Orals: Tue, 29 Apr | Room 1.34
The formation of Tharsis affected nearly the entire western hemisphere of Mars and had a profound effect on Martian geodynamics. Tharsis-related lithospheric deformation created a variety of tectonic structures that record past stress fields, some of which may still be active today. However, evidence for very recent endogenic activity (<1 Ma) in Tharsis remains limited even after the seismic measurements by the NASA InSight mission. Very few morphologically pristine tectonic structures have been discovered in remote sensing data, limiting our understanding of the current endogenic activity in Tharsis.
Building on our previous research in the southeastern Tharsis region, we focus on the Claritas Fossae region. This area displays several cross-cutting fracture and fault sets, recording a complex history of multiple volcano-tectonic events. Using High Resolution Imaging Science Experiment (HiRISE) images and stereo image-derived Digital Elevation Models (DEMs), we identified uphill-facing scarps on the west-facing Claritas Rupes scarp, which bounds a major N-S-trending extensional structure, informally called the Thaumasia Graben. The two-kilometer-high steep slopes of Claritas Rupes experience intense mass wasting, producing rockfalls (boulders) that accumulate against these uphill-facing scarps. Despite the high boulder fall rates, which over time could fill the accommodation space created by the uphill-facing scarps and mask them, small of these scarps retain a pristine topography. These observations suggest a very young age (<1 Ma) for these scarps. We interpret these scarps as surface expressions of normal faulting linked to Deep-seated Gravitational Slope Deformations (DGSDs), likely caused by seismic activity tied to reactivation of the Claritas Rupes fault associated with Thaumasia Graben subsidence. This indicates neotectonic activity in the region, which is potentially still ongoing.
To better constrain the tectonic processes and the mechanism of the very recent small-scale faulting at the Claritas Rupes scarp, our current structural mapping aims at deciphering the orientations and the spatiotemporal relationships of these scarps. Our approach involves obtaining dip angles through a planar fitting method and quantifying shortening along mapped scarp features. This forms the basis for determining effective stress distribution under isotropic stress conditions with plane strain assumptions, offering insights into the youngest stages of the tectonic evolution of this region. Our satellite image-based morphological investigations focusing on fresh-looking scarps show great advances in tectonic feature mapping, offering valuable insights into inaccessible subsurface endogenic processes in southeastern Tharsis.
How to cite: Pieterek, B., Brož, P., Hauber, E., and Karagoz, O.: Evidence for very recent tectonic activity in southern Tharsis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-518, https://doi.org/10.5194/egusphere-egu25-518, 2025.
During the ESA funded 4D Dynamic Earth project, different sensitivity studies are performed to understand the applicability of current ground and satellite datasets available to study the dynamical behavior of the solid Earth, in particular the complete mantle. This project is a joint effort between ESA and many European universities and is lead by Delft University of Technology (https://4ddynamicearth.tudelft.nl/).
The project consists of ten work packages, many of them relying on some form of forward geodynamical modelling. Given the diversity of participants multiple codes are used in the project: a 2D axisymmetric Python code developed by C.T. at the Utrecht University, a 3D Matlab code developed by O.O-G. and the 3D massively parallel C++ community code ASPECT.
One recurring quantity that is of paramount importance for some work packages is dynamic topography, i.e. the outer surface expression to dynamic mantle flow. We have therefore designed a simple isothermal experiment of an anomalous sphere present in the mantle of a planet (the core is ignored as is customary in whole-Earth geodynamic modelling). The sphere itself can be positively or negatively buoyant, and the mantle can be isoviscous or characterized by a radial viscosity profile. Boundary conditions at the core-mantle boundary and at the surface are either no-slip or free-slip.
Dynamic topography calculations involve the radial stress which is derived from the primitive variables velocity (actually, its gradient) and pressure which are found to be sensitive to mesh size in both radial and lateral directions. We therefore report on the root mean square velocity, the surface strain rate, stress and dynamic topography and the gravity anomaly for a range of experiments. Our objective is two-fold: characterize the accuracy of our codes and provide the community with a benchmark.
All three codes are Finite Element codes and all rely on the Taylor-Hood element but they are also quite different with respect to meshing and solver architecture. Nevertheless we find that all measured quantities converge within approx. 1% for radial resolutions of at least 30km.
How to cite: Thieulot, C., Ortega-Gelabert, O., Root, B., and Conrad, C.: Benchmarking dynamic topography across geodynamical codes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8998, https://doi.org/10.5194/egusphere-egu25-8998, 2025.
Observations of several short-period rocky exoplanets (e.g., LHS 3844 b, TRAPPIST-1 b, GJ 367 b) suggest that they do no host substantial secondary atmospheres, which makes their surfaces directly accessible to spectral characterisation. Various minerals and rock types have potentially distinguishable surface reflectance spectra, allowing for observational characterisation of surface geology for such atmosphere-less exoplanets. While extensive surface spectra for Solar System lithologies are available, they may not capture the full range of surface diversity, as rocky exoplanets display a bulk compositional diversity far exceeding that seen in the Solar System. To address this gap, we explore potential surface mineralogies of volatile-free rocky exoplanets, with compositional diversity informed by stellar abundances.
We model magma compositions formed from bulk mantle melting in the NCFMASCr system with a Gibbs free energy minimization algorithm, Perple_X. Bulk mantle compositions are systematically varied in terms of relative abundances of Mg, Si, Ca, Al, and Na, informed by stellar abundances, while keeping Fe and Cr constant and equal to the Earth bulk mantle. We then use the same modelling set-up to derive crustal mineralogy for bulk crust compositions based on these magmas.
Surface mineralogy primarily varies with the bulk mantle Mg/Si ratio: Si-rich mantles produce quartz- and plagioclase-dominated crusts, intermediate planets produce pyroxene- and plagioclase-dominated crusts, and Mg-rich planets produce crusts consisting of olivine, spinel, and nepheline. Increasing the abundances of Ca, Al, and Na mainly results in a widening of the clinopyroxene, spinel, and nepheline stability fields. The crusts of Mg-rich planets are experimentally under-explored, while we predict a significant fraction of all rocky exoplanets to form such crusts. Thus, additional surface reflectance spectra measurements are required to fully cover the diversity of potential rocky exoplanet surfaces and to enable accurate interpretation of future observations of their surface geology.
We further show with geodynamical simulations that the high-pressure density contrast between crustal and mantle rocks plays a first-order role in thermal and dynamical evolution of rocky exoplanet interiors. Planets with a greater density contrast tend to stabilize a layered mantle structure, where subducted crust accumulates at the bottom of the mantle, overlain by a cold, depleted, and typically ultramafic upper mantle. Calculating the density contrast between crust and mantle rocks for our sample of exoplanet compositions at a pressure of 140 GPa, we find that most Mg-rich planets form crusts that are significantly denser than the residual mantle, forming such a double-layered mantle structure. Meanwhile, the most Si-rich mantles produce granite-like crusts, which we predict to be too buoyant to subduct. Only planets with intermediate Mg/Si, which includes the solar system planets, have crustal buoyancy that allows for subduction and mixing of subducted crust with the mantle on geological timescales. Thus, constraining rocky exoplanet crust mineralogy and density is essential for understanding their long-term evolution and for interpreting spectroscopic observations of such planets, which is possible with JWST.
