At the mouth of the Red Valley
The 120-mile-long Tinto Vallis is believed to have formed around 3.7 billion years ago, during the early history of Mars.
The European Space Agency’s (ESA) Mars Express took a high-resolution stereo image January 13 of the southeast corner of the Amenthes Planum region on Mars, near Palos Crater and the mouth of a well-known sinuous valley, Tinto Vallis.
At the bottom-center of the full-color image, and up close in the first perspective image, is a nearby shorter and wider valley that is fed by a number of tributaries before it joins the mouth of Tinto Vallis, as both empty into Palos Crater just off the bottom of the image.
The 120-mile-long (190 kilometers) Tinto Vallis is seen in the context image and is named after the famous Rio Tinto river in the Andalucía region of Spain. It is believed to have formed around 3.7 billion years ago, during the early history of Mars.
The network of shorter valleys shown in the first perspective image is thought to have formed through volcanic activity melting subsurface ice and liberating water to the martian surface via seeps and springs.
If underground water emerges to the surface from the side of a slope — a process that planetary geologists call “groundwater sapping” — it weakens the ground above it, causing it to collapse. Over time, this process may lead to the formation of steep-sided U-shaped valleys. Groundwater sapping is believed to be responsible for erosion seen in many of the valley networks on the Red Planet.
Another eye-catching feature is the relatively deep 20-mile-wide (35km) crater seen in the left-hand portion of the color, topographic, and 3-D images. Spectacular landslides along the crater’s walls can be seen and are particularly evident along the broken southern (left) rim.
This crater sits on top of at least three older craters, the largest of which is 60 miles (100km) wide and dominates the whole top left half of the 2-D and 3-D anaglyph images. The western rim of this crater continues beyond the image frame and can be more easily distinguished in the context image.
The floor of this 60-mile-wide (100km) crater is chaotic, with flat-topped geological features called mesas and their smaller siblings, buttes, littering the floor. These are probably the result of the removal of subsurface water ice leading to the collapse of weaker material around them, leaving these more-resistant, high-sided features behind. On Earth, the desert regions in Utah are home to many examples of these types of formation.
Toward the north (right) side of the 2-D images, several smaller craters display smooth, flat floors from infilling by sediments.
The darker regions to the far north and south, shown most clearly in the first color image, are covered in wind-transported basaltic sands.
The smooth low-lying region to the far right and shown in the second perspective image is a small trough that feeds into the broader lava field of Amenthes Planum. The trough has likely been modified by the outflow of material from the ancient lake that may have once existed in Palos Crater, the rim of which can only just be seen at the bottom of the color, topographic, and 3-D images. This smooth, channel-like feature brushes against the rim of a 20-mile-wide (30km) crater, and both have been covered with dark wind-blown materials.
With these recent images, Mars Express continues to show the similarities between regions on Mars with those on our home planet.