In the South Polar Region of Mars' Promethei Lingula there is an unusual cone shaped hill, measuring about 20-30 meters high. The white streaks are areas where carbon dioxide ice has not yet thawed. The unusual shape of this hill can likely be attributed to large scale erosion. Scientists still aren't sure why the area wasn't eroded evenly, but as they study more images of features like this they will gain a better understanding of the environment that created them.
|Click to see HiRISE's original high resolution version. [See HiRISE caption]|
One possible way this cone-shaped hill was created would have occurred long ago, when it once rained on Mars. A meteor could have hit the area, creating a crater, which would eventually developed a central uplift. After millions of years of rainfall the central uplift would have been smoothed out to what we see above, as the water flowed down its slopes. Over millions of years the distinguishing characteristics of the surrounding crater would have been washed away by the rain, blending it into the regional terrain. That's just a theory and an example of the fact that we may never know what caused this feature on Mars to develop.