice surface. In turn, the bed elevation profile influences the modulation of the turbulent flow [2], generated by the thermodynamic imbalance of Sputnik Planum, and thus the advection-diffusion of heat. We show that the pattern wavelength is selected by a transitional value of the Reynolds number, similar to dissolution patterns [2]. The pattern observed on Pluto, with a wavelength of a fraction of a kilometer, is therefore analogous to meter-scale sublimation waves on the Martian north polar cap [3]. Estimates of atmospheric parameters (wind shear velocity, viscosity, temperature, and heat flux from the atmosphere to the surface) accurately predict the observed wavelength. This sublimation instability contrasts with that of penitentes, which is due to the self-illumination of the surface.
[1] Telfer et al., Dunes on Pluto, Science 360, 992-997 (2018).
[2] Claudin, Durán & Andreotti, Dissolution instability and roughening transition, J. Fluid Mech. 832, R2 (2017).
[3] Bordiec et al., Sublimation waves: Geomorphic markers of interactions between icy planetary surfaces and winds, Earth-Science Reviews 211, 103350 (2020).
How to cite: Jia, P., Andreotti, B., and Claudin, P.: Sublimation dunes on Pluto, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3595, https://doi.org/10.5194/egusphere-egu25-3595, 2025.
Hyper-velocity meteorite impacts on planetary surfaces give rise to craters whose morphology evolves under the influence of external factors such as atmospheric processes, as well as internal factors including tectonics and metamorphism. On Earth erosion processes related to climate, such as water, wind, and glaciers, gradually erase these topographic anomalies, or even bury them, while tectonics and other internal processes can play a role too. Nevertheless, the geophysical signature of impact structures often remains preserved, even after hundreds of millions of years.
In this study, we model the morphological evolution of terrestrial impact craters to derive their associated gravimetric signatures. We explore different models for impact craters evolution in terms of regional erosion rate, size and geological composition using landlab landscape evolution model. Our models account for erosion and displacement of sediment by fluvial and hillslope processes, as well as lithospheric flexure. In addition to the landlab simulations, we computed the gravimetric anomaly disturbance throughout the evolution. Theoretical morphologies of complex impact craters with diameters ranging from approximately 10 to 50 km are used and placed under different lithological and climatic conditions.
Unlike previous studies, our approach explicitly takes into account the physical processes driving erosion and sediment deposition. We observe that, for some cases, there is an increase in the amplitude of the negative gravimetric disturbance, and that the extent of the central gravity anomaly may be smaller than the potential rim of the final impact structure.
Our goal is to identify reliable markers which could be used for the systematic detection of impact structures, the assessment of their initial size, and the characterization of their evolution. Indeed this approach will also help to better differentiate impact structures from other geological structures as well to improve our understanding of post-impact processes and their long-term influence on planetary landscapes.
How to cite: Ait Oufella, L., Quesnel, Y., Godard, V., and Lagain, A.: Morphological and geophysical evolution of terrestrial impact craters, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5840, https://doi.org/10.5194/egusphere-egu25-5840, 2025.
Lava tubes are interesting features for their fundamental role in understanding the formation of lava flow fields on Earth and their implication on the emplacement of lava terrains across the solar system and could provide insights into the thermal evolution of rocky planetary bodies. Moreover, being natural shields, they could have a key role in protecting astronauts against micrometeorite impact, space weathering and extreme thermal excursion. For all these reasons, in the last decades, lava tubes have experienced a growing interest as planetary analogues from the scientific community and space agencies. These features have been detected on the surface of Mars and the Moon as sinuous collapse chains, through satellite imagery interpreted as surface evidence of collapsed sections of subsurface conduits (Sauro et al., 2020). Since we have not yet had access to the subsurface of Mars and Moon a direct approach to the analogues will help us to understand what is hidden in the underground of these planetary bodies.
