Public domain
Gullies and Bedrock in Nirgal Vallis
From the collection of NASA Image and Video Library. Free to download, adapt and use — no permission needed.
About this work
The gullies in this image are within the valley wall of an ancient channel-Nirgal Vallis-a testament to flowing water in Mars' ancient past. However, the formation of gullies are still the subject of much debate with respect to their formation: "wet" vs. "dry" or even "dry" with the aid of some lubricating fluid. Gullies most commonly form in the steep walls of simple craters. Gullies are common even in cold arctic deserts on Earth (e.g., the Haughton impact structure on Devon Island).
NASA Image and Video Library’s own descriptionCredit lineGullies and Bedrock in Nirgal Vallis. NASA/JPL, 2015-02-11. Public domain. ID: PIA19294.
