GM11.1

GM11 EDI
Planetary Geomorphology 

The Planetary Geomorphology session aims to bring together geomorphologists who study the Earth with those who work on other bodies such as Mars, Venus, Mercury, the Moon, icy satellites of the outer solar system, comets, and/or asteroids. Studies applicable to landscapes on any scale on any solid body are welcome. We particularly encourage those who use Earth analogues or laboratory/numerical simulation to submit their work. Considered processes could include aeolian, volcanic, tectonic, fluvial, glacial, periglacial, or "undetermined" ones. We especially welcome contributions from early-career scientists and geomorphologists who are new to planetary science.

Co-organized by PS11, co-sponsored by IAG
Convener: Susan Conway | Co-conveners: Frances E. G. ButcherECSECS, Nikolaus J. Kuhn, Stephen BroughECSECS, Tjalling de Haas
Presentations
| Thu, 26 May, 15:10–18:30 (CEST)
 
Room 0.16

Presentations: Thu, 26 May | Room 0.16

Chairperson: Susan Conway
15:10–15:12
15:12–15:19
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EGU22-11526
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ECS
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Virtual presentation
Riccardo Pozzobon, Costanza Rossi, Alice Lucchetti, Matteo Massironi, Maurizio Pajola, Luca Penasa, and Giovanni Munaretto

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.

How to cite: Pozzobon, R., Rossi, C., Lucchetti, A., Massironi, M., Pajola, M., Penasa, L., and Munaretto, G.: 3D geologic model of Uruk Sulcus region on Ganymede, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11526, https://doi.org/10.5194/egusphere-egu22-11526, 2022.

15:19–15:23
15:23–15:30
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EGU22-7737
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ECS
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On-site presentation
John Walding and Adriana Paluszny

The smallest of Jupiter’s Galilean satellites, Europa has one of the smoothest surfaces of our solar system. This is due to the comparative youth of its ice crust which is believed to resurface over time. This ice crust is observed to be crisscrossed with a multitude of linae, thought to be large-scale fractures, as well as dotted with numerous regions of lenticulae and chaos. Tidal stresses on Europa are modelled according to Wahr (2009) and are evaluated over periods of 1e3-1e6 years. The nucleation, growth and interaction of fractures is modelled using a three-dimensional finite element-based fracture simulator which assumes that the material is linear, isotropic and homogeneous. Other material properties are drawn from Selvans (2009). Nucleation of fractures is assumed to occur only in tension, and sub-scale nucleation modelled by a damage criterion models the weakening of the ice matrix. Stress intensity factors at the fracture tips are computed with the displacement correlation method. Fracture growth is modelled geometrically as a function of the accumulation of stresses on the fracture tips. The simulator evaluates how tidal stresses are expected to induce the nucleation and growth of fractures on the surface of Europa. Nucleation and growth are modelled in two regions, an equatorial region and a sub-polar region, representative of deformation scenarios on the satellite surface. The simulation runs at two different scales. Tidal forces are computed at the satellite scale using Wahr (2009). These are applied as boundary conditions of smaller scale 100km x 100km x 20km cuboidal regions, in which the nucleation and growth of fractures is modelled. Within each region, a number of three dimensional non-planar fractures grow and interact. Resulting patterns are compared against observational data.

How to cite: Walding, J. and Paluszny, A.: Multi-scale modelling of ice fracture patterns on the surface of Europa using computationally derived tidal boundary conditions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7737, https://doi.org/10.5194/egusphere-egu22-7737, 2022.

15:30–15:34
15:34–15:41
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EGU22-10095
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ECS
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Highlight
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Presentation form not yet defined
Costanza Rossi, Alice Lucchetti, Matteo Massironi, Riccardo Pozzobon, Luca Penasa, Giovanni Munaretto, and Maurizio Pajola

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.

How to cite: Rossi, C., Lucchetti, A., Massironi, M., Pozzobon, R., Penasa, L., Munaretto, G., and Pajola, M.: Tectonic phases in Galileo Regio, Ganymede’s dark terrain., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10095, https://doi.org/10.5194/egusphere-egu22-10095, 2022.

