Glacial landforms in Deuteronilus Mensae on Mars
Deuteronilus Mensae is situated at the transition from the rugged and cratered southern highlands to the smooth northern lowlands, referred to as the Martian hemispheric dichotomy. The landscape here at the dichotomy boundary was deeply eroded by fluvial, mass wasting and in particular ice related processes. Fretting and dissection of the ancient highland material resulted in the formation of isolated mesas with plateau-like surfaces, constituting eroded remnants of the plains that once extended further to the north.
During the past, the region experienced extensive glaciation and is therefore characterized by landforms that resulted from multiple glacial epochs. All of the low lying terrain is covered by smooth deposits, partly showing flow patterns that indicate slow downhill movement of the material. The viscous flow features surrounding the plateaus resemble rock glaciers and debris-covered glaciers found in cold-climate areas on Earth, and most likely consist of ice mixed with mass-wasted debris.
Data analysis of the Shallow Radar (SHARAD) instrument onboard Mars Reconnaissance Orbiter indicate that most of the glacier-like landforms in Deuteronilus Mensae contain a high amount of 80-90% of pure water ice. The widespread glacier-like features may represent the preserved remnants of a regional ice sheet, which once could have covered the plateaus and plains. Sublimation in the course of climate change could then have led to down wasting of the ice sheet, exposing and eroding the plateau scarps. Later, annual atmospheric ice and dust deposits form a thick mantling layer. The “ribbed texture” of the smooth plains in the northern part of the image can be explained with downhill creep, leading to fractured ridge and furrow patterns.