Textured terrain

This image covers part of the region surrounding Pavonis Mons, one of the Tharsis volcanoes. The ridges running from lower left to upper right on the image are the margin of an areole that surrounds the volcano. How this feature forms in not understood. The margins of lava flows can be seen to the north of the areole. The surface of the areole has been eroded by the wind, indicating that it is not a strongly cemented material - and likely not a lava flow. Some of the material being stripped from the areole has been formed into dunes along the outermost margin of the areole.