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Ascertain the mechanism driving resurfacing of Ganymede’s bright terrains

Ascertain the exact physical mechanism responsible for the resurfacing of Ganymede’s bright terrains, which are younger than the dark terrains, by identifying and characterizing the geological process(es) that produced the observed resurfacing signatures.

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Background

Ganymede’s surface exhibits distinct dark and bright terrains with different inferred ages. The dark terrain is dated to ~4.2 billion years, whereas the bright terrain appears to be much younger (~2 billion years), suggesting a resurfacing event.

Understanding the resurfacing mechanism is critical for interpreting the moon’s geologic history and for evaluating how surface features might record impacts, including potential dark matter signatures.

References

The darker regions that cover roughly one-third of Ganymede's surface have been dated to be on the order of 4.2 billion years old , while the brighter regions are thought to be the product of a resurfacing event in the more recent past, the exact mechanism of which is unknown.

— Dark wounds on icy moons: Ganymede's subsurface ocean as a dark matter detector (2508.00054 - DeRocco, 31 Jul 2025) in Section 2 (Ganymede)