Active lava tubes work as thermally efficient conduits, where the minimisation of heat loss allows the transport of lava flows over long distances (Tomasi et al., 2022), for their origin, three main genetic processes were proposed: overcrusting, shallow inflation and deep inflation (Sauro et al., 2020). It has been recently proposed that the latter forms by magma exploitation of buried weak horizons such as a pyroclastic layer (Sauro et al., 2020; Tomasi et al., 2022). The main two lava tube patterns are single tubes which can be sinuous or rectilinear and braided tubes with splitting branches and reconnections (Sauro et al., 2020). In addition, lava tubes show a huge variety of morphologies and differences in size and shape, potentially associated with their genetic process and specific eruptive (effusion rates, trend and duration of the eruption) and slope parameters.
Thanks to 2D surveys in the regional inventories, it has been shown in karst caves that it is possible to perform morphometric analyses, extracting several dimensional parameters and indices (Piccini, 2011). We have applied a similar approach to lava tubes, resulting in a dataset with 27-dimensional parameters and morphometric indices. These analyses have shown how morphometric indices, through a statistical approach, are useful for classifying lava tubes. In particular, the Aspect Ratio, Vertical Range, Area of the Plan Map and Plan Length have highlighted the relationship between morphologies and genetic processes and the possible evolution of these volcanic caves.
Acknowledgments:
This study was carried out within the Space It Up project funded by the Italian Space Agency, ASI, and the Ministry of University and Research, MUR, under contract n. 2024-5-E.0 - CUP n. I53D24000060005.
References:
PICCINI, Leonardo. Recent developments on morphometric analysis of karst caves. Acta Carsologica, 2011, 40.1.
SAURO, Francesco, et al. Lava tubes on Earth, Moon and Mars: A review on their size and morphology revealed by comparative planetology. Earth-Science Reviews, 2020, 209: 103288.
TOMASI, Ilaria, et al. Inception and Evolution of La Corona Lava Tube System (Lanzarote, Canary Islands, Spain). Journal of Geophysical Research: Solid Earth, 2022, 127.6: e2022JB024056.
How to cite: Marraffa, A., Massironi, M., Pozzobon, R., and Sauro, F.: Morphometric analysis of lava tubes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18326, https://doi.org/10.5194/egusphere-egu25-18326, 2025.
Mass wasting is the downslope movement of rock debris and/or regolith driven by gravity, including falls, slides and flows. It is among the most abundant geomorphological processes in our Solar System contributing to surface evolution on planets, moons, asteroids and comets. On Earth, mass wasting is mostly induced and/or accompanied by liquid water however, on other planetary surfaces, water is at best metastable (i.e., boiling, sublimating and/or freezing). Yet, the distribution of extra-terrestrial mass-wasting features coincides with that of (seasonal) ice and frost. Furthermore, mass wasting frequently occurs well below the angle of repose, suggesting the involvement of fluids or volatiles. While ice sublimation is recognized as a potential mechanism for controlling mass wasting on terrestrial bodies, the effects of gravity remain poorly understood in sublimation-driven mass wasting. This inhibits our ability to identify the effects of gravity and the role of volatiles on the morphology of the deposits, mobility and dynamics of sublimation-driven mass wasting. In new experiments, we attempted to address this critical knowledge gap by generating mass flows driven by CO2 ice sublimation under extra-terrestrial conditions in a cylindrical low-pressure chamber at Open University (Milton Keynes, United Kingdom). We covered the environmental conditions of a broad range of terrestrial bodies, specifically Mercury, Earth, Mars, Ceres, Vesta, Moon, Comets 67P and 9P. Therefore, a step-wise ambient pressure range of 3 to 1000 mbar was implemented. The mass flows were comprised of dry ice and high-density (∼ 2600 kgm−3) or low-density granular material (410 - 1300 kgm−3), the latter was utilized to simulate low-gravity bodies. The experiments reveal that the amount of CO2 gas produced is higher for low ambient pressures, resulting in enhanced pore pressures inside the flow. In turn, the internal particle friction drops, improving the mobility of the mass flows. This effect is more prominent for the low-density mass flows, suggesting that effects of density, i.e., gravity, play an important role in overall fluidization. Additionally, we observe flow behavioural changes at low ambient pressures (≤ 7 mbar). Turbulent CO2 gas bubbles developed inside the flow, causing the granular material to levitate, in turn, enhancing the flow’s mobility. We hypothesize that these fluidization regimes are developed as a result of CO2 sublimation and low ambient pressures. This bubbling appearance will be further analysed using Particle Image Velocimetry (PIV) in more detail.