How to cite: Spaargaren, R., Manjon Cabeza Cordoba, A., Ballmer, M., and Lichtenberg, T.: Modelling surface mineral diversity of atmosphere-free rocky exoplanets for spectroscopic characterisation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18054, https://doi.org/10.5194/egusphere-egu25-18054, 2025.
Three-dimensional (3D) mapping of planetary surfaces is critical for exploration missions and scientific research (Gwinner et al., 2016). Previous research mainly focused on employing rigorous techniques such as photogrammetry and photoclinometry to generate topographic products such as digital elevation models (DEMs). While the integration of these two techniques can yield detailed and precise topographic data, photoclinometric algorithms are heavily dependent on radiometric data and surface reflectance behaviors (Chen, Hu, et al., 2024; Liu and Wu, 2023), which limits their use in different circumstances. This paper undertakes a new endeavor to explore the potential of the emerging 3D Gaussian splatting techniques for a detailed reconstruction of planetary surfaces from orbiter images.
Gaussian Splatting has demonstrated outstanding performance in 3D applications for close-range scenes and has recently attracted significant attention. The primary challenge in utilizing 3D Gaussian Splatting for the reconstruction of planetary surfaces from orbiter images lies in the complexity of the planetary push-broom camera models. The sophisticated camera model and projection algorithm complicate this optimization approach. To address this, a two-step approach is proposed to transform the planetary push-broom images into frame-like images. First, photogrammetry is applied to push-broom images to extract precise 3D topography, which is then textured using the corresponding textures from the orthoimages. From the textured 3D landscape, frame images are rendered with careful consideration of overlapping and lighting conditions to better support 3D reconstruction tasks. For surface reconstruction, the 2D Gaussian splatting method (Chen., Li., et al., 2024) is selected and implemented in a coarse-to-fine manner, incorporating a smoothness loss to ensure its suitability for textureless planetary surfaces. In addition to utilizing information from the images, the algorithm also takes into account the camera geometry derived from the previous two steps for improved 3D surface reconstruction.
Experiment analysis is conducted using HiRISE images covering the Jezero crater on Mars. The photogrammetric DEM is generated at a resolution of 1 meter per pixel, and the original images are rectified and mosaicked at their native resolution of 0.25 meters per pixel. A total of 421 frame images are rendered, ensuring high overlapping (e.g., one point appears in eight rendered images) coverages. Compared to the photogrammetric DEM, the DEM generated by 3D Gaussian splatting reveals more subtle topographic details and maintains geometric accuracy.
Reference
Chen, D., Li, H., Ye, W., Wang, Y., et al., 2024. PGSR: Planar-based Gaussian Splatting for Efficient and High-Fidelity Surface Reconstruction. arXiv preprint arXiv:2406.06521.
Chen, H., Hu, X., Willner, K., Ye, Z., et al., 2024. Neural implicit shape modeling for small planetary bodies from multi-view images using a mask-based classification sampling strategy. ISPRS Journal of Photogrammetry and Remote Sensing 212, pp. 122-145.
Liu, W.C., Wu, B., 2023. Atmosphere-aware photoclinometry for pixel-wise 3D topographic mapping of Mars. ISPRS Journal of Photogrammetry and Remote Sensing 204, pp. 237-256.
Gwinner, K., Jaumann, R., Hauber, E., Hoffmann, et al., 2016. The High Resolution Stereo Camera (HRSC) of Mars Express and its approach to science analysis and mapping for Mars and its satellites. Planetary and Space Science 126, pp. 93-138.
How to cite: Li, Z., Wu, B., and Chen, S.: 3D Gaussian Splatting for Detailed Reconstruction of Planetary Surfaces from Orbiter Images, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2216, https://doi.org/10.5194/egusphere-egu25-2216, 2025.
In orbit since the April 2018, the Colour and Stereo Surface Imaging System (CaSSIS) on board of the ExoMars Trace Gas Orbiter (TGO) has recently entered its 6th year of scientific phase. Since then, CaSSIS has provided us with a rich catalog of up to four bands stereo images of the Martian surface. The stereo capability is achieved through an innovative telescope rotation approach composing a convergence angle of almost 22 degrees between the stereo couple. In this way CaSSIS can produce detailed color 3D maps, thus providing crucial data for the analysis of the surfaces and their composition.
The pipeline for three-dimensional modelling is developed and maintained by the INAF team located at the Astronomical Observatory of Padova, making available the Digital Terrain Models (DTMs) and orthorectified images to the entire team and scientific community since the start of the mission.
The 3DPD software (Simioni et al., 2021; Re et al., 2022), at the core of the pipeline, allows the exploitation of data according to the principles of stereogrammetry. The DTMs are produced at 13.5 m ground sample distance from 4.5 m/px images, with an estimated vertical accuracy below 3 pixels size (15 m) (Fig.1).
To date, more than 2100 stereo couples are available on a total of 40.000 images acquired. Of these about 400 stereo pairs have already been processed and available for download at the OAPD-hosted repository (https://cassis.oapd.inaf.it/archive/).
Since the framework was first founded by Simioni et al., 2021, the pipeline has been continuously developing to improve the performance of the data product generation.
The goal of this work is to present the actual state of the framework and all the improvements made. Recent changes are here described and supported by an assessment of the quality and precision of the generated products and their derivatives.
Recent developments include the integration of the Bundle Block Adjustment, employing the jigsaw routines made available with the USGS ISIS platform (Laura et al., 2023). Thanks to the jigsaw output, we are able to refine the projection matrices affected otherwise by distortions that introduce geometric effects of misalignments between the acquisitions. The misalignments not adequately modelled and resolved by the Bundle Adjustment could otherwise result in steps artefacts that can reach even hundreds of m in the worst cases.
Further important update is given by an innovative approach of aligning DTMs to MOLA-HRSC (Fergason et al., 2018), further improving the surface projection and the absolute elevation, reaching values generally below 50 m/px of standard deviation in comparison with it. This process was also extended to the entire database of DTMs already produced as one major update, bringing similar results (Fig.2).
Fig.1 Comparison between a CaSSIS DTM (MY34_003673_018) and a HiRISE DTM (DTEEC_005533_1975_005388_1975) at 1 m/px, demonstrating a vertical accuracy of about 8m.
Fig.2 The standard deviation on the vertical accuracy, achieved as a result of the recent alignment with the MOLA-HRSC and applied to the entire CaSSIS DTMs database.
How to cite: Tullo, A., Re, C., Simioni, E., Bertoli, S., La Grassa, R., Cremonese, G., and Thomas, N.: Updates to the TGO-CaSSIS Stereo Products Generation and the INAF public catalog of DTMs, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19966, https://doi.org/10.5194/egusphere-egu25-19966, 2025.
