Image Credit: NASA/JPL/ASU

Your eyes do not deceive you, this is a positive relief feature - a ridge. However, it does have a channel in its past. This type of feature is termed an inverted channel. One theory of how these features form is that rocky debris accumulates in channels of flowing water beneath glaciers. When the glacial ice is all removed the rocky channel bottom is left as a positive relief feature. On Earth such features are called eskers.

Please see the THEMIS Data Citation Note for details on crediting THEMIS images.