ICG2022-25

ICG2022
Planetary Geomorphology 

The Planetary Geomorphology session showcases landscapes and surface processes on solid bodies across the Solar System, including on planets, dwarf planets, moons, comets, and asteroids. The session aims to highlight the diversity of geomorphic processes that have operated on different Solar System bodies through time. This includes fluvial, glacial, periglacial, volcanic, tectonic, aeolian, and impact processes, and their interactions. We encourage submissions on studies that use Earth analogues, laboratory experiments, numerical simulations, remote sensing and/or new techniques to investigate planetary surfaces. We welcome submissions from early career scientists and those who are new to the discipline.

Conveners: Frances E. G. Butcher, David A. Vaz
Orals
| Thu, 15 Sep, 17:00–19:00|Room Sala Sofia-C2B

Orals: Thu, 15 Sep | Room Sala Sofia-C2B

17:00–17:05
17:05–17:20
|
ICG2022-700
David C. A. Silva, David A. Vaz, Gaetano Di Achille, and Laetitia Le Deit

Martian deltaic deposits are good indicators of water distribution and provide insight into the climate evolution of Mars [1]. A notable case is the fan deposit located in Jezero crater, currently being studied by the Perseverance rover. Hydrated silica-bearing deposits were identified in this area [2, 3, 4], and the overall stratigraphy and morphology point to an evolution passing through a progradation and a transgression phase, to an erosion episode [5]. All these evidences suggest that this deposit was formed by fluvio-deltaic activity in an ancient lake basin [6] during the late Noachian or early Hesperian epochs [7]. After its formation, the deposit likely suffered a complex and profound exhumation [8] which we will try to constrain through a mass balance analysis.

Here, we present the first results of a project seeking to understand the depositional and post-depositional evolution of the Jezero delta, including the study of its hydrographic basin [9]. We will focus on a mass-balance survey, analyzing and comparing the volume of sediments that were eroded from the basin and deposited into the crater. We integrate HRSC, CTX and HiRISE data to create a regional DTM and orthophoto map covering the Jezero crater and its drainage basin. These datasets enable us to estimate the volume of sediments eroded from the drainage basin, as well as the present-day volume of the fan deposit. Finally, we will apply the mass balance model introduced by [10], aiming at evaluating putative sediment offshore loss and post-depositional fan erosion. This will allow to infer the initial volume of the deltaic deposit and test different lake water levels.

 

[1] Di Achille, G. and Hynek, B. M. (2010). Nature Geoscience, Vol. 3 (7),459-463. [2] Pan, L., et al, (2021). Planet. Sci. J., 2(2), 65., [3] Horgan, B., et al, (2020). Icarus, 339. [4] Mangold, N., (2007). J. Geophys. Res. 112(8). [5] Goudge, T. A., et al. (2018). Icarus, 301 58–75. [6] Fassett, C. I., & Head, J. W. (2005). Geophys. Res. Let., 32(14), 1–5., [7] Mangold, N., et al, (2021). Science 10.1126, [8] Quantin-Nataf, C., et al (2021). 52nd LPSC, [9] Goudge, T. A., et al, (2015). J. Geophys. Res. Planets 120., [10] Vaz, D. A., et al, (2020). Earth Planet. Sci. Lett., Vol. 533.

How to cite: Silva, D. C. A., Vaz, D. A., Di Achille, G., and Le Deit, L.: Sedimentary mass balance modelling of the Jezero crater fluvio-deltaic system, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-700, https://doi.org/10.5194/icg2022-700, 2022.

17:20–17:35
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ICG2022-574
Francisco Rodrigues, Eusébio Reis, and Pedro Machado

Mars is the most Earth-like planet in the Solar System, due to its formation, structure and composition, but also due to the characteristics of its surface. These particularities point to the fact that, some time in its geological past, the planet was potentially habitable. Two such indicators are the morphological evidence that reveals an active hydrosphere with liquid water flow and the probable ocean existence. The deltaic lobes record possible interactions between watercourses and a potential giant water body on Mars. The goal of this study is to identify and characterize erosion and deposition processes, dominated by watercourses and littoral dynamics, through high-resolution imaging to characterize the shapes on the surface.  Through its morphological features the environmental behaviour of the Borealis Ocean at its interface with the coast was determined, establishing the parallelism with the dynamics observed on Earth.