Lunar cold spots are thermal anomalies associated with fresh impact craters and understanding them offers critical insights into the Moon's surface evolution and thermophysical properties. Traditionally, their detection has relied on manual methods, which are labor-intensive and time-consuming. This study evaluates the performance of two advanced deep learning-based object detection models, YOLOv8 and YOLOv11, for automating lunar cold spot detection using Diviner radiometer data. The training dataset was generated from 128-pixel-per-degree (ppd) rock-free nighttime regolith temperature maps covering latitudes up to ±60°. The dataset included 384 lunar images with 652 annotated cold spots for model training. For testing, the 2023 High-Resolution Nighttime Temperature dataset was cropped into 512×512-pixel sub-images (~4×4 degrees) with a 20% overlap to capture edge cold spots. This process generated 4,816 sub-images, ensuring comprehensive coverage and minimizing missed detections.
The experimental design included two strategies: a straightforward train-test split and a more robust 5-fold cross-validation approach. The models were assessed using key performance metrics: precision, recall, F1 score, and mean Average Precision (mAP). YOLOv11 consistently outperformed YOLOv8 across most metrics, achieving a precision of 0.85, recall of 0.78, F1 score of 0.81, and mAP-50 of 0.79 with K-fold cross-validation. Both models demonstrated superior performance in detecting faint thermal anomalies, showcasing their capability to identify subtle features often overlooked by manual methods.
Hyperparameter tuning and robust preprocessing techniques, including overlapping sub-image and data augmentation, contributed significantly to the models' performance. YOLOv11's higher selectivity resulted in fewer false positives and greater reliability, whereas YOLOv8 identified a larger number of cold spots, though with a higher false positive rate. Both models significantly outperformed manual detection methods, demonstrating their ability to expand the catalog of lunar cold spots efficiently and accurately with precision of 78% and 89% for YOLOv8 and Yolov11, respectively. This automated approach identified previously undetected cold spots, providing a more comprehensive understanding of lunar thermal anomalies and their spatial distribution.
These findings highlight the transformative potential of convolutional neural networks (CNNs) in planetary science, particularly in automating complex and data-intensive tasks like lunar cold spot detection. The scalability and precision of YOLOv11, combined with YOLOv8's sensitivity to faint anomalies, underscore the value of integrating deep learning techniques into planetary exploration and research.
How to cite: Weil Zattelman, S. and Kizel, F.: COMPARATIVE ANALYSIS OF YOLOv8 AND YOLOv11 FOR COLD SPOT DETECTION ON THE LUNAR SURFACE, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12535, https://doi.org/10.5194/egusphere-egu25-12535, 2025.
The island of Lanzarote (Canary Islands) is widely recognized as a terrestrial analog for planetary science due to its geological and environmental characteristics. This island hosts numerous lava tubes, including the 7.6-km-long La Corona tube, one of Earth’s largest. Detecting lava tubes and other subsurface cavities is crucial for planetary exploration, as they may be used as safe shelters in future planetary missions.
Magnetic data, including scalar and vector magnetometer data as well as magnetic susceptibility measurements, were collected during the NASA Goddard GeoLife expedition in May 2023 to study three lava tubes of different morphometry, age, and geological features: La Corona, Los Naturalistas, and Tahiche. This study focuses on analyzing vector magnetometer measurements over La Corona tube. We rotate and process the vector magnetic measurements to derive magnetic anomalies of both the total magnetic field and the individual vector components. To identify, delineate, and characterize the lava tube, we apply various enhancement techniques such as calculating the reduction to the pole or the lateral derivatives.
Our findings reveal the feasibility of using vector magnetometer data to detect lava tubes. Additionally, we show that our magnetic anomaly values derived from vector magnetometer data are comparable to those obtained from scalar magnetometer data. Lastly, we illustrate that we can extract valuable information from each of the vector magnetic field components and use them together with the total field values to identify and interpret magnetic subsurface features.
How to cite: Martin de Blas, J., Martos, Y. M., Espley, J., Richardson, J., Sheppard, D., and Connerney, J.: Magnetic signature of La Corona lava tube (Lanzarote, Canary Islands) as a planetary analog, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6513, https://doi.org/10.5194/egusphere-egu25-6513, 2025.
Hydromagmatic eruptions are of particular importance for the search of extraterrestrial life since they require the presence of water. Phreatomagmatic volcanoes on Mars shall resemble those of the Earth and thus, terrestrial analogues of Mars, such as Lanzarote in the Canary Islands, are a good reference for further studies of the Martian volcanoes.
In this study we present our drone-based magnetic survey results combined with a morphometric analysis of Caldereta horse-shoe shaped volcano in Lanzarote, catalogued as a phreatomagmatic tuff for its similarity and proximity to Caldera Blanca, a well-known hydromagmatic edifice (Barrera Morate et al., 2011; Carracedo and Day, 2002; Romero et al., 2007; Kervyn et al., 2012; Brož and Hauber, 2013). On Mars, the chosen edifice is C27 volcano, a horse-shoe shaped cone in the Nephentes/Amenthes region, whose pitted cones were suggested to be of phreatomagmatic origin by Brož and Hauber (2013).
Our morphometric analyses allowed us to classify both Caldereta and C27 edifices as tuff rings, specifically maars. With the drone-based survey performed in Caldereta we demonstrate how more insights could be gained from Martian volcanos when combining magnetic surveys using helicopters on Mars (Mittelholz et al., 2023) with morphometric analyses using satellite data and high-resolution near surface geophysical studies.
Keywords
Magnetometry, Mars, planetary magnetism, crustal magnetism, Mars hydromagmatism, planetary science, space magnetometers.
References:
Barrera Morate J.L., García Moral R., 2011. Mapa geológico de Canarias. GRAFCAN. https://www.idecanarias.es/resources/GEOLOGICO/LZ_LITO_unidades_geologicas.pdf
Brož, P., Hauber, E., 2013. Hydrovolcanic tuff rings and cones as indicators for phreatomagmatic explosive eruptions on Mars. J. of Geophys. Res.: Planets 118, 1656–1675. doi: 10.1002/jgre.20120.
Carracedo, J.C., Day, S., 2002. Canary Islands, in: Classic Geology in Europe Series 4. Terra Publishing, Harpenden, Hertfordshire, p. 294.
Kervyn, M., Ernst, G.G.J., Carracedo, J.C., Jacobs, P., 2012. Geomorphometric variability of “monogenetic” volcanic cones: Evidence from Mauna Kea, Lanzarote and experimental cones. J. Geomorphol. 136, 59-75. https://doi.org/10.1016/j.geomorph.2011.04.009
Mittelholz, A., Heagy, L., Johnson, C. L., Fraeman, A. A., Langlais, B., Lillis, R. J., and Rapin, W.: Helicopter Magnetic Field Surveys for Future Mars Missions, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11186, https://doi.org/10.5194/egusphere-egu23-11186, 2023.Romero, C., Dóniz, J., García Cacho, L., Guillén, C., Coello, E., 2007. Nuevas evidencias acerca del origen hidromagmático del conjunto volcánico Caldera Blanca/Risco Quebrado (Lanzarote, Islas Canarias). Resúmenes XII Reunión Nacional de Cuaternario, Ávila.
