Hillside Gullies and Possible Glacial Landforms Associated with the Degradation of Highland Craters on Mars

Abstract

The discovery of recent water and ice related landforms on Mars has led to a new understanding of the planet. Hundreds of examples of gullies and tongue-shaped ridges have been found on hillsides in images from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). I conducted a thorough survey of these images and compiled a database of those containing gullies and tongue-shaped ridges, which may form as the result of flow of ice-rich materials. These features are found in similar mid-latitude bands. Crater counts on the ice flow features show estimated ages of the order 10⁶ y to 10⁷ y, similar to the timescale calculated for the last episode of high obliquity, when Models suggest ice deposition at these latitudes. Specific craters and various ice flow features were studied and compared in three regions: Newton Basin, Eastern Hellas, and Northern Elysium, leading to a model for crater degradation. Gullies, tongue ridges, debris aprons, and mantle deposits all may stem from recent cycles of ice deposition.