Department of Earth Sciences

The HRSC image shows a section of Mamers Valles, a huge canyon and channel system in the northern hemisphere. The valley system stretches roughly 1,000 kilometers across the Martian dichotomy, from the ancient highlands of Arabia Terra to the lower plains near Deuteronilus Mensae (see context map). In its middle sections, the valley is about 25 kilometers wide and as much as 1.2 kilometers deep. The surrounding area is known as so called ”fretted terrain”, a region characterized by numerous deep and very wide labyrinth like valleys, flat-topped mesas, steep cliffs and glacier-like deposits (see annotated image). The region dates back to the Late Noachian period, around 3.8 billion years ago, when Mars was transitioning from a wetter, more geologically active world into the colder planet we see now. The name “Mamers” comes from the Oscan language, an ancient Italic language of pre-Roman Italy, where “Mamers” meant Mars. The feature received its official name in 1976. Mamers Valles is smaller than the famous Valles Marineris — the “Grand Canyon of Mars”.

One reason planetary scientists find Mamers Valles interesting is that it may preserve evidence of multiple geological processes like ancient flowing water, lava flows and even glacial or ice-related activity and therefore provides insight into how ice and erosion shaped the Martian surface over billions of years. The valley floor contains long linear ridges and textures that resemble debris-covered glaciers on Earth. Many researchers think these features formed when ice slowly flowed through the canyon and became coated with rock and dust. Ice is also present adjacent to steep cliffs and hillsides, where rocky debris from slopes covers and protects the ice from sublimation into the atmosphere (see annotated image).

Mars has a very thin atmosphere – only about 1% as dense as Earth’s. Still, atmospheric phenomena like dust devils are widely observed on Mars. During just one orbit, HRSC captured numerous active dust devils (see small boxes in annotated image), which are short-lived, localized whirlwinds – much smaller than large-scale dust storms. Dust devils typically form in the afternoon, when the heated Martian surface warms the air above it, causing the air to rise. The rising hot air creates a vertical vortex (whirlwind) that lifts dust and sand into the atmosphere. Through this process dust devils play a significant role in stirring up and distributing dust across the Martian surface.

In the HRSC images, dust devils appear as small bright spots with a trailing pinkish “shadow”. This shadow effect is caused by the dust devil’s fast motion during image capture. The HRSC imaging channels cover the same surface area at slightly different times: the nadir channel views vertically downward, while some channels view slightly forward and others slightly backward. This makes it possible to detect changes in the dust devil’s position and analyze its direction and speed.

 On Mars, dust devils can reach speeds of up to 45 m/s and heights of up to 8 kilometers, though they are usually less than 100 meters wide. They are commonly found in broad plains and also here in Mamers Valles – similar to their counterparts on Earth, which occur in dry desert landscapes. Despite the differences in atmospheric conditions, Martian and terrestrial dust devils share many similarities. However, those on Mars are often much larger, mainly due to large temperature differences caused by intense daytime heating.

Neighboring areas are shown in a 2008 release from orbit 3304 (Crater in Mamers Valles) and in a 2019 release from orbit 17913 (Deuteronilus Mensae).