Structural development of magma-induced grabens and fracture systems: Geomorphological mapping of Cerberus Fossae, Mars

Graben and fracture systems are fundamental surface expressions of crustal extension and are widely used to infer subsurface magmatic and tectonic processes on rocky planetary bodies. In the Elysium Planitia region on Mars, the Cerberus Fossae system represents the geologically most recent example of tectono-magmatic activity. Cerberus Fossae is characterized by sharp, minimally degraded surface morphologies and is associated with young volcanic deposits. Moreover, the InSight mission detected marsquakes clustered near Cerberus Fossae in 2021-2022, suggesting ongoing crustal deformation potentially linked to the igneous system at depth (1). The lack of a systematic characterization of the spatial variability and morphology of the surface structures hinders relating them to the most recent magmatic and tectonic activity in the Elysium Planitia region on Mars.

We present a detailed geomorphological map and analysis of the regions within Cerberus Fossae that display diverse graben and fracture morphologies. Mapping is based on Context Camera (CTX) images from the Mars Reconnaissance Orbiter (MRO), High Resolution Imaging Science Experiment (HiRISE) and Colour and Stereo Surface Imaging System (CaSSIS) data (from the ExoMars mission) for detailed structural characterization, and Mars Orbiter Laser Altimeter (MOLA) and High Resolution Stereo Camera of Mars Express (HRSC) topographic data to constrain surface morphology and relief. Graben segment length, slope, width, depth, fault continuity, segmentation style, tip type, fracture density, and cross-cutting relationships are described and quantified, with particular attention to interactions between graben and their associated features with pre-existing structural fabrics.

The mapped geomorphological attributes express spatial patterns within the Cerberus Fossae system and suggest that differences in surface expression may reflect variations in subsurface magma emplacement, stress conditions, or host-rock mechanical properties. Cross-cutting relationships, fault geometries, and spatial relationships between fault traces, aligned fractures, and pit crater chains, provide constraints on the relative timing of deformation episodes, the fault propagation mechanisms, and suggest multiple stages of extension potentially associated with repeated magmatic intrusions. By combining high-resolution geomorphological mapping of Cerberus Fossae with comparative planetary and terrestrial perspectives, this study aims to refine interpretations of magma-assisted extension on Mars and improve our understanding of how subsurface magmatism is recorded in planetary surface morphology.

References:

• Stähler et al., 2022, Nature Astronomy