15:41–15:45
15:45–15:52
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EGU22-2099
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ECS
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Virtual presentation
Shania James, Saranya R Chandran, and Sajin Kumar Kochappi Sathyan

Terrestrial impact craters,having dynamically modified the Earth's surface, depict characteristic radial, centripetal and concentric drainage patterns, by virtue of its morphology. These typical drainage patterns, developed in relatively pristine conditions, often during or immediately after its formation, are modified owing to progressive fluvial action. Crater denudation are influenced by climate, target lithology, morphology, and time.  Here, in the study, the crater denudation, designated as a function of fluvial activity by introducing a parameter titled ‘Denudation Index’ (DI), showcase how drainages modify the morphology of an impetus structure by quantifying the ratio of total first order radial/centripetal streams originating from the crater rim and central elevated area to the total first order streams. DI was calculated for 71 terrestrial craters, by keeping aside the buried, morphologically unexpressed, water filled, and data sparse craters. The DI, which is a measure of rim degradation caused by fluvial activity, is expressed on a scale of 0-1, as

               RI =  [(Aout/Tout)+(Ain/Tin)]/2                              (1)

               DI = 1–RI                                                               (2)

where, RI is Retention Index,  Aout is number of 1st order streams flowing outward (i.e., radial) from rim, Tout is total number of 1st order streams flowing radially from rim, Ain is number of 1st order streams flowing inward (i.e., centripetally) from rim, and Tin is total number of 1st order streams flowing centripetally from rim.

The DI of craters was correlated with relative morphology, age, lithology and paleoclimate. Paleoclimatic data was generated by reconstructing crater paleo-positions at 1 Ma interval through GPlates and deciphering the paleoclimate a crater experienced at a specific time utilizing Scotese Global Climate Model [1].

The study provides a series of relevant observations. The DI of craters impacting to crystalline target (such as DIDecaturville= 0.55) is higher than ones on sedimentary target (DIRochechouart= 0.87). The observation can be attributed to the brittle nature of crystalline rocks aiding more advanced fracture formation and thereby, more extensive and sophisticated drainage network development. The DI of younger craters (DIHickman=0.67) (0.02–0.10 Ma) can be higher than older craters (DITabun-Khara-Obo=0.64) (150±20Ma). The study also revealed that, in general, complex craters shows higher DI values, owing to older formation ages than simple craters.  The study also showed that craters in equatorial rainy climate are more denuded than craters in other climates. The above observations suggest that the cumulative effects of target lithology, climate and morphological traits strongly influence crater denudation. Thus, the study provides a new parameter (DI) and method for determining terrestrial impact crater denudation by depicting that drainage network of a crater, as we see today, is unique in itself, entailing significant influences of target lithology, crater age, crater morphology and paleoclimates.

Reference: Scotese, C.R., 2016. Global Climate Change Animation (540Ma to Modern), https://youtu.be/DGf5pZMkjA0.

How to cite: James, S., R Chandran, S., and Kochappi Sathyan, S. K.: Quantifying the morphological degradation of terrestrial impact craters through a Denudation Index derived using drainage network signatures, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2099, https://doi.org/10.5194/egusphere-egu22-2099, 2022.

15:52–15:56
15:56–16:03
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EGU22-1915
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ECS
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On-site presentation
Elettra Mariani and Pascal Allemand

Methane has been detected these last years in the Martian atmosphere both from orbit (TGO-ExoMars mission - still active) and from ground (Curiosity rover – Mars Science laboratory mission). The sources of methane remain undetected. As the life time of methane in the Martian atmosphere should be less than few months, these sources are currently active at the Martian surface. The localization and the geometry of these sources remain an open question. Emission centers could be localized in peculiar zones on which it is possible to detect methane. Methane could also be emitted in wide areas and be locally concentrated by atmospheric processes. The aim of this study is to compare the geology and geomorphology three impact craters (Gale, Gusev and Vernal) in which methane has been detected from orbit and/or from ground. Satellite and in situ hyperspectral data (for Gusev, hyperspectral data from Spirit - for Gale, data from Curiosity), as well as high-resolution Context Camera (CTX) and HiRISE images (MRO mission) were also considered. Digital Elevation Models (DEM) were calculated from the highest resolution images that are available. Geomorphological maps were drawn for each crater through GIS projects. For each crater, the possible areas of emission are defined from criteria defined on terrestrial analogs located in Chile and Antarctica. Differences and similarities between the three selected craters are discussed.

How to cite: Mariani, E. and Allemand, P.: Possible geomorphic indicators of methane emission in three Martian impact craters, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1915, https://doi.org/10.5194/egusphere-egu22-1915, 2022.