How to cite: Diamant, S., Conway, S., Roelofs, L., Kleinhans, M., Sylvest, M., Emerland, Z., Patel, M., and de Haas, T.: Effects of gravity in CO2-sublimation driven granular flows in laboratory experiments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2712, https://doi.org/10.5194/egusphere-egu25-2712, 2025.
Sediment settling in water is driven by gravity and resisted by the drag of the liquid the particle has to pass through. In a given liquid, this drag is a function of settling velocity and subject to a complex relationship between particle movement and assocuated hydraulics of the liquid surrounding the particle. On Earth, settling experimets have been used to establish empirical relationships between settling velocity and properties such as particle size, shape and density. These relationships do not apply to conditions where settling velocity is reduced, e.g. because of lower gravity, such as Mars. In this study, the results of settling velocity measurements obtained during experiments on reduced gravity flights are used to assess the impact of reduced gravity on the sorting of sediment in a deltaic environment. The results show that sorting of the fine sand fraction is less pronounced than on Earth. This raises the question inasmuch terrestrial rocks with similar textures than those observed on Mars can be considered as an analogue for Martian sedimentary environments. The potential limitations of such analogues also affect the assessment of Martian sedimentary environments as either past habitats or archive for traces of past life on Mars.
How to cite: Kuhn, N. J., Kuhn, B., Fister, W., and Trudu, F.: Reduced gravity effects on Martian deltaic sediment textures , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1510, https://doi.org/10.5194/egusphere-egu25-1510, 2025.
Deltas on Mars are prime targets for robotic exploration in the search for extraterrestrial life. While terrestrial deltas serve as a framework for interpreting Martian deltas, Mars' lower gravity affects sediment transport, potentially altering delta morphology (Braat et al., 2024). To explore this, we conducted physical experiments to investigate the impact of gravity on autonomous delta formation. By studying differences in delta evolution and morphodynamics between Earth and Mars, we can learn how to better apply our terrestrial knowledge to the Martian landscape.
Physical experiments were conducted in the Earth Simulation Laboratory at Utrecht University in a facility called the Metronome. Water (300 L/h) and sediment (2 L/h) were supplied to a 3 cm-deep flume, where we simulated Martian gravity by reducing sediment density (using nutshell grains, ~1350 kg/m³) without altering grain size. Comparisons are made to deltas with quartz particles (~2650 kg/m³) under otherwise identical conditions, isolating sediment density as a proxy for gravity.
Preliminary results indicate that reduced sediment density produces deltas with gentler slopes, larger surface areas for equal deltas volumes, more irregular coastlines, and different channel dynamics. Simulated Martian channels on the delta appear wider and shallower than their Earth counterparts under equal conditions and stay in place longer. While the data acquisition is being finalized, data analysis is still ongoing. Nonetheless, these findings show great promise to provide insights into how gravity influences delta morphology and improve our ability to apply our knowledge of deltas on Earth to ancient Martian environments.
How to cite: Braat, L. and de Boer, I.: Martian Deltas: Experiments on the Impact of Sediment Density on Delta Morphology as a Proxy for Gravity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8162, https://doi.org/10.5194/egusphere-egu25-8162, 2025.
Posters on site: Fri, 2 May, 10:45–12:30 | Hall X2
Enceladus, Saturn’s sixth-largest moon (diameter: ~504 km) [1], is one of the geologically active bodies of the Solar System. Its icy shell its characterized by linear structures of tectonic origin that are the focus of this study [2]. With this work our intent is to provide an example of methodical mapping and classification of the geomorphological features characterizing the outer shell of an icy satellite.
