The importance of lake breach floods for valley incision on early Mars

Early Mars had an active hydrologic cycle, with flowing liquid water that carved river valleys and filled lake basins. Over 200 of these basins accumulated enough water to overflow, breaching the surrounding terrain and causing catastrophic floods that carved deep outlet canyons. While previous studies have highlighted the local impact of these lake breach floods in rapidly creating large valleys, most martian valley systems have been viewed as the result of prolonged fluvial erosion tied to a more widespread hydrologic cycle. In this study, we reveal the global significance of lake breach floods, showing that they were responsible for eroding at least 24% of the volume of incised valleys on early Mars, despite accounting for only about 3% of the total valley length. We conclude that lake breach floods played a major role in shaping martian valleys and influenced the overall landscape evolution of the planet’s cratered highlands. These findings underscore the importance of considering lake breach floods when reconstructing the formation of martian valley systems.

Goude, Morgan, et al. (2022) Nature