Multi-Stage Ice Accumulation in Martian Mid-Latitude Craters During the Amazonian

The mid-latitudes of Mars harbor significant subsurface ice, representing one of the largest contemporary reservoirs of Martian water. However, the temporal evolution, extent, and drivers of Amazonian glaciation events remain insufficiently characterized. To elucidate this, we conducted comprehensive geomorphological mapping and numerical modeling, revealing a prominent southwestern orientation in ice-rich crater-fill deposits concentrated on northern mid-latitude crater walls and floors. Our detailed analysis identified multiple glaciation stages, notably an early intense phase followed by a subsequent, less intense phase, consistently exhibiting this southwestern depositional bias.

Using high-resolution orbital imagery (CTX, HiRISE) and digital elevation models, we systematically surveyed approximately 750 craters between 20° and 45°N. Depositional patterns align closely with modeled persistent thermal minima, driven by crater microclimates characterized by lower solar insolation and colder temperatures along southwestern walls. This is further supported by wind-driven ice redistribution analogous to terrestrial katabatic processes, suggesting a strong control by localized climatic conditions.

Chronological analyses utilizing crater size-frequency distributions (CSFD) indicate repeated glacial-interglacial cycles with declining intensity toward more recent periods (~98 Ma). Morphological distinctions within concentric ridges and depositional patterns further support these episodic glaciations. Our results demonstrates hemispheric consistency in cold-trap dynamics, suggesting global-scale climatic control modulated by orbital forcing, atmospheric water availability, and regional topographic influences.

Overall, this study enhances our understanding of Mars’ climatic evolution during the Amazonian, highlighting sustained obliquity-driven ice cycles and significant paleoclimatic shifts.