Geomorphological characterization and mapping of Martian rock glaciers

Introduction:

Viscous Flow Features (VFFs) on Mars are predominantly located at mid-to-high latitudes and share significant similarities with terrestrial glaciers. These features include high water-ice content, generally downslope flow patterns, heterogeneous deformation structures, and they are typically protected by a layer of debris [1]. Among these, Glacier-Like Forms (GLFs) resemble terrestrial valley or rock glaciers. Their surfaces are characterized by distinctive lineations, crevasses, and moraine-like ridges [2]. On the case of the Earth, rock glaciers are periglacial landforms resulting from the cohesive downslope flow of permafrost and frozen debris [3].

While these geomorphological features serve as critical indicators of the Martian paleoclimate fluctuations and represent potential water reservoirs for human missions, significant knowledge gaps remain. In particular, the mechanisms of their formation and their state of activity are not fully understood. In this context, detailed geomorphological mapping represents a fundamental initial step, as it allows the identification of surface units, morphologic relationships, and degradation patterns, providing the spatial and geological framework necessary to investigate the evolution, preservations state, and ice-related processes affecting Martian GLFs.

In this project, starting from the creation of a global database of GLFs on Mars, representative targets were selected for detailed geomorphological mapping and morphometric analyses. This multi-scale approach allows the investigation of surface processes and evolutionary trends across different glacial and periglacial environments on Mars.

The study aims to characterize the preservation state of GLFs, assess the potential preservation of subsurface ice beneath debris covers, and reconstruct the geomorphological and climatic framework controlling their formation and evolution on Mars.

Methodology:

To achieve these objectives, a multi-scale remote sensing approach was adopted, combining global surveys with detailed local investigations of selected targets. The analyses are based on data from:

• HiRISE: high-resolution images and DTMs of the surface [4];
• CaSSIS: colored and stereo high-resolution images and DTMs of the surface [5];
• CRISM: compositional and mineralogical information [6];
• SHARAD: subsurface stratigraphy and ice thickness [7].

Preliminary results:

The first step of this study involved the creation of a preliminary global database of potential Martian rock glaciers (Figure 1). This database allows us to i) analyze the latitudinal distribution of these features, ii) identify possible clustering of GLFs and iii) investigating their relationship with regional geomorphological and climatic settings.

Figure 1. Global distribution of identified Martian rock glaciers, based on database information.

Following this global assessment, we selected high-priority targets for detailed mapping. These were chosen based on the availability of high-resolution data and their potential to provide insights into favorable formation environments, local geology, and activity states (e.g., active vs. relict forms). Rock glaciers are not strictly related to craters. By identifying these landforms in non-crater areas, such as Mons, this work demonstrates a broader spatial distribution of these features.

Based on the initial database, a primary set of targets has been identified, and some geological maps have been produced, like Figure 2 [8]. The mapped crater is located in Noachis Terra (40°S, 4°E), a region characterized by extensive evidence of periglacial and glacial geomorphology. The crater itself hosts various periglacial landforms, in particular the equator-facing slope displays different GLFs. Furthermore, a prominent rock glacier, measuring 4.1 km in length and covering an area of ~10 km², is situated within this crater.

Figure 2. Detailed geological map of an impact crater (40°S, 4°E), hosting different GLFs and a rock glacier.

Conclusions:

Glacier-Like Forms (GLFs) can be indicative of the past climate changes on Mars preserved through their internal ice content and morphological state, to better constrain the formation and evolution of glacial features across the Red Planet (see also Bertoli et al. submitted to this EPSC). Furthermore, new high-interest targets highlight the need for further high-resolution data; indeed, we plan to acquire new CaSSIS data and stereo pairs, providing the detail required to characterize these areas.

Acknowledgements:

This work has been developed under the INAF-OAPD fellowship within the CaSSIS TGO e MARSIS MEX projects and the ASI-INAF agreement n. 2024- 40-HH.0.

References:

[1] Driver G., et al. (2024). Large glacier-like forms on Mars: Insights from crater morphologies and crater retention ages. Journal of Geophysical Research: Planets, 129. https://doi.org/10.1029/2023JE008207

[2] Hubbard B., et al. (2014). Glacier-like forms on Mars. The Cryosphere, 8. https://doi.org/10.5194/tc-8-2047-2014

[3] Meng T. M., et al. (2025). Effects of rock glacier dynamics on surface morphology and deformation. Journal of Geophysical Research: Earth Surface, 130. https://doi.org/10.1029/2024JF008106

[4] McEwen A. S., et al. (2007). Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE). Journal of Geophysical Research: Planets, 112. https://doi.org/10.1029/2005JE002605

[5] Thomas N., et al. (2017). The Colour and Stereo Surface Imaging System (CaSSIS) for the ExoMars Trace Gas Orbiter. Space Science Reviews, 212. https://doi.org/10.1007/s11214-017-0421-1

[6] Murchie S., et al. (2007). Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on Mars Reconnaissance Orbiter (MRO). Journal of Geophysical Research: Planets, 112. https://doi.org/10.1029/2006JE002682

[7] Seu R., et al. (2007). SHARAD sounding radar on the Mars Reconnaissance Orbiter. Journal of Geophysical Research: Planets, 112. https://doi.org/10.1029/2006JE002745

[8] Bertoli S., et al. (2025). Martian and Terrestrial Rock Glaciers: Paleoclimatic Insights, Permafrost Dynamics, and Implications for Astrobiology. Biennial European Astrobiology Conference (BEACON), abstract, Reykjavik (IS), 1-5/07/2025.