How to cite: Díaz-Michelena, M., Losantos, E., Rivero, M. Á., Oliveira, J. S., García Monasterio1, Ó., Mansilla, F., Melguizo, Á., García Bueno, J. L., Salamanca, D., and Fernández Romero, S.: Geophysical investigation of the terrestrial analogue, Caldereta volcano, in Lanzarote, the Canary Islands as a precursory study to mars phreatomagmatic volcanoes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10842, https://doi.org/10.5194/egusphere-egu25-10842, 2025.
Extensive physical and chemical evidence from orbiter, lander, and rover data show that surface water was widespread on Mars into the Amazonian. Alluvial fans are geologic landforms on Mars that preserve evidence of this late-stage aqueous activity in the geologic record. The composition and distribution materials in an alluvial fan, either in the catchment (source) and/or the fan (sink), help inform our understanding of the origin and extent of aqueous alteration, either in the source rocks prior to deposition or after, in the fan itself. However, the geochemical and mineralogical properties of martian alluvial fans, and how these properties vary from the catchment to the fan, are not well constrained.
The work presented here characterizes the geochemistry and mineralogy of two alluvial fans and their associated catchments at sites in Iceland—Fjallabak and near Hoffellsjökull—which serve as close compositional analogs for Mars. These results can help us to understand the aqueous alteration that formed similar deposits on Mars while placing constraints on martian geologic history and paleoclimate.
We utilize a suite of complementary laboratory techniques: Raman spectroscopy, scanning electron microscopy with an energy dispersive X-ray detector (SEM/EDS), and X-ray diffraction (XRD). Raman spectroscopy qualitatively maps spectral properties to confirm existing mineral identification and spectra are processed to determine the relative abundance materials; this technique is of particular use to identify amorphous glass. SEM/EDS is used to quantitatively map elemental compositions, and XRD with Rietveld refinement can identify the type and abundance of crystalline minerals. Raman and XRD both have in situ instrument analogs on the surface of Mars: the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) on the Perseverance rover, and Chemistry and Mineralogy (CheMin) instrument on the Curiosity rover, respectively. SEM/EDS techniques are also likely to be applied to samples returned from Mars.
At Fjallabak, source rocks are primarily a combination of hyaloclastite (a product of subglacial volcanism) and rhyolite. At Hoffellsjökull, the rocks are mostly basalt with evidence of minor hydrothermal alteration. Rocks and sediments do not appear to be heavily altered upon deposition into the alluvial fan, although some authigenic alteration may have occurred in the catchment itself.
Preliminary Raman spectral analyses support our initial field interpretations of the rocks and minerals observed at both field sites. To date, we have analyzed hyaloclastite source rocks and confirmed the presence of obsidian and/or albite glass, along with signs of aqueous alteration indicated by Fe-oxides (i.e., goethite) at Fjallabak. We have also identified diopside (Ca-Mg clinopyroxene) and actinolite (a low-grade metamorphic mineral) in inferred hydrothermally altered basalt, along possible Fe-oxide-hydroxides (i.e., lepidocrocite) that indicate aqueous alteration in the Hoffellsjökull fan. Initial results suggest aqueous alteration of materials at both field sites but the distribution of primary versus secondary materials has yet to be constrained.
Our results will include the laboratory analysis that characterize these Iceland fans that will help determine the extent and distribution of alteration products in alluvial fans at Mars compositional analog sites.
How to cite: Rudolph, A., Haber, J., Wilson, S., Irwin, R., Morgan, A., Horgan, B., Rose, T., and Wardell, R.: Geochemical and Mineralogical Signatures of Alluvial Fans in Iceland and their Implications for Late Stage Aqueous Activity on Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13284, https://doi.org/10.5194/egusphere-egu25-13284, 2025.
Fan-shaped deposits, including alluvial fans and deltas, are abundant on Mars. They preserve evidence of episodic running water and potentially habitable environments into the early Amazonian. Most alluvial fan analog studies have focused on depositional processes, rather than the composition of fan materials. In particular, it is unclear if the composition of fan deposits represents alteration during transport/deposition or the composition of the watershed in a cold environment.
In this study, we use a suite of remote sensing techniques to characterize mineralogy of rocks and sediments in alluvial fans in Iceland to understand any distinct trends within this tundra climate. This work helps fill a knowledge gap for understanding alluvial fans on Mars through the novel analog study in a cold climate on Earth. Iceland has been widely studied as a Mars analog because of its dominant basaltic composition, general lack of vegetation, and tundra climate. We analyze several alluvial fans of variable morphology, location, and composition to understand how these factors might affect the alteration of fan sediments.
Prior to fieldwork, we analyzed high-resolution orbital images (15 m/pixel) from the World Imagery ESRI Basemap and spectral data (10-60 m/pixel) from the SENTINEL-2 MultiSpectral Instrument in the visible to near infrared (VNIR) range (13 bands; 0.443-2.190 μm) to characterize decameter-scale compositional variability.
During our July 2024 field season, we imaged fans and their watersheds using a DJI Mavic Pro 2 drone at the meter- to decameter-scale. We used a portable ASD QualitySpec Trek spectrometer to collect VNIR (0.35-2.5 μm) reflectance spectra and identify minerals along transects from the fan apex to toe to capture compositional variability in the fan deposits and their watersheds.
Our results focus on two alluvial fans and their watersheds: one dominated by rhyolite and hyaloclastite in Fjallabak Nature Reserve in the Icelandic highlands and another dominated by basalt near Hoffellsjökull in eastern Iceland. In VNIR spectra from Fjallbak, we observe absorption bands due to hydration (1.4 and 1.9 μm), Fe-oxides (0.53 and ~0.9 μm), and hydrated silica (2.2 μm). At Hoffellsjökull, we also observe kaolinite (2.2 μm doublet) in tan rocks and calcite (2.338 μm) in veins and vesicles within basalt. We also observe broad absorptions near 1 and 2 μm likely due to primary mafic minerals such as olivine, pyroxene, or volcanic glass.
Our results indicate that rocks in the alluvial fans were sourced from a variety of lithologies, which we are able to identify in the watershed using drone and orbiter images. Overall, we do not observe major differences in composition between the fan deposits and their watersheds, suggesting that there is minimal alteration during transport and deposition. Ongoing work includes detailed spectral analyses of sediments along fan transects and comparisons to the watershed to determine how the rocks and sediments vary across the fan deposit. Additionally, comparisons to similar alluvial fans on Mars will improve our understanding of how these features may have formed in a cold climate.
How to cite: Haber, J., Rudolph, A., Irwin, R., Morgan, A., Horgan, B., and Wilson, S.: Using Remote Sensing to Understand Icelandic Alluvial Fan Composition as an Analog for a Cold and Wet Ancient Mars, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13316, https://doi.org/10.5194/egusphere-egu25-13316, 2025.
The VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) mission is a future NASA Discovery mission that aims to improve our understanding of Venus' evolution, structure, and geological processes. Its gravity science experiment will produce a uniform, high-resolution gravity map of Venus, providing unprecedented constraints on the planet’s crustal and interior structure. The radio tracking relies on a dual-frequency transponder in X and Ka bands. This advanced multi-frequency system achieves Doppler measurement accuracy of about 18 μm/s (for most of the mission duration) at 10-second integration time and can correct 75% of the plasma noise, particularly important at low Sun-Probe-Earth (SPE) angles (<15-20°).
Numerical simulations of the VERITAS gravity experiment were carried out using JPL’s MONTE software, considering detailed dynamical and noise models. The noise model accounts for 1) media propagation effects, i.e., troposphere, ionosphere, and plasma, where troposphere has a seasonal variation and plasma noise depends on SPE angle, and 2) spacecraft and ground station instrumentation. While many noise sources have a white noise spectral profile, significant contributors such as the frequency and timing system (FTS) and plasma introduce colored noise, i.e., whose magnitude varies with frequency.
A colored-noise results in a non-diagonal correlation matrix which can bias (with respect to a white-noise case) the best-fit estimated parameters and lead to an underestimation of their uncertainties.
Therefore, the main objective of this work is to evaluate the impact of colored noise on the estimation of the parameters related to the Venus’ gravity field (i.e., the spherical harmonic coefficients).
To this aim, we simulated the Doppler observables and the gravity recovery for both the white-noise and colored-noise cases. Colored noise was simulated with the algorithm described by [1] and we developed a method to incorporate these correlations into the sequential filtering process used for orbit determination. We will present the results of these simulations.
[1] Timmer, J. and Koenig, M. (1995). On generating power law noise. Astronomy and Astrophysics, 300:707.
How to cite: De Marchi, F., Giuliani, F., Durante, D., Cascioli, G., Iess, L., Mazarico, E., and Smrekar, S.: VERITAS Gravity Science Experiment: Impact of Colored Noise on Parameter Estimation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12405, https://doi.org/10.5194/egusphere-egu25-12405, 2025.
By computing the tidal deformations of Mars, we investigated its spherically symmetric internal structure, and specifically the nature (liquid, partially melted or both) of the interface between the mantle and the liquid core. Through an evaluation of their compatibility with diverse geophysical observations, we demonstrated that, despite the short excitation periods, tidal deformation (tidal dissipation induced by Phobos and tidal quality factor at the Phobos excitation frequency) provides an effective means to constrain Mars's internal structure. Our analysis yielded independently density and thickness estimates for the Martian lithosphere, mantle, core–mantle boundary layers, and core, which were consistent with previous results from other methods. Additionally, we derived new viscosity estimates for these layers. Notably, we showed that geodetic observations, combined with thermal constraints, are particularly sensitive to the presence of a two-layered interface at the top of the liquid core in the deep Martian mantle. This interface comprises two layers with similar densities but very different viscosities and rheologies. The layer directly atop the liquid core follows a Newtonian constitutive equation (Newtonian Basal Layer or NBL), while the overlying layer at the base of the mantle has an Andrade rheology (Andrade Basal Layer or ABL), characterized by a viscosity approximately 10 orders of magnitude greater than that of the Newtonian layer. Our results indicate that the presence of this two-layered interface significantly affects the viscosity profiles of both the mantle and lithosphere. Specifically, models incorporating the two-layered interface show small viscosity contrast between the mantle and the lithosphere, preventing mechanical decoupling between these layers. This would support a stagnant lid regime, consistent with the current absence of Earth-like plate tectonics on Mars. Finally, our findings suggest that the presence of a liquid Newtonian layer atop the liquid core is incompatible with the existence of a solid inner core on Mars.
How to cite: Ganino, C., Guinard, A., Fienga, A., and Mémin, A.: How tidal tomography and thermal constraints can probe the existence of a Martian basal molten layer, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11941, https://doi.org/10.5194/egusphere-egu25-11941, 2025.
Gravity inversion techniques enable the characterisation of the internal mass distribution of planetary bodies by combining data from their shape, gravity, and rotation. However, the inherent ambiguity in scalar gravity signals, specifically, between mass and depth, poses a significant challenge for inferring internal structure. In this work, we introduce a novel approach leveraging the spherical harmonics framework described in [1], in particular, the gravitational harmonics coefficients [Cnm, Snm]. Starting with a simplified interior structure (assuming homogeneous layers), interior model parameters are the number of layers, average layer thickness, average layer density, and the topography of layer interfaces (if present). Regarding the latter, in cases where Bouguer anomalies are available, the mantle-crust interface topography can be inferred using a filtering approach, as proposed in [2]. Notably, this method does not rely on assumptions of isostatic compensation but requires careful selection of the filtering parameters. From these parameters. the spherical harmonics coefficients for each layer and the global ones are computed (see [1]). From these coefficients, key quantities such as gravitational potential, Free-Air anomalies, and Bouguer anomaly maps are evaluated and then compared to space measurements, measuring the model performance by different metrics (e.g. RMSE, structural similarity index, Pearson correlation coefficient). By varying model parameters randomly within physically constrained ranges (e.g. by mass conservation, moment of inertia and observed shape), this process is repeated iteratively. The parameter combination minimizing the performance metrics between modelled and observed data represents the best-fit internal structure. This approach is robust and flexible at the same time, being able to accommodate diverse celestial bodies with a wide variety of planetary shapes, internal configurations, and gravitational data sets and to objectively identify the optimal parameter configuration. This method is benchmarked on Mercury [3], resulting in a mantle-crust interface at ~28 km depth and a mantle density of 3210 [kg/m3], consistent with existing literature (see [4]). Furthermore, this procedure can be used to compute the expected gravity signal from unknown bodies targeted by the upcoming missions and instruments (e.g. Ganymede for JUICE), test different theoric interior models, and obtain their gravitational response.
Acknowledgements: ESM and GM acknowledge support from the Italian Space Agency (2022-16-HH.1-2024). This paper and related research have been conducted during and with the support of the Italian national inter-university PhD programme in Space Science and Technology.
References: [1] M. A. Wieczorek, ‘Gravity and Topography of the Terrestrial Planets’, in Treatise on Geophysics, Elsevier, 2015, pp. 153–193. doi: 10.1016/B978-0-444-53802-4.00169-X.[2] M. A. Wieczorek and R. J. Phillips, ‘Potential anomalies on a sphere: Applications to the thickness of the lunar crust’, Journal of Geophysical Research: Planets, vol. 103, no. E1, pp. 1715–1724, 1998, doi: 10.1029/97JE03136.[3] A. Genova et al., Regional variations of Mercury’s crustal density and porosity from MESSENGER gravity data, Icarus, vol. 391, p. 115332, Feb. 2023.[4] S. Buoninfante, M. Milano, B. Negri et al. ‘Gravity evidence for a heterogeneous crust of Mercury’. Sci Rep 13, 19854 (2023), https://doi.org/10.1038/s41598-023-46081-4
How to cite: Santero Mormile, E. and Mitri, G.: Planetary Interior Modeling Using Synthetic Gravity Simulator, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8720, https://doi.org/10.5194/egusphere-egu25-8720, 2025.