We mapped the single structures and families of structures – characterized by the same direction and possibly originated in the same tectonic event – at four locations – referred to as ‘areas of interest’ – sit in two out of the four geological provinces identified in [3]. Each area of interest had all the sides measuring 20° and contained one structure already identified. This choice was made to ensure the correct understanding of all the others structures since the study was conducted only using the available Cassini global mosaic (resolution 110 m/px) [4]. The classification method used in this work was the one proposed in [5] with Enceladus’s linear structures falling under five classes: scarp, trough, band, ridge, and chasma.
We managed to identify a total of 69 between single structures and families of structures. They were classified into the aforementioned morphological categories based on their geometric characteristics after an analysis of their cast shadows. Due to the limited resolution of the available data and the absence of an available DTM at the time of the study, 7 of them remained undefined. Among the other 62, the vast majority (56) was identified as falling under the ‘trough’ class (11 of them were additionally sub-classified as ‘pit chains’), whilst 3 of them where chasmata, 1 was a band, and 1 was a scarp. We also managed to sketch a relative timeline for each area of interest by using the cross-cutting relationships existing between the structures. Main and secondary periods were defined to give a better understanding of the tectonic evolution of each area of interest.
Our study, although moderate in its extent, represents a solid attempt at applying a methodical mapping process for an icy satellite. We provided a classification for a number of structures whose class had not yet been defined and theorized a possible tectonic evolution for each area based off the geomorphological cues at our disposal, setting up a possible workflow for future studies on other similar bodies in the outer Solar System.
REFERENCES:
[1] Thomas, P. C. (2010). Icarus, 208, 395–401.
[2] Spencer, J. R. and Nimmo, F. (2013). The Annual Review of Earth and Planetary Science, 41, 693–717.
[3] Schenk, P. M., Clark, R. N., Howett, C. J. A. Verbiscer, A. J., Hunter Waite, J. (2018). University of Arizona Press, 536 pages.
[4] Bland, M. T., Becker, T. L., Edmundson, K. L., Roatsch, T., Archinal, B. A., Takir, D., et al. (2018). Earth and Space Science, 5, 604–621.
[5] Nahm, A. L. and Kattenhorn, S. A. (2015). Icarus, 258, 67–81.
How to cite: Caddeo, Y., Pondrelli, M., and Melis, M. T.: Mapping and Classification of Enceladus’s Linear Structures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18088, https://doi.org/10.5194/egusphere-egu25-18088, 2025.
Exploration with Mars rovers has allowed us to confidently identify and investigate in detail fluvial and lacustrine settings on Mars that were first only hypothesised from orbital data [1]. Identifying the characteristics of fluvial and lake deposits from orbital data is important because it allows those locations with the highest biosignatures preservation potential to be prioritized for future rover missions searching for evidence of past life on Mars. For example, in the 2028 ExoMars Rosalind Franklin Rover mission to Oxia Planum, understanding the fluvial and lacustrine environments feature heavily in interpretation of the landing sites geological history [2,3]. These locations will be key to the mission objective: reconstructing past environmental conditions and understanding the history of water activity and habitability [4].
To prepare for this mission we use NASA’s Rover’s Analyst notebook [5] to collate images taken along the traverses of NASA's Mars Exploration Rovers (MER), Mars Science Laboratory (MSL) and Mars 2020 missions and explore the geological evidence for lacustrine environments and their stratigraphic contacts. Examples include erosional unconformities such as the Murray-Stimson contact [6] and the Jura-Knockfarril Hill [MSL; 7] as well as lake-bed deposits found at Wildcat Ridge [Mars 2020; 8]. We then compare this rover data to orbital remote sensing data (CTX, HRSC, HiRISE and CaSSIS) of those same contacts and their pre-mission interpretations.
This analysis of how the context of fluvial and lacustrine geological units can be identified from orbit is then used to identify locations in Oxia Planum that have the potential to host lacustrine deposits. We then collate and examine those examples that occur within the landing ellipse patterns of the 2028 launch opportunities. These provide exciting target locales that could be explored during the upcoming Rosalind Franklin mission [9].