Based on the literature review, a region of interest was selected that brought together fluvial phenomena and was in a strong dichotomous line. Two geographically close deltas were selected (Abus Vallis and Isara Vallis) that exhibit similar morphological characteristics, revealing that they were formed in the same environment. Abus Vallis appears to be of extreme importance, given its easy dating, as it is covered by units dating to the Late Hesperian (3.6 - 3.3 million years) permitting to temporally locate the Isara delta, which is given special focus. Subsequently, spectral images were used, obtained through the equipment orbiting Mars, specifically Mars Express- ESA, which has an instrument for storing high-resolution images and topographic data (HRSC). To identify and characterize the erosion and deposition processes, the high-resolution images were processed in GIS environment, and the morphology of the study area was identified, characterized and mapped. The results show that the Isara delta is located at the boundary between the northern lowlands and the southern highlands (potential ocean-continent boundary) in the Memnonia. There are two giant promontories (Amazonis Mensae and Gordii Dorsum) with a northwest - southeast orientation in the area, which may have been formed by massive flood events that filled the Amazonis Planitia basin with water, which widens and deepens towards the northern plains. This phenomenon was triggered by deformation of the Martian crust by tectonics and hydrothermalism during the development of the Tharsis volcanic shield. According to the analysis of the HRSC images, it was found that the Isara Vallis delta comes from a valley created by ground water sapping, from aquifers that come from Tharsis. The high-resolution images and digital terrain models, reveal that the studied delta is a Gilbert-type, stepped, shallow-water delta with a dug main fan channel, which witnesses different mean water levels from the receiving basin. This allowed to reconstruct the fluvial and marine dynamics of Mars during the formation of this delta. 

The satellite images allowed the production of very detailed cartography, enabling a better reading of the delta's shapes and characteristics, through which it will be possible to understand the hydrological cycle of Mars, at a regional and global levels.

How to cite: Rodrigues, F., Reis, E., and Machado, P.: Identification and interpretation of morphological evidence associated with fluvial-marine environments on Mars, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-574, https://doi.org/10.5194/icg2022-574, 2022.

17:35–17:50
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ICG2022-402
Deniz Yazici, Cengiz Yildirim, and Tolga Gorum

Kasei Valles is the second largest valley on Mars. This study focuses on landforms created by surface processes in the central part of the southern branch of Kasei Valles. We mapped the landforms and built a morphostratigraphical chronology using numerical crater dating and cross-cutting relationships of the landforms. We interpret that surface processes formed various landforms in the study area, including plateau surfaces, deeply incised canyons, colluvial fans, landslide, topographic barriers, trim lines, terraces and platy-textured valley floor fill. These features aligned within the deeply incised valley of the valles indicating incision of the plateau surface. The most common landforms are colluvial fans. Two colluvial fans and a landslide temporarily blocked the valles, forming topographical barriers to impound fluids (e.g lava, mudflow, water). The trim lines in area may indicate the presence of water like liquid in the valley, even for a short time. Terrace surfaces are very evident between these trim lines. The surface texture of the terrace surfaces implies that they were probably formed by a water-like fluid that stagnated and regressed for a period and fluctuated to carve terrace staircases. Crater statistics reveal two different temporal clusters of colluvial fan formation. The age of the older colluvial fans cluster in the Early Amazonian period (around 1.74 - 1.14 Ga), and the age of the younger colluvial fans cluster in the Late-Middle Amazonian period (around 307 Ma). The landslide is much younger, and it is estimated to have formed 122 Ma before present. The youngest studied geomorphic features are the platy-textured deposits emplaced either as lavas or mudflows, aged 90 Ma, covering the floor of the valles. Our data suggest that the presence of well-developed terraces between trim lines require the presence of a Newtonian fluid (e.g. water) that ponded into the study area and the climatic conditions for this fluid to remain stable over short timescales enough to form terraces.

How to cite: Yazici, D., Yildirim, C., and Gorum, T.: Landscape Evolution of Kasei Valles, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-402, https://doi.org/10.5194/icg2022-402, 2022.

17:50–18:05
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ICG2022-139
Carlotta Parenti, Massimiliano Cadei, Cecilia Fabbiani, Fabio Malagutti, and Sofia Rossi

Project RED started in 2019 at the Department of Sciences and Methods for Engineering of the University of Modena and Reggio Emilia (Italy) as a team of BSc, MSc and PhD students passionate about robotics, aerospace and planetary sciences. Since 2021, the team has included students from the Department of Chemical and Geological Sciences. The objective of Project RED is to design and build a prototype of a rover for extraterrestrial exploration with which to compete in the European Rover Challenge (ERC), an annual international competition based on real ESA and NASA missions. The competition consists in a short traversal of an autonomous rover on the “Mars Yard” (i.e., the ERC competition area simulating a real Martian region) aiming at executing a science-driven exploration based on a coherent geological and geomorphological interpretation of the “landing site” surface. Project RED has participated in the 2021 edition of ERC and is now preparing for 2022 edition of ERC.