The surface and crustal structure of the terrestrial planets in the inner solar system have been influenced by large and energetic impact events. GRAIL data showed that the size of the central gravitational anomaly of lunar basins corresponds closely to the diameter of the inner peak-ring [1].
We present an improved technique based on the analysis of gravity and crustal thickness data to estimate the inner ring and rim crest diameters. This technique expands upon the work of [1] and allows us to better identify highly degraded basins. From this analysis, we also quantify how lower resolution gravity and crustal thickness datasets (such as for Mars and Mercury) might bias the peak ring and main rim diameter estimates.
In our approach, we first quantify the regional value of the Bouguer gravity anomaly and crustal thickness, which is defined as the average value obtained from azimuthally averaged profiles in the radius range 1.5 D to 2 D, where D is the crater diameter. The diameter of the Bouguer gravity high, as well as the diameter of the crustal thickness anomaly, were then estimated as the radius where the profiles first intersect the background regional values. After the initial estimate of D was obtained, the procedure was iterated until there was no change in the obtained diameters.
We tested this method using Bouguer gravity data for certain lunar peak-ring and multi-ring basins, by considering the spherical harmonic degree range from 6 to 540. We then filtered the data using the spherical harmonic degree range 6-49 in order to simulate the lower resolution of the Mars gravity models (e.g., [2]). We then used the same approach using crustal thickness maps derived after GRAIL [3], both for the degree ranges 6-310 and 6-46, to simulate the loss of spatial resolution of Mars [4]. Uncertainty estimates were obtained for the crustal thickness and the Bouguer anomaly diameter by considering the ±1σ values for the background values in the spatial range of 1.5 D to 2 D.
Our method properly detects peak-ring or inner ring sizes for lunar basins with main rim diameter greater than 250 km. Nevertheless, when considering filtered versions of these datasets that correspond to the effective spatial resolution of the Mars gravity models, only basins with rim crest diameters greater than about 450 km can be detected with acceptable accuracy. Finally, results from these analyses will allow us to better constrain the impact rate during the early solar system.
References:
[1] Neumann G. A., et al. (2015). Sci. Adv.
[2] Genova A., et al. (2016). Icarus.
[3] Wieczorek M. A., et al. (2013). Science.
[4] Wieczorek M. A., et al. (2022). JGR: Planets.
Acknowledgements: We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2024-18-HH.0.
How to cite: Buoninfante, S., Wieczorek, M. A., Galluzzi, V., Ferranti, L., Milano, M., Fedi, M., and Palumbo, P.: Quantifying the size of impact basins through analysis of gravity and crustal thickness data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6291, https://doi.org/10.5194/egusphere-egu25-6291, 2025.
Mercury boasts a variety of infilled craters, several of which contain central depressions surrounded by unique, bulged, ring-like structures. These rings are comprised of the infill itself, range in size and elevation, and can often exceed the crater rim in which they are contained (e.g. Bryne et al., 2014). Although peak ring crater types are common across Mercury (e.g. Baker et al., 2011; Schon et al., 2011), these bulged infill rings represent an entirely different morphology which represents a process that occurs after the crater and potential peak ring is formed. These bulged rings often present concentric extensional faults on their summits, and in some cases the accompanying central depression contains radial or circular extensional faults (e.g. Cunje & Ghent, 2016; Marchi et al., 2011). The formation process of this topography remains unknown and difficult to constrain, however it has been previously suggested that global contraction could aid their formation (Byrne et al., 2014). However, the weight load of the infill itself has yet to be fully appreciated as a candidate for tectonic processes on Mercury, particularly in the creation of bulged topography (Schmidt & Salvini, 2024). Additionally, lava entry pathways (i.e. lava which exploits circular normal faults within the interior of the craters) may play a role. By analyzing nine craters (four exhibiting the bulged infill topography, four exhibiting peak ring topography, and one seemingly intermediate type of topography) we aim to determine the relationship between bulged rings within infill and their more common peak ring topography counterparts. In so doing, we can determine if this infill topography is merely a lava infill which has conformed to a pre-existing peak ring, or if the weight load of the infill at the center of the crater has the potential to create an elastic response which creates the bulged ring and simultaneously the central depression.
We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2024-18-HH.0
Baker et al. (2011) The transition from complex crater to peak-ring basin on Mercury: New observations from MESSENGER flyby data and constraints on basin formation models. Planetary and Space Science, 59(15), 1932-1948.
Byrne et al. (2014) Mercury’s global contraction much greater than earlier estimates. Nature Geoscience, 7(4), 301-307.
Cunje & Ghent (2016) Caloris basin, Mercury: History of deformation from an analysis of tectonic landforms. Icarus, 268, 131-144.
Marchi et al. (2011) The effects of the target material properties and layering on the crater chronology: The case of Raditladi and Rachmaninoff basins on Mercury. Planetary and Space Science, 59(15), 1968-1980.
Schmidt & Salvini (2024) Thickness of Pluto's Ice Shell from elastic deformation of the Sputnik Planitia forebulge: Response to infill load or vestige of impact event?. Earth and Planetary Science Letters, 646, 118974.
Schon et al. (2011) Eminescu impact structure: Insight into the transition from complex crater to peak-ring basin on Mercury. Planetary and Space Science, 59(15), 1949-1959.
How to cite: Schmidt, G., Buoninfante, S., Galluzzi, V., and Palumbo, P.: Categorization of ring and bulge topographies of infilled craters on Mercury, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20078, https://doi.org/10.5194/egusphere-egu25-20078, 2025.
Mercury's unique orbital dynamics, influenced by its proximity to the Sun and high eccentricity, lead to periodic variations in tidal forces and surface temperature patterns. The tidal Love numbers (TLNs), which characterize the planet's deformation and gravitational field changes, are highly sensitive to key internal parameters such as core size, mantle composition and rheology, and the presence of lateral and vertical heterogeneities e.g., [1-5]. Mercury's TLNs thus provide a quantitative framework for understanding how its internal structure responds to tidal forces. In this study, we systematically investigate how variations in these internal parameters affect Mercury's TLNs. We use numerical models to simulate the tidal response of the planet, taking into account a wide range of geophysical and thermodynamic conditions. In particular, we investigate the effects of core-mantle interactions, variations in mantle viscosity and temperature, and potential anisotropies within the lithosphere. Our results show that TLNs are particularly influenced by the size and state of the core, the thermal gradient across the mantle, and the degree of lateral heterogeneity within the inner layers. To validate and refine our models, we will integrate these results with observational constraints such as Mercury's mean density, moment of inertia, and surface deformation data e.g., [1, 6]. This study will provide important insights for interpreting future high-precision measurements from the BepiColombo mission [7]. By linking TLNs to Mercury's internal parameters, we aim to develop a robust framework for constraining the planet's internal structure, providing a deeper understanding of its geodynamic evolution and its significance in the broader context of the formation and evolution of terrestrial planets.
References:
[1] Goossens et al., 2022. The Planetary Science Journal, 3(6), 145.
[2] Mazarico et al., 2014. Journal of Geophysical Research: Planets, 119(12), 2417-2436.