16:03–16:07
16:07–16:14
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EGU22-507
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ECS
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Virtual presentation
Saranya R. Chandran, Shania James, Devika Padmakumar, Varsha M. Nair, and Sajinkumar Kochappi Sathyan

The surface of the earth is continuously modified by the action of various active geological agents, and one of the resultant is erosion. Climate, lithology, slope, precipitation, temperature, vegetation and anthropogenic activities are the chief controlling factors of erosional processes. The rate of erosion associated with various geomorphological features has been estimated using several different methods. Meteorite impact craters being a positive relief feature, formed by an impetuous process, thus, is an ideal candidate for quantifying the rate of erosion. Several authors have attempted to quantify the erosion rate with the availability of scanty number of terrestrial impact craters. In this study, apart from taking into account other factors, paleoclimatic parameters have been incorporated to estimate the erosion rate of simple impact craters. The rate of erosion has been quantified in selected terrestrial simple impact craters considering the influence of various climatic zones traversed by the crater in relation to its topographical parameters and the geological province where the crater is located. The temporal range of each crater in distinct paleoclimatic zoneshave been derived to better constrain the influence of climate on erosion. The rate of erosion of the region hosting the impact craters and the individual crater are estimated separately using different methods. In the first method, the relief of the geological province where the crater is located is considered and in the second method, the initial relief of the transient impact crater is calculated using a set of crater morphological parameters. The estimated values of erosion rates of craters are correlated with the published works. The values are found to be similar except for the older craters, which we believe due to the large uncertainties associated with paleoclimatic data. Difference in the erosion rates of older craters can also be attributed to dynamic evolutionary trends of terrestrial simple impact craters pertaining to the influence of various regional elements in the vicinity of the crater including the drainage, tectonic activities, precipitation, temperature and lithology.

How to cite: R. Chandran, S., James, S., Padmakumar, D., M. Nair, V., and Kochappi Sathyan, S.: Quantifying the rate of erosion of simple terrestrial meteorite impact craters, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-507, https://doi.org/10.5194/egusphere-egu22-507, 2022.

16:14–16:18
16:18–16:25
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EGU22-8488
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ECS
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Virtual presentation
András Szilágyi-Sándor and Balázs Székely

The area on the eastern slopes of Tharsis (Thaumasia), northern from Argyre and southern from Margaritifer is dominated by the Uzboi Vallis and Nirgal Vallis. Their (at least partial) fluvial origin is accepted since the Mariner-Viking era. Uzboi Vallis thought to be part of the ancient Uzboi–Ladon–Morava River System (ULM). ULM is thought to be created while it served as the overflow channel of the southern Argyre crater. Nirgal Vallis is the largest tributary of Uzboi. Its source region is in the direction of the Thaumasia Mountains.

The area experienced numerous effects during its history. In this study our goal was to separate these effects in a chronological order as far as it is possible. Therefore comprehensive investigations (using MOLA and THEMIS) were carried out and a detailed analysis of these two valleys was made using HiRISE images and HiRISE-derived digital elevation models. HiRISE DEMs allow the surfaces to be studied and evaluated with a resolution of better than one meter.

Several geomorphometric methods were applied for the area: swath analysis, the distribution of the tributary valleys, sinuosity calculation, and runoff modeling. The vallis was divided into sections based on its main features. Section A, unlike other sections, is characterized by dendritic tributary system. Tributaries are found both on left and right sides. Section B is a kind of transitional zone, the tributaries are getting rare. Section C was defined as a sinuous segment. Tributaries here are very rare.  Section D is deeply incised, the thalweg is broken at several points and has a subhorizontal trend. According to the extremely low number of tributaries and the modifying effect of the neighboring impact craters the water divides are fuzzy. The path of this section is also sinuous. Section E is the deepest part of the whole Nirgal Vallis this is an unusual condition, because in the case of the terrestrial rivers the deepest part is regularly at the end of the confluence. Section F has to be separated from Section E because it shows influence of several effects. Section F has got only one (SW-NE) tributary which is significant in length and dominates the morphology of the area south from the Nirgal‒Uzboi confluence.

In our interpretation the sections detailed above seem to be at least partially related to wrinkle ridges noticeable from Thaumasia Mountains to Uzboi Vallis and are similar to those on Solis Planum. The effect of the wrinkle ridges is controlling the morphology of the plateau, and may be in connection with the tributaries.