To cope with the ERC tasks, the Project RED team comprises divisions of engineering and geology students who carried out different activities, such as the building of the rover and the geological analyses of the Martian surface. In particular, the main activities of the geology students (“Science Division”) aim at reconstructing the geological setting of a surface portion of the planet with particular attention to the analysis of a landing site where a hypothetic rover will be directed. The analysis foresees the characterization of the Martian surface from a geological, geomorphological, chemical and mineralogical viewpoint, recognizing and interpreting the origin of landforms and their chronostratigraphy.

The study area selected for the 2021 edition of ERC was northern Elysium (135-155E, 22-35N), situated in the eastern hemisphere of Mars. The Science Division reviewed existing literature, thematic maps and high-resolution satellite images. All data were analyzed in a Geographic Information System (GIS) environment. Landforms were identified through CTX images and HiRISE images and mapped in a georeferenced system (Mars2000 Equidistant Cylindrical clon0), leading to the production of extracts of geomorphological sketch maps. The results highlighted that the Elysium region has been affected by different geological processes, such as tectonic, fluvial, mass-wasting and volcanic ones associated with channel formation, faulting and volcano/ground-ice modifications. The main geological features found in the study area are: (i) fractures, (ii) narrow linear depressions, (iii) lobate scarps, (iv) rimcrests and (v) impact craters.

These analyses were performed in order to determine and trace the most suitable and safest path to be followed by the rover during the ERC competition avoiding potential obstacles.

How to cite: Parenti, C., Cadei, M., Fabbiani, C., Malagutti, F., and Rossi, S.: Project RED: A challenging student project on space sciences and planetary geology, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-139, https://doi.org/10.5194/icg2022-139, 2022.

18:05–18:10
18:10–18:25
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ICG2022-186
Daniel Le Corre, Nigel Mason, Jeronimo Bernard-Salas, David Mary, and Nick Cox

This presentation for the ICG2022-25: Planetary Geomorphology session of the 10th International Conference of the International Association of Geomorphologists (IAG) aims to describe the purpose, methodology, and testing results of the Martian Pit Shadow extractor (MAPS) tool. The challenges that were faced in its development, particularly in relation to the geomorphology of these features, will also be discussed. MAPS itself is an automated Python framework which employs K-Means clustering to extract the shadow from a cropped red-band Mars Reconnaissance Orbiter HiRISE image of a Martian pit and measure its width.  MAPS also exploits the sensing information provided for each HiRISE image in order to determine the apparent depth (the depth of the pit at the edge of its shadow).  MAPS is intended to be used after a machine learning model, or another automated method, has detected Martian pits in HiRISE imagery, such that it can be applied to cropped images without the need for manual labelling. While MAPS has currently only been applied to Martian pits imaged by the HiRISE camera, its overall method would be highly applicable to data taken by other sensors, or data taken of other planetary surfaces.

Martian pits are circular-to-elliptical geological depressions commonly seen on the surface of Mars, as well as on other terrestrial planetary surfaces. Their morphologies are most distinguishable from impact craters by the lack of an elevated rim. They are generally formed by gravitational collapse into an underground void, or by the evacuation or removal of subsurface material.  Pits are heavily studied for both their geological significance, but also because of their implications on future space exploration. Current methods can calculate the apparent depths of Martian pits by considering the Sun’s position in the sky and manually measuring the widths of their shadows in remote-sensing imagery. However, an automated method of shadow extraction and depth calculation allows for analysis of far larger numbers of Martian pits, which could be used for further research or engineering use.

There is scope for future work in calibrating the parameters of the MAPS tool, such as the number of clusters that the K-Means algorithm segments images into, as well as the maximum emission angle that is allowed for an input image. The latter was shown in testing to lead to the same features exhibiting significantly different morphologies, despite similar lighting conditions. This may be possible by testing the tool upon artificially created elevation data and images of pits. Other improvements are foreseen by considering the geomorphology of the surrounding Martian surface as a means of calibrating the distribution of the non-shadow pixel values and of controlling their false discovery rates.

How to cite: Le Corre, D., Mason, N., Bernard-Salas, J., Mary, D., and Cox, N.: Martian Pit Shadow Extractor (MAPS): Determining the Apparent Depths of Martian Pits from the Morphology of their Shadows, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-186, https://doi.org/10.5194/icg2022-186, 2022.

