Late-Stage Aqueous Activity at Gale Crater, Mars, Recorded by Sediment Fans Eroded From Aeolis Mons

Abstract

Gale crater, the landing site of NASA's Curiosity rover, and the mountain at its center, Aeolis Mons, hosts an extensive record of sedimentary rocks, which provide a window into the climate history of Mars. Curiosity has demonstrated that Gale hosted long-lived lakes early in its history, indicating warm, quiescent surface conditions, before transitioning into a period of heightened aridity. Recent investigations using orbital data have suggested that the surface of Mars was intermittently wet late in its history. However, an ongoing challenge is linking these orbital observations to on-ground investigations by rovers. Here we use combined orbital image and topographic data sets to investigate a series of sediment fans and related catchment regions within the wider Gale crater, and regional to Curiosity's exploration zone. These systems can be stratigraphically linked to the sedimentary rocks that Curiosity has investigated. We find that most of the sediment fans are likely alluvial fans, recording intermittent flow conditions, with deposition concentrated near the base of Aeolis Mons. The sediment fans are intermixed with landslide deposits and source canyons have been significantly backfilled. We find that these systems formed after regional geological units which Curiosity has shown to record periods of prolonged aridity. Our study demonstrates that intermittent surface water was likely to be present regionally with Gale crater during or after the exhumation of Aeolis Mons. Curiosity may be able to constrain the source and duration of these late-stage flow events as it ascends Aeolis Mons.