A global system of furrows on Ganymede indicative of their creation in a single impact event

TL;DR

This paper presents evidence that Ganymede's furrows form a global concentric structure likely caused by a massive impact, making it potentially the largest impact feature in the solar system, with implications for its geological history.

Contribution

It identifies a global multi-ring impact structure on Ganymede based on furrow distribution, suggesting a single impact event of approximately 150 km radius.

Findings

Furrows form a concentric global structure.

Deviations from concentricity are minimal.

Impact of ~150 km radius is consistent with observations.

Abstract

Furrows are a concentric system of tectonic troughs, and are the oldest recognizable surface feature on Ganymede. We analyzed the distribution of furrows utilizing Voyager and Galileo images and found that furrows over Ganymede's surface are part of a global concentric circular structure. If this multi-ring structure is impact origin, this is the largest impact structure identified so far in the solar system. Deviations of the shapes of the furrows from the concentricity are small everywhere, which implies that the relative location of the blocks of the dark terrains over the entire surface of Ganymede has not changed appreciably even during formation of the bright terrains. The estimate of the impactor size is difficult, but an 150km-radius impactor is consistent with the observed properties of furrows. The furrow-forming impact should have significant effects on the satellite's geological and internal evolution, which are expected to be confirmed by future explorations of Jupiter's icy moons, such as the JUICE (Jupiter Icy moon Explorer) or Europa Clipper mission.