18:25–18:40
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ICG2022-339
Susan Conway, Frances Butcher, Anna Grau Galofre, and Axel Noblet

Mars is thought to have been a hyperarid desert for at least the last one billion years of its history and so water is locked up in the two polar ice caps, ground ice and an extensive band of debris covered glaciers found in the mid-latitudes. Layers expressed by the polar caps are thought to record the most recent climate cycles of Mars – up to a few tens of Ma. The debris covered glaciers are thought to date to hundreds of millions of years in age and potentially record a deeper climate record. Here, we report on the widespread occurrence of layered outcrops intimately associated with glaciated terrains in Deuteronilus Mensae and the Eastern Hellas region – two areas renowned for their extremely extensive and well-preserved debris covered glaciers. We explore the relationship between these layered outcrops and the debris covered glaciers by exploiting images and elevation data from the High Resolution Science Imaging Experiment (HiRISE) at 25 cm/pixel, Context camera (CTX) at 6 m/pixel and Colour and Stereo Imaging System (CaSSIS) at 4.5 m/pixel. Because these outcrops have similar morphology in both the northern and the southern hemisphere they point to a globally relevant process. Our aim is to test the hypothesis that these deposits represent remnant glacial deposits, which could give information of Mars climate beyond that obtainable by studying the polar caps.

How to cite: Conway, S., Butcher, F., Grau Galofre, A., and Noblet, A.: The morphology of glacier-associated layered deposits on Mars, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-339, https://doi.org/10.5194/icg2022-339, 2022.

18:40–18:55
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ICG2022-282
Meven Philippe, Susan J. Conway, Richard J. Soare, and Lauren E. McKeown

On Earth, sharp drops in negative temperatures can cause ice-cemented ground to crack and form polygonal patterns. Over time, water and/or sand can infill cracks (Péwé, 1959; Lachenbruch, 1962; Black, 1976). This material can freeze into ice or sand wedges, uplifting polygon margins and forming low-centred polygons (LCPs). When wedges degrade, elevation of margins decreases which forms high-centred polygons (HCPs). On Mars, similar polygonally-patterned ground is observed (with LCPs and HCPs) and also thought to be formed by thermal contraction of the ground (Mellon, 1997), but the type of wedge is unknown. Liquid water is thought to have been unstable on Mars’s surface for 3 billion years, but a recent study in Utopia Planitia suggested an ice-wedge origin for the studied polygons (Soare et al., 2021). This implies near-surface liquid water on Mars in the recent past, and presence of massive ice in the subsurface – an interesting source of water for future manned missions.

Here, we investigate the relationship between polygon density & type and the properties of the substrate that bears them (e.g. grain size or porosity). We focus on polygons in Utopia Planitia and use the same grid-based mapping technique as Soare et al. (2021). This technique consists in gridding the study area in squares of given dimensions (500 x 500 m), and in each square noting the presence of each polygon type. We mapped three geomorphological units in our study area: the “sinuous unit” (sinuous shape, polygon-rich), the “boulder unit” (covered in decametric boulders, polygon-poor), and the craters.  For each unit we calculated parameters (e.g. percentage of squares containing polygons) which we expect to act as proxies for different substrate properties (e.g. capacity for the ground to form polygonally-patterned ground). We found that:

  • the boulder unit is an ice-poor massive material hindering ground cracking / polygon formation;
  • the sinuous unit is an ice-rich material favouring ground cracking, but not ice wedge formation or preservation;
  • crater floors host ice-rich material favouring ground cracking, and are environments favourable to ice wedge formation and preservation.

Our study area is located at the terminus of Hrad Vallis, a valley system originating from a nearby volcano (Elysium Mons) and thought to have conveyed both lava and mudflows (Hamilton et al., 2018). Therefore, we suggest that the boulder unit could be a low-viscosity lava flow, which would have been topped by a later viscous mudflow that formed the sinuous unit, both originating from Hrad Vallis. The low elevation of crater floors compared to their surroundings leads to higher atmospheric pressure and lower temperatures at their bottom. This could favour ground ice formation and preservation – a “cold trap effect” already discussed by Conway et al. (2018) and Soare et al. (2021).

In summary, we show that polygon density and type can provide insights into the geological properties of a substrate, and here it allowed us to suggest origins for the units of our study zone that are consistent with the geological context of the area.

How to cite: Philippe, M., J. Conway, S., J. Soare, R., and E. McKeown, L.: Relationship between thermal-contraction polygons and substrate properties on Mars, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-282, https://doi.org/10.5194/icg2022-282, 2022.

18:55–19:00