[3] Mosegaard and Tarantla, 1995. Journal of Geophysical Research: Solid Earth, 100(B7), 12431-12447.
[4] Steinbrügge et al., 2018. Journal of Geophysical Research: Planets, 123(10), 2760-2772.
[5] Rivoldini et al., 2009. Icarus, 201(1), 12-30.
[6] Genova et al., (2019), Geophysical Research Letters, 46(7), 3625-3633.
[7] Hussmann and Stark, (2020), The European Physical Journal Special Topics, 229, 1379-1389.
How to cite: Briaud, A., Stark, A., Hussmann, H., Xiao, H., and Oberst, J.: Quantifying Mercury's tidal response: A framework for understanding planetary interiors, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10169, https://doi.org/10.5194/egusphere-egu25-10169, 2025.
Mercury's annual longitudinal libration (88 days) and its mean rotation rate have been determined based on independent observations from the ground-based radar (Margot et al., 2012), camera and/or laser altimetry (Stark et al., 2015; Bertone et al., 2021), and radio science (Mazarico et al., 2014; Genova et al., 2019; Konopliv et al., 2020). Although consistent, the precision of the libration measurements precludes identification of a large solid inner core (Van Hoolst et al., 2012). At the same time, the measured rotation rates are largely inconsistent. Deviation from the resonant rotation rate is caused by the planet-induced long-term librations which can be amplified if their periods are close to that of a free libration mode (Yseboodt et al., 2013).
We devise an alternative and innovative approach aimed at precisely tracking how the rotation angle varies with time so that various libration terms can be analyzed quantitatively. The approach involves two self-registration processes of the MESSENGER Mercury Laser Altimeter (MLA) profiles (Xiao et al., 2024). We focus on a small polar region from 81°N to 84°N. In the first step, we carry out the self-registration by shifting the individual profiles laterally and radially to get rid of the slow-varying orbit, pointing, and timing errors, which can be treated as near-constant. In contrast to the aforementioned near-constant shifts, offsets in the rotation angles can lead to non-linear rotation-like distortions of the profiles. Offsets in the orientation angles of the spin axis can shift the profiles as a whole, ensuring that our approach is insensitive to the a priori orientation state. Then in the second step, we update the inertial coordinates of the profiles and perform the second self-registration in which adjustments are made to the rotation angles at the acquisition times of each of the profiles. However, as the periapsis of the spacecraft has drifted throughout the mission, the ground track does not exactly cross the North Pole and an offset in the rotation angle can also shift the centroid of the profile. In the light of this, the above two-step process needs to be iterated till convergence. Finally, we obtain the updated rotation angle per profile uncontaminated by external error sources.
We have experimented with various a priori rotation and orientation values, i.e., Stark2015, IAU2015 (Archinal et al., 2018), Genova2019, and Bertone2021. An example of the obtained variation of the rotation with time is shown in Figure 1. The long-term libration most likely to be amplified and captured is that with a period of around 6 years, induced by Venus (5.66 y), or by Jupiter (5.93 y), or by the Earth (6.57 y). The superposition of multiple long-period terms is also possible. We will carry out close-loop simulations to assess uncertainty and consider interior and libration modelings to interpret the scientific implications.
Figure 1: Rotation variation with time using the IAU2015 model as a priori values. Correction is with respect to Mercury’s resonant rotation.
References:
Archinal et al., 2018. Celest. Mech. Dyn. Astron.. Bertone et al., 2021. JGR. Mazarico et al., 2014. JGR. Genova et al., 2019. GRL. Konopliv et al., 2020. Icarus. Margot et al., 2012. JGR. Stark et al., 2015. GRL. Van Hoolst et al., 2012. EPSL. Xiao et al., 2024. Authorea Preprints. Yseboodt et al., 2013. Icarus.
How to cite: Xiao, H., Stark, A., Bertone, S., Rivoldini, A., Baland, R.-M., Yseboodt, M., Stenzel, O., Briaud, A., Hussmann, H., Lara, L., and Gutiérrez, P.: Mercury's annual and long-term librations from self-registration of MLA profiles , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5037, https://doi.org/10.5194/egusphere-egu25-5037, 2025.
Illumination conditions in the lunar polar areas are highly complex. Owing to low sun elevation angles and the lack of seasons in these areas, combined with rugged topography, this may lead to Permanently Shadowed Regions (PSRs) in craters and topographic depressions, where low temperatures allow ice to accumulate [1]. In contrast, Long-term Illuminated Areas (LIAs) on high-standing ridges and crater rims enable almost uninterrupted illumination and solar power supply [2]. High-resolution Digital Terrain Models (DTMs) are crucial for modelling these illumination conditions and for general support of future polar exploration missions [3]. We choose to derive those models from images captured by the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) for LIAs and by ShadowCam for PSRs [4], [5]. Here, we use our deep learning method developed previously to derive south pole DTMs, which can achieve a similar or even better effective resolution to those produced by the SFS method [6], stereo photogrammetry, or laser altimetry. We selected Shackleton Crater (a typical PSR) and Malapert Massif (a candidate landing site for the Artemis Program) as experimental areas to derive DTMs with resolutions of 2 meters and 1 meter, respectively. Finally, we used the DTMs to perform refined illuminated modeling and analysis to support future lunar south pole exploration missions.
References:
[1] Brown, H.M., et al. (2022) Resource potential of lunar permanently shadowed regions. Icarus, 377, p.114874.
[2] Gläser, P., et al. (2018) Illumination conditions at the lunar poles: Implications for future exploration. Planetary and Space Science, 162, pp.170-178.
[3] Chen, H., et al. (2022) CNN-based large area pixel-resolution topography retrieval from single-view LROC NAC images constrained with SLDEM. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 15, pp.9398-9416.
[4] Robinson, M.S., et al. (2010) Lunar reconnaissance orbiter camera (LROC) instrument overview. Space Science Reviews, 150, pp.81-124.
[5] Robinson, M.S., et al. (2023) ShadowCam instrument and investigation overview. Journal of Astronomy and Space Sciences, 40(4), pp.149-171.
[6] Chen, H., et al. (2024) ELunarDTMNet: Efficient reconstruction of high-resolution lunar DTM from single-view orbiter images. IEEE Transactions on Geoscience and Remote Sensing, 62, pp. 1-20.
How to cite: Chen, H., Gläser, P., Willner, K., Huang, Q., Xie, X., and Oberst, J.: High-resolution Topographic Modeling for the Lunar South Pole Region Using NAC and ShadowCam Images, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3321, https://doi.org/10.5194/egusphere-egu25-3321, 2025.
