Layers and Slope-Streaks within Valleys along the Highland-Lowland Boundary (context frame - MULTISPECTRUM; credits: Lunexit)

This image shows Slope Streaks and Layering on the walls of a valley along the border between the Martian Southern Highlands and Northern Lowlands (see the extra-detail mgnf. At the bottom of the valley and in the lower portion of the valley walls are many large dunes.

The Slope Streaks generally start at a point source and widen downslope as a single streak or branch into multiple streaks. Some of the Slope Streaks show evidence that downslope movement is being diverted around obstacles, such as large boulders. In particular, several of the Slope Streaks in this image appear to be diverting around individual dunes, with downslope movement occurring in the low troughs between the dunes. The darkest Slope Streaks are youngest and cross cut and lie on top of the older and lighter-toned Streaks.
The lighter-toned Streaks are believed to be dark streaks that are lightening with time as new dust is deposited on their surface.