Seasonal Flows in Valles Marineris

Recurring slope lineae (RSL) are seasonal flows on warm slopes, and are especially common in central and eastern Valles Marineris, as seen in this observation by NASA's Mars Reconnaissance Orbiter (MRO). This image covers a large area full of interesting features.

Here, the RSL are active on east-facing slopes, extending from bouldery terrain and terminating on fans. Perhaps the fans themselves built up over time from the seasonal flows. Part of the fans with abundant RSL are dark, while the downhill portion of the fans are bright. The role of water in RSL activity is a matter of active debate.

https://photojournal.jpl.nasa.gov/catalog/PIA21608