Further geomorphological investigation may lead to the separation of the different effects formed Nirgal throughout its history.

How to cite: Szilágyi-Sándor, A. and Székely, B.: Geomorphometric Analysis of the Martian Uzboi-Nirgal Region, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8488, https://doi.org/10.5194/egusphere-egu22-8488, 2022.

16:25–16:29
16:29–16:36
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EGU22-7147
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ECS
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Presentation form not yet defined
Eric Deal

Forming spontaneously when sediment laden water flows across an erodible material, terrestrial river channels possess a distinct shape, with robust relationships between channel width, depth and flow velocity that hold true over a million-fold change in water flux and for widths spanning less than a meter to more than a kilometer. These patterns have long since been described, however, a process-based understanding of what determines channel shape and scale is just beginning to emerge. This recent work has made clear the key elements to understanding terrestrial river channels which include: lateral momentum exchange within the flow, the frictional behavior of the channel boundary on the flow, and the dynamics of bedload sediment transport in the channel.  Bringing together these elements, a theoretical prediction for steady-state channel shape is derived directly from the Navier-Stokes equations of motion. 

The key result is an analytical description of channel geometry relating seven variables: flow width, depth, velocity, channel slope, and characteristic grain size, water flux and sediment flux. Using these equations, any four variables can be predicted if the other three are known. The theory was tested against 2500 terrestrial river reaches including both bedrock and alluvial rivers, where width varies by three orders of magnitude, and characteristic water flux varies by seven orders of magnitude. Using characteristic water flux, characteristic grain size, and a global average sediment transport rate, flow width, depth and velocity are predicted to within a factor of two for >80% of reaches.  

There are other long-lived geophysical and extraterrestrial flows over erodible materials that can be addressed with a general understanding of self-formed channels. With estimates of how fluid drag, turbulence generation and sediment transport might change on other planetary bodies, this model could be applied to extraterrestrial river networks such as those observed on Mars or Titan. More fundamentally, this work suggests a general approach to understand self-formed channels in an erodible medium generated by different kinds of flow, such as valley glaciers and subglacial river channels on both Earth and Mars. 

How to cite: Deal, E.: A mechanistic understanding of self-formed channel shape and scale, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7147, https://doi.org/10.5194/egusphere-egu22-7147, 2022.

16:36–16:40
Coffee break
Chairperson: Susan Conway
17:00–17:01
17:01–17:08
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EGU22-10768
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ECS
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Highlight
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Virtual presentation
Luke Gezovich, Piret Plink-Bjorklund, and Jack Henry

Fluvial fans and river deltas are both fan-shaped landforms that contain complex channel networks. A critical difference between these landforms is that deltas form only along a standing body of water, whereas fluvial fans may form hundreds of kilometers from oceans or lakes. Accurately distinguishing between deltas and fluvial fans is thus critical for identifying paleo-shorelines on planetary bodies. Here we test an ensemble of quantitative methods to differentiate fluvial fans and deltas on Earth, and apply the methodology to Mars. We quantify differences in channel divergence angles, and in downstream changes of channel reach lengths and channel width between the divergence nodes. These differences in channel networks occur because fluvial fans build by channel avulsions, whereas delta build by avulsions as well as mouth bar growth and consequent bifurcations. Bifurcations in deltas form channel divergence angles of approximately 77° and cause a distinct downstream decrease in channel reach length and in channel width at bifurcation nodes. In contrast, avulsions in fluvial fans form considerably smaller channel divergence angles. Down-fan channel narrowing is also not linked to divergence nodes. This initial dataset shows that the methodology is applicable both on Earth and Mars, and that the Jezero system is likely a fluvial fan rather than a delta. These results indicate that channel networks need to be carefully assessed if used for the estimation of the location of paleo-shorelines on planetary bodies, as only deltas systematically occur at shorelines. Alternatively, additional evidence is needed for the presence of shorelines as fluvial fans may also occur at shorelines. On Earth, fluvial fans are less sensitive to sea-level rise and coastal hazards than deltas, due to upstream morphodynamic controls.

How to cite: Gezovich, L., Plink-Bjorklund, P., and Henry, J.: Morphometric analysis of channel networks suggests the Jezero system is a fluvial fan rather than a delta, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10768, https://doi.org/10.5194/egusphere-egu22-10768, 2022.

