Scientist have known that Mars, at some point in its life, had water on its surface. Scientists have now found the first evidence of rivers in long-term action preserved in the rock of an exposed cliff-face on the Red Planet. The team says that rivers continuously shifted in their gullies, creating sandbanks similar to the Rhine or rivers found in Northern Italy.
Using high-resolution orbital imagery of the Martian surface, a team of scientists has discovered the stratigraphic product of multiple extensive fluvial channel belts in an exposed vertical section at a location called Izola Mensa in the northwestern rim of the Hellas Basin. The rocky cliff is 200-meters high and provides evidence of an ancient watery landscape.
The cliff has sedimentary rocks that are 3.7 billion years old and performed by rivers that were likely active for over 100,000 years of Martian history. Scientists say that the extremely high-resolution imagery allows them to “read” the rocks as if they were standing close to the cliff. The team notes that they don’t have the ability to climb and look at finer-scale details, but the similarities to sedimentary rocks on Earth leaves “very little to the imagination.”
The oblique layers suggest ancient rivers with channel depths several meters deep. The team believes there was a large lake in the Martian southern hemisphere. In the Hellas impact crater, which is one of the most significant impact craters in the solar system, landforms preserved on the surface give evidence of a network of ancient rivers, deltas, and outflow channels with mineral evidence suggesting the region once hosted a huge lake.
The team says that they were lucky that the rock face was slanted just enough to allow the satellite to photograph it from precisely the right point. Evidence suggests prolonged water discharges that are most consistent with a precipitation-driven hydrological cycle. The team believes the study demonstrates sustained river deposition on Mars 3.7 billion years ago.