References: [1] R. M. E. Williams et al. (2013), Science 340,1068-1072 [2] Vago et al. (2024), LPI Contributions 3007 [3] Grotzinger, J. P., et al. (2014), Science, 343(6169) [4] Golombek, M. P., et al. (2012), Space Sci. Rev, 170 [5] NASA’s Planetary Data System, 2025 [6] J. P. Grotzinger et al. (2015), Science350 [7] Fedo, C. M. et al. (2022), JGR Planets, 127 [8] Witze, A., (2022). Nature, 609(7929) [9] Fawdon, P. et al. (2021), Journal of Maps, 17(2).
How to cite: Gor, N., Balme, M., and Fawdon, P.: The application of orbital and rover observations of fluvial and lacustrine environments to the 2028 ExoMars Rosalind Franklin Rover in Oxia Planum., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19218, https://doi.org/10.5194/egusphere-egu25-19218, 2025.
In the eastern part of the Arabia Terra cratered boundary, lobate deposits are observed on top of north-sloping highland mesas. Our previous studies (Rodriguez et al., 2016; Costard et al., 2017) suggest that the most plausible origin for these lobate morphologies are tsunami deposits associated with the Lomonosov impact event in an Hesperian age ocean (Costard et al., 2019). Tsunami deposits on Earth serve as valuable analogs for interpreting possible tsunami-related features on Mars, especially regarding hypothesized ancient oceans. In this study, we examine the 2004 Banda Aceh tsunami terrain in Indonesia (Lavigne et al., 2009) as an analog site to refine our understanding of Martian paleotsunami processes. We employ Volcflow (Kelfoun and Druitt, 2005), a numerical flow simulation tool, along with field-based and satellite observations to analyze tsunami inundation, run-up, and backwash dynamics. Satellite imagery (Lavigne et al., 2009) of the Banda Aceh region reveals sandy lobate deposits with distal ridges, contrasting with fine-grained, smooth deposits extending farther inland. These depositional and erosional features closely resemble potential tsunami-related signatures observed on Mars, including lobate margins, distinctive surface textures, and backwash channels. The backwash channels at both sites display consistent width-to-depth ratios, parallel to sub-parallel orientation, and cross-sectional geometries, providing quantitative support for our interpretation of Martian paleoshorelines.
How to cite: Costard, F., Bouley, S., Kelfoun, K., Lavigne, F., Rodriguez, A., and Sejourne, A.: Morphometric Analysis of the 2004 Banda Aceh Tsunami Deposits as Analogs for Martian Paleotsunami Features, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9022, https://doi.org/10.5194/egusphere-egu25-9022, 2025.
Since the formation of Mars, its environmental conditions have changed. There is multiple and varied evidence that Mars was more similar to Earth at the beginning of its history. To contribute to the knowledge of the early conditions on Mars, it is important to study the geomorphological processes that shaped its surface and the period of time during which these processes operated.
For this purpose, we have selected an area located between highlands and lowlands, in the southwest of Sinus Sabaeus (3ºE, 21ºS and 10ºE, 29.5ºS). This region is composed by a longitudinal valley, named Marikh Vallis, a central plateau, and two large craters with diameters of 198.8 and 121.7 km each, which we named Margulis and Roemer, respectively (IAU approval on April 21, 2021).
To study these geomorphologies, we have included datasets in ArcGis, based on Context Camera images (CTX), with 6/pixel resolution. To obtain age constraints, we used the Crater Size Frequency Distribution (CSFD) counting technique using the "Craterstat" software, developed by the University of Berlin.
The combined geomorphological and crater counting results suggest that the study area has undergone several resurfacing processes consistent with surface modification by liquid water and water ice. These processes also included glacial and periglacial processes, and some modifications due to subsurface water activity triggered by the melting of ice in the shallow subsurface. Most of these processes occurred during the Noachian and the Hesperian periods.
Some of the identified morphologies, such as etched terrains, polygonal terrains, crater ejecta, and some valley types, are compatible with a Noachian to Hesperian origin under glacial and periglacial conditions. This fact is particularly relevant because it means that the studied morphologies may have formed under an icy and wet early Mars, suggesting that Sinus Sabaeus could be considered an attractive Martian location to explore in terms of habitability.
