Crater Gullies

This VIS image shows part of the rim of an unnamed crater in Terra Sirenum. A group of channels dissect the rim in the center of the image. These channels are called gullies due to being on a steep slope rather than a flat river plain. In some images 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 are deposited.