17:08–17:12
17:12–17:19
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EGU22-1282
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ECS
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Presentation form not yet defined
Rickbir Bahia and Vilmos Steinmann

Introduction:  Mars’ surface is carved by an array of dendritic valley networks, which are evidence for ancient water cycles and surface run-off on Mars. The majority of these networks appear to have formed during the Late Noachian – Early Hesperian (3.8 to 3.6 Ga) and resemble terrestrial precipitation-fed systems. After this period, other than localised valleys present on the flanks of several volcanoes, valley network formation appears to have rapidly decreased, indicating that Mars’ climate experienced a sudden change from a warm and wet state to hyper aridity. However, a recent analysis of Amazonian – Hesperian aged flat crater-bottom deposits and alluvial fans indicates that localised areas of wettest persisted after the Early Hesperian. By analysing the morphological, morphometric, and paleohydraulic characteristics, and formation timescales of valley networks of different ages, one can gain a better understanding of the evolution of Mars’ aridity.

In this study, we aim to perform a detailed analysis of valley networks of differing ages to determine their formation origin and the duration of aqueous activity required to incise their troughs. At present we have performed formation timescale analysis on an Amazonian-Hesperian aged valley network – the results are presented below.

Data and Methods: A combination of GIS software packages were used to perform the analysis: SAGA GIS was used to determine full water depth estimates and flow width via the multiply flow direction method; GRASS GIS was used to determine flow accumulation, flow direction, and upstream slope; ArcGIS Pro was used to perform spatially variable drainage area calculations for Hack’s Law and Flint’s Law calculations. Valley networks were initially identified using the Hynek et al. (2010) valley map, and narrowed to different surface ages based on the Tanaka et al. (2014) surface age map. Detailed mapping and morphological analyses of these valleys was performed using Context Camera images (5 m per pixel). High-Resolution Stereo Camera (HRSC) DEMs were used for paleohydraulic and formation timescale analysis. For the formation timescale calculation, the estimated volume (km3) of each pixel was divided by the volumetric transport rate (km3/yr).

Initial Results: At present, we have applied the technique to a valley network located north-east of Lowell Crater (49.82 °S 77.16 °W). The source is within a Middle Noachian highland unit, with the majority of the network incising an Amazonian-Hesperian aged impact unit. The valley network has a main valley length of ~123 km, an almost linear profile, and an average slope (dz/dl) of ~ 0.012. Based on a calculated average water velocity of 6.8 m/s and an average 12.25 m water depth, the average formation time for the whole study area is 23235.3 yr (1 sigma standard deviation = 39401.2 yr).

Discussion: It is apparent the examined young valley is immature compared to previously examined Late Noachian – Early Hesperian Martian valley networks, which have minimum formation timescales ranging from 105 to 107 years. Applying formation timescale and paleohydraulic calculations to valley networks from a range of ages, we will be able to better understand the evolution of fluvial activity that formed them.

How to cite: Bahia, R. and Steinmann, V.: The Evolution of Martian Valley Network Formation Timescales, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1282, https://doi.org/10.5194/egusphere-egu22-1282, 2022.

17:19–17:23
17:23–17:30
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EGU22-4749
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ECS
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Presentation form not yet defined
Anna Grau Galofre, Kelin Whipple, and Philip Christensen

The lack of evidence for large-scale glacial erosion on Mars has led to the belief that any ice sheet that may have existed had to be frozen to the ground. We challenge this argument, suggesting instead that the fingerprints of Martian warm-based ice masses should be the remnants of their drainage systems, including channel networks and eskers, instead of the large scoured fields generally associated with terrestrial Quaternary glaciation. Our results use the terrestrial glacial hydrology framework to interrogate how the Martian lower surface gravity should affect the state and evolution of the glacial drainage system, ice sliding velocity, and the rates of glacial erosion. Taking as reference the scale and characteristics of the ancient southern circumpolar ice sheet that deposited the Dorsa Argentea formation, we compare the theoretical behavior of geometrically identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and producing characteristically scoured glacial landscapes, on Mars the lower gravity favors the formation of efficient subglacial channelized drainage. The apparent lack of large-scale glacial fingerprints on Mars, such as scouring marks, drumlins, lineations, etc., is thus to be expected. 

How to cite: Grau Galofre, A., Whipple, K., and Christensen, P.: The (missing) erosional record of warm-based glaciation on early Mars, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4749, https://doi.org/10.5194/egusphere-egu22-4749, 2022.