How to cite: G. Fairén, A. and Robas, C.: Origin and age of water-related morphologies in the southwest Sinus Sabaeus, Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9077, https://doi.org/10.5194/egusphere-egu25-9077, 2025.
Periodic bedrock ridges (PBRs) are interpreted as repeating, symmetrical, meter- to decameter-scale linear ridges observed on Earth and Mars [1-6]. In situ and orbital observations of PBRs on both planets suggest that PBRs develop transverse to dominant or long-term winds [7] and are eroded directly into cohesive substrate [5-7]. As a result, PBR orientation can be used as proxies to reconstruct past climatic conditions (i.e. paleowind directions), and their expression on the landscape can lend insight into the environments in which they have formed.
To date, PBR identification and documentation has been largely opportunistic and limited to a single site on Earth in northwestern Argentina [7] and at 11 sites in four regions on Mars: Valles Marineris and the Medusae Fossae Formation [1], the MSL Curiosity landing site at Gale crater [e.g. 2,3], and around the circum-Chryse basin, including at Oxia Planum [4-6], the 2030 landing site of ESA’s ExoMars Rosalind Franklin rover.
A recent study in the circum-Chryse basin [5] noted that PBRs were often found on Fe/Mg phyllosilicate- (clay) bearing terrain. In situ and orbital observations of PBRs at Gale crater have similarly been found to be eroded into Fe/Mg rich clay-bearing materials [2,8]. This raises the possibility that PBRs could be found in other clay-bearing terrains on Mars, and that their formation may be tied to the mechanics of this surface.
Building on these observations, this research investigates PBRs on Fe/Mg phyllosilicate-bearing terrain in an equatorial band between 20° S and 20° N on Mars as detected by OMEGA (Observatoire pour la Mineralogie, l’Eau, les Glaces et l’Activite) and CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instruments [9] onboard ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter, respectively.
A systematic survey of 3922 HiRISE images that overlapped Fe/Mg phyllosilicate signatures from the Mars Orbital Catalogue of Aqueous Alteration Signatures [9] was undertaken in a GIS. We identified 1526 HiRISE where PBRs were either confirmed or necessitated further investigation. From this detailed analysis, we have identified over 350 new sites where PBRs are found. Our investigation to date has revealed a diversity of form, expression, and distribution not currently described in the literature, and will be reported on at this meeting.
Overall, this work investigates the nature of PBRs found on clay-bearing terrain across the equatorial region of Mars to (i) elucidate the controls on distribution and expression on the landscape, and (ii) offer insights into the hydrologic, aeolian, and climate conditions on Mars across vast spatial and temporal scales.
[1] Montgomery et al. (2012). J. Geophys. Res. Planets, 117(E3); [2] Stack et al. (2022). J. Geophys. Res. Planets, 127(6); [3] Bretzfelder et al. (2024). Icarus, 408; [4] Favaro et al. (2021). J. Geophys. Res. Planets, 126(4); [5] Favaro et al. (2024). EPSL, 626,118522; [6] Silvestro et al. (2021). Geophys. Res. Letters, 48(4); [7] Hugenholtz et al. (2015). Aeolian Research, 18. [8] He et al. (2022). J. Geophys. Res. Planets, 127(9); [9] Carter et al. (2023). Icarus, 389.
How to cite: Favaro, E. A., Balme, M. R., McNeil, J. D., Fawdon, P., Davis, J., Grindrod, P. M., Banham, S. G., and Lewis, S. R.: Periodic Bedrock Ridges in the Equatorial Region of Mars: Insights from a Global Study, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18100, https://doi.org/10.5194/egusphere-egu25-18100, 2025.
Aeolian features on Mars, ranging from active granular bedforms to relict cohesive outcrops, reveal the spatially diverse and temporally extensive influence of wind across the planet. Deciphering the climatic signals encoded in these features requires careful consideration of the interaction between the force of the wind and interaction with surface material.
