THEMIS Image of the Day, April 24, 2019. This VIS image shows part of the rim of an unnamed crater in Terra Cimmeria. A group of channels dissect the rim near to upper left of the image. These channels are called gullies due to being on a steep slope rather than a flat river plain.
With careful examination, it is possible to see a boundary layer between the upper incised gully and a lower deposition region. The boundary marks a change in slope, the steep upper portion supports fast moving fluid that carves into the rim eroding materials.
The change to a flatter slope causes the fluid to slow down and as it slows the materials carried by the fluid a deposited.