17:30–17:34
17:34–17:41
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EGU22-6131
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Virtual presentation
Federica Trudu, Alberto Vancheri, and Nikolaus J. Kuhn

The fluid dynamics of different sedimentological processes are often studied and interpreted by using models based on a combination of Newton dynamics and an empirical expression of the drag force in function of the drag coefficient. However, neither the expression of the drag force nor the value of the drag have a unique expression, depending on the state of the fluid (laminar, transitional, and turbulent) and on the shape and dimensions of the sediments. These (semi-) empirical models are often inaccurate, in particular in planetary sciences when gravity plays a determining role, like, for example, when calculating the terminal settling velocity of natural sediments on Mars. In this work, a numerical simulation code based on the Lattice Boltzmann Method (LBM) is used to study how settling velocity of some reference spherical particles changes at different gravity conditions, ranging from hyper to reduced gravity. LBM is a discrete computational method based on the kinetic Boltzmann equation that describes the dynamics of a fluid on a mesoscopic scale. This study shows that, despite the LB model has been calibrated and validated using only the set of experimental data collected during a parabolic flight, its validity goes beyond, being able to predict the correct terminal velocity of different particles, with different density and diameters. In addition, the same settings can be used to simulate other important processes that occur when sediments interact with each other and the fluid phase, such as hindered settling and the drafting, kissing, and tumbling phenomenon. This makes the Lattice Boltzmann method an ideal candidate for studying a wide range of sedimentological processes where a mesoscale accurate description is crucial to understand macroscale phenomena.

How to cite: Trudu, F., Vancheri, A., and Kuhn, N. J.: The Lattice Boltzmann Method: one single tool to address different sedimentation processes, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6131, https://doi.org/10.5194/egusphere-egu22-6131, 2022.

17:41–17:45
17:45–17:52
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EGU22-3969
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ECS
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Highlight
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On-site presentation
Vojtěch Cuřín, Petr Brož, Ernst Hauber, and Yannis Markonis

Landforms with specific flow-like morphology are characteristic for the area of Adamas Labyrinthus in the southwestern part of Utopia Planitia. These landforms have been previously described as degraded mud flows originating from a partly frozen muddy ocean. However, such interpretation remained ambiguous as lava flows observed elsewhere on Mars look quite similar. We mapped and investigated over 300 features spread across a 500 × 1300 km large area in order to reveal whether they were formed by the movement of mud or lava. Based on our systematic examination of their shapes, their spatial distribution as well as geological context we conclude that they were formed due to the ejection of mud from a gradually freezing muddy body. Once exposed to the surface, the mud spread by flowing over the surface, while freezing at the same time. This limited its ability to flow and caused the resulting outflows to have an appearance similar to terrestrial lava flows. Emergent landforms differentiated based on the effusion rates and overall volumes of the source material and subsequently degraded over time as the liquid part of the compound sublimed away. These processes eventually lead to the characteristic morphology of hills, ridges, plateaus, and complexly layered units which we observe today. We propose that all the >300 studied features were formed by subsurface sediment mobilization and that the material likely originated from the same source.

How to cite: Cuřín, V., Brož, P., Hauber, E., and Markonis, Y.: Products of Sedimentary Volcanism around Adamas Labyrinthus, Mars, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3969, https://doi.org/10.5194/egusphere-egu22-3969, 2022.

17:52–17:56
17:56–18:03
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EGU22-10037
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ECS
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On-site presentation
Anna Maria Gargiulo, Maria Marsella, Mauro Coltelli, and Antonio Genova

Volcanic and tectonic features significantly differ depending on the eruption styles and on the tectonic processes from which they were originated.

We present here a study focused on the identification and characterization of Earth volcanic and tectonic structures by analyzing a combination of airborne and satellite optical images and Synthetic Aperture Radar (SAR) data. Our work is aimed at developing a robust approach to compare Earth and other terrestrial planet’s surface features, and to constrain their nature and occurrence in relation to volcano-tectonic activity.

We focus on the Mt. Etna and the Aeolian Islands, which host several active volcanoes (e.g., Stromboli and Vulcano) and represent one of the most tectonically and magmatically active zones in the Mediterranean Sea area. Indeed, Etna, Vulcano and Stromboli, despite their geographical proximity, provide examples of very different volcanic activities and thus of diverse complex morphologies.