Studies elucidating aspects of the modern wind climate for a particular study site or aeolian feature typically use global circulation models (GCMs) to relate aeolian orientations to modelled wind directionality. However, the efficacy of the modelled data is complicated when one considers that the scale of the GCM output (typically run at hundreds of kilometres) is vastly different than the scale of the study (often tens of kilometres). The scale of GCMs means topographically complex surfaces (valleys, craters, etc.) are unable to be fully accounted for. For these types of studies, higher resolution models – mesoscale models – are necessary.
Our overarching objective is to provide Mars geomorphology researchers with reliable wind data at topographically-relevant scales for use in studies of aeolian features. To evaluate our approach and demonstrate the feasibility and appropriateness of our methodologies, we present our mesoscale modelling outputs against mapped aeolian features at three locations on Mars: Ares Valis (wind streaks), Mawrth Vallis (dunes), and Syrtis Major (wind streaks).
The publicly available Open access to Mars Assimilated Remote Soundings (OpenMARS) dataset [1] provides the initial and hourly-updated boundary conditions for the mesoscale simulations, which were performed using the Laboratoire de Météorologie Dynamique Mars Mesoscale Model [2]. We configured the mesoscale model to run with 40 unevenly spaced levels from the surface up to 50 km. A 3000 by 3000 km domain was evaluated at Syrtis Major at a horizontal resolution of 14 km; a 1000 by 1000 km domain was used at the other four locations at a horizontal resolution of 5 km. At each location, we performed four sets of simulations, each lasting 12 sols and starting at a different time of year (initialised at LS= 0°, 90°, 180° and 270°), to capture seasonal variability. The data from the four simulations were combined and mean eastward and northward winds calculated for each grid point. Given the long formation timescales of some aeolian features studied, we focused on the average wind field over a year.
The results of our modelling efforts in these regions, which show good agreement between modelled outputs and aeolian feature orientation, will be presented. Our analysis demonstrates that this approach will serve as a useful tool for geomorphologists to request and handle reliable mesoscale modelling outputs to interpret aeolian features in terms of present-day or paleoclimate conditions.
[1] Holmes, J. A. et al. (2020) Planet. Space Sci., 188, 104962. [2] Spiga, A. and Forget, F. (2009) JGR-Planets, 114(E2).
How to cite: Favaro, E. A., Patel, M. R., Rajendran, K., and Holmes, J. A.: Decoding Mars' Aeolian Features: Mesoscale Models for Wind and Climate Analysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21389, https://doi.org/10.5194/egusphere-egu25-21389, 2025.
Planetary habitability is driven by interior, surface, and external processes shaping the planet in concerto. To understand planetary habitability in our solar system, it is crucial to compare these planetary processes between its planets and moons and Earth, the only planet we know is habitable. The majority of our insights in solar system bodies is gained through planetary exploration, which in turn is also the way forward to grow our understanding. Through a new Planetary Science Network in the Netherlands, we are going to build on existing solar system expertise in the Netherlands to establish a framework to develop a set of key observables that enable in situ or remote detection of planetary habitability. To develop these observables, we have identified three main themes, planetary interiors, with Ganymede as a case study, surface morphology, focussing on landforms and using Mars as a case study, and surface composition, comparing Earth's oldest and icy surfaces with Mars and icy moons. Through a synergetic approach within the network, the outcomes of the three themes will provide both observables for the case studies and fundamental observables that can be applied to our solar system and the plethora of known exoplanet systems. The main outcomes of the network will lead to further strengthening the position of the Dutch planetary science community and active contributions to instruments for future solar system exploration missions. It will also result in closer collaborations with the strong Dutch exoplanetary science community, aiming to bridge the gap between what should be observed and what can be observed. With our presentation, we would like to introduce our network and research goals to the international community, share ideas and find connections.
How to cite: Roelofs, L., van Westrenen, W., ten Kate, I. L., de Vet, S., de Haas, T., van der Wal, W., and van Ruitenbeek, F.: Netherlands Planetary Science Network on Observables of Planetary Habitability, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20486, https://doi.org/10.5194/egusphere-egu25-20486, 2025.