With the Moon’s rotation axis almost perpendicular to the ecliptic, the lunar polar regions are in a unique position. As the Sun hovers near the horizon all year round, and given the rough morphology, this leads to very complex illumination conditions in the area. High-resolution illumination maps derived from accurate lunar terrains serve as essential tools for identifying cold traps and evaluating solar energy ― key factors for upcoming exploration missions [1], [2]. Here, we use our previously developed illumination modeling methodology [3] to produce a series of illumination maps based on Lunar Orbiter Laser Altimeter (LOLA) gridded topographic models. Benefitting from the methodological optimizations and GPU acceleration techniques, modeling efficiency is no longer a challenge. We produced maps of the average illumination and the distribution of Permanently Shadowed Regions (PSRs), the resolution and coverage of these maps are consistent with the LOLA terrains, up to a maximum resolution of 5 meters [4]. Another derivative of modeling, the artificially shaded synthetic images corresponding to illumination at any moment, can be compared with “real” image data. We selected Malapert Massif and Shackleton-de Gerlache Ridge (both near the candidate landing sites of the Artemis program) as our experimental areas, and compared our maps with previously published illumination data [1], [2]. The results show that, our higher-resolution illumination maps are visibly more informative and the corresponding synthetic images are more consistent with the illumination patterns seen in “real” images. This work can provide useful suggestions for future lunar south pole explorations and scientific research.
[1] Mazarico E., et al. (2011) Illumination conditions of the lunar polar regions using LOLA topography. Icarus, 211, pp.106681.
[2] Gläser, P., et al. (2018) Illumination conditions at the lunar poles: Implications for future exploration. Planetary and Space Science, 162, pp.170-178.
[3] Tong, XH., et al. (2022) A high-precision horizon-based illumination modeling method for the lunar surface using pyramidal LOLA data. Icarus, 390, pp.115302.
[4] Barker et al. (2023) A New View of the Lunar South Pole from the Lunar Orbiter Laser Altimeter (LOLA). The Planetary Science Journal, 4, pp.183.
How to cite: Huang, Q., Liu, S., Chen, H., Gläser, P., He, F., Oberst, J., and Tong, X.: High-resolution Illumination Maps around the Lunar South Pole, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19657, https://doi.org/10.5194/egusphere-egu25-19657, 2025.
In lunar exploration, high-resolution topography is an important basis for safe landing and mission planning. Remote sensing images are the main data sources for the reconstruction of lunar surface topography [1]. Among them, the orbiter images preserve the topographic photometric information under different illumination directions, and the descent images contain high-resolution morphological details of the landing site. In order to integrate the advantages of multi-illumination directions of orbiter images and high resolution of descent images, we propose a joint photometric-constrained method for topography reconstruction using both orbiter and descent images. In the framework of the joint photometric-constrained Shape from Shading (SfS) [2-4], the photometric information in multi-source images illuminated from different directions is added into the cost function as a weighted regular term in topography reconstruction. We focus on the Chang'E-3 landing site. We used the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images of the area and Chang'E-3 descent images for experiments, and obtained topographic data of the site with a resolution better than 0.1 m/pixel. Comparing with previously derived topography [5], we verified that our topography is more consistent result with the images in multi-angle illumination rendering [6], integrating the photometric information of the multi-source images and preserving the morphological details such as small-size impact craters. The method proposed in this study not only improves the accuracy of topography reconstruction of the Chang'E-3 landing site, but also provides a new idea for the joint processing of multi-source image data.
[1] Di K., et al. (2020) Topographic mapping of the moon in the 21st century: from hectometer to millimeter scales. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, XLIII-B3-2020, pp.1117-1124.
[2] Horn, B.K.P. (1990) Height and gradient from shading. International Journal of Computer Vision, 5, pp. 37–75.
[3] Beyer R.A., et al. (2018) The Ames Stereo Pipeline: NASA's Open Source Software for Deriving and Processing Terrain Data. Earth and Space Science, 5, pp. 537-548.
[4] Tenthoff M. et al. (2020) High Resolution Digital Terrain Models of Mercury. Remote Sensing, 12, p. 3989.
[5] Henriksen M.R., et al. (2017) Extracting accurate and precise topography from LROC narrow angle camera stereo observations. Icarus, 283, pp.122-137.
[6] Tong X., et al. (2023) A high-precision horizon-based illumination modeling method for the lunar surface using pyramidal LOLA data. Icarus, 390, p. 115302.
How to cite: Xie, X., Liu, S., Ma, L., Huang, Q., Chen, H., Oberst, J., and Tong, X.: Photometric-Constrained Reconstruction of Lunar Landing Site Topography Using Orbiter and Descent Images, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19233, https://doi.org/10.5194/egusphere-egu25-19233, 2025.
In the last few years, NASA, ESA, CNSA and JAXA have been planning comprehensive lunar initiatives, including the Artemis program. In this context, it is crucial to i) support scientific research aimed at improving our ability to collect direct ground-truth data and samples, and ii) test equipment and validate analytical methodologies at designated analogue sites. Among the sites of interest on the lunar surface are the ones dominated by pyroclastic deposits since, as shown on Apollo samples, they may have trapped considerable volumes of gases3, being their formation linked to the presence of volatiles within magma. This material represent an intriguing in-situ resource1 that has yet to be verified even considering studies on Earth analogues on volcanic environments. Some of them are well internationally-known (e.g., Lanzarote, Canary Islands4; Kilauea Volcano, USA; Lava Beds National Monument, USA) and have been extensively studied. In other cases, such as Mount Etna, the compositional similarity remains unexplored, despite the site has already attracted interest from the planetary science community2. Mount Etna volcano exhibits several geological similarities with lunar features such as the presence of lava tubes, cinder cones, lava channels and bowl shaped pits; however, its analogy from a compositional point of view has yet to be determined.
For this reason, several unweathered and unaltered samples have been collected from a pyroclastic deposit in the area of the Cisternazza pit crater, a collapse pit located on the southern flank of Mount Etna. The samples underwent comprehensive chemical and mineralogical characterization, revealing compositional similarities with lunar samples. Consequently, further tests were conducted to examine their mechanical, thermal, and spectral behaviour to compare it with lunar samples and certified lunar simulants across a broader range of properties.
To assess the analogy with the lunar surface, specific spectral parameters were also calculated for both the Etna samples and key sites on the Moon. In addition, in order to resemble the complex spectral response of the lunar pyroclastic deposits, we generated different mixtures using the spectra of the Etna samples intermixed with different amounts of olivine, orthopyroxene, and clinopyroxene endmembers spectra. Intriguing correlations between these mixtures and lunar spectral data were observed, even in study areas far from Apollo landing sites, indicating a broader range of similarities with the lunar pyroclastic materials.
Acknowledgement
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
1: Anand et al., 2012, A brief review of chemical and mineralogical resources on the Moon and likely initial in situ resource utilization (ISRU) applications. Planet. Space Sci. 74, 42–48.
2: Carey et al., 2022, METERON Analog-1: A Touch Remote. 73rd International Astronautical Congress (IAC), Paris, France, 18–22 September 2022
3: Ivanov, 2014, Volatiles in lunar regolith samples: A survey. Sol. Syst. Res. 48, 113–129.
4: Mateo et al., 2019, Lanzarote and Chinijo Islands Geopark:From Earth to Space. Springer International Publishing.
How to cite: Melchiori, G., Massironi, M., Pozzobon, R., Ferretti, P., and Calvari, S.: Unravelling similarities between Mount Etna's pyroclastic deposits and the Lunar counterparts., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17694, https://doi.org/10.5194/egusphere-egu25-17694, 2025.