The first stage of this study includes the processing of Pleiades tri-stereo acquisitions and high resolution DEMs of the regions of interest. This dataset will be analyzed through a novel automatic feature extraction algorithm that identifies the most common structures originating from natural processes, i.e., volcano-tectonic activities, and strong erosions.

Pyroclastic cones, lava flows and fissures are some of the signs that we can detect and compare with accurate volcano-tectonic maps and geological maps. This further step will allow resolving their nature and origins, distinguishing features based on geometric criteria and according to the volcanic and tectonic processes that generated them.

Moreover, the processing of COSMO-SkyMed (CSK) and Sentinel intensity data will be carried out to determine if the most relevant  extracted features match those visible on high-resolution Digital Elevation Models from Airborne photogrammetry and Lidar Surveying. This analysis is also devoted to understand how SAR observation capabilities vary with sensor resolution, geometric distortion and surface roughness.

How to cite: Gargiulo, A. M., Marsella, M., Coltelli, M., and Genova, A.: An approach for volcano-tectonic features extraction using optical and radar remote sensing data, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10037, https://doi.org/10.5194/egusphere-egu22-10037, 2022.

18:03–18:07
18:07–18:14
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EGU22-9315
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ECS
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On-site presentation
Richard Love, Derek Jackson, Timothy Michaels, Thomas Smyth, Jean-Philippe Avouac, and Andrew Cooper

Until recently, sand dunes on Mars were thought to be relict landforms from paleo-atmospheric conditions. However, recent evidence from high resolution imagery of Mars’ surface have shown that aeolian processes are a dominant, contemporary force, driving geomorphological change in dune fields across the planet. Images from the HiRISE camera have demonstrated that not only are dune fields active on Mars, but they are undergoing change comparable to some terrestrial rates.

In the absence of localised in situ wind data returned by successive lander missions, the atmospheric-surface interactions contributing to aeolian change across the surface of Mars have largely relied on mesoscale modelling, these large-scale models have not fully resolved the processes occurring at local landform scales. In order to attempt to resolve the interactions driving the modification of dune fields, microscale wind flow modelling (<2 m grid spacing) is required over a site which has been shown to undergo change over the history of HiRISE imagery.

A large barchan dune field in the Nili Patera caldera was selected for examination, as this site undergoes significant aeolian change. This site has a robust HiRISE image collection, but no in situ data, and is therefore an ideal location to test a new multiscale airflow modelling approach. This study proposes combining macro- (>100 km), meso- (>2 km) and microscale (>2 m) modelling of the Martian atmosphere.

The resolution of a Global Climate Model (GCM) is too coarse to resolve the near-surface processes themselves, but their output can be used to provide an initial state and boundary conditions for mesoscale modelling. However, the maximum resolution of a typical mesoscale model is still too coarse to resolve the microscale dynamics contributing to aeolian change at dune fields on Mars. To examine the fine-scale interactions occurring over the surface of dune fields, microscale Computational Fluid Dynamics (CFD) simulations utilising the mesoscale model output are required.

The surface shear stress output from the CFD simulations and corresponding flux predictions were directly compared to HiRISE observations of Nili Patera, using COSI-Corr software to verify the microscale modelling results. We find that this multi-scale modelling approach provides promising initial comparisons between CFD simulations and HiRISE observations, both in the directionality of dune change and the rates of sediment flux, and different Mars seasons., however these observations are influenced by the seasonal variability on Mars, altering approach directions and wind speeds to produce heterogeneous patterns of aeolian flux.

How to cite: Love, R., Jackson, D., Michaels, T., Smyth, T., Avouac, J.-P., and Cooper, A.: Measured and predicted aeolian flux at Nili Patera, Mars: Computational Fluid Dynamics-derived transport modelling and Cosi-CORR rates, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9315, https://doi.org/10.5194/egusphere-egu22-9315, 2022.

18:14–18:18
18:18–18:25
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EGU22-11400
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Virtual presentation
Luca Penasa, Alice Lucchetti, Riccardo Pozzobon, Giovanni Munaretto, Maurizio Pajola, and Costanza Rossi

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.

How to cite: Penasa, L., Lucchetti, A., Pozzobon, R., Munaretto, G., Pajola, M., and Rossi, C.: A Discrete Elements Modelling Framework for the Parametric Study of Landslides in Low Gravity Environments, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11400, https://doi.org/10.5194/egusphere-egu22-11400, 2022.

18:25–18:29
18:29–18:30