Liquid water is essential for life as we know it to exist, so it's always exciting when any reports about water on Mars are released. The latest findings include evidence that water existed on Mars a mere 200,000 years ago; quite recent on the geological timescale. The results of the study come from lead author Andreas Johnsson and a team from the University of Gothenburg and were published in the journal ICARUS.
In the mid-latitudes in Mars’ southern hemisphere, the researchers discovered a very young crater. Inside, they found gullies and deposits that appear to be created by the recent flow of liquid water. Debris flow deposits form when the sediment (which is composed of soil, rock, clay, and water) that is on a slope becomes oversaturated and begins to slide down as one unit, kind of like a landslide. The team analyzed those Martian features through photography while conducting field studies on Earth. Their studies "Our fieldwork on Svalbard confirmed our interpretation of the Martian deposits. What surprised us was that the crater in which these debris flows have formed is so young," Johnsson said.
Mars is believed to have undergone an ice age 2.1 million-400,000 years ago, so it was a surprise that the researchers’ analysis of the crater put it at 200,000 years old. This is long after water-related activity was believed to have ended in that region, so it is unlikely that the evidence of water can be explained away that easily.
The crater overlaps with an older, larger rampart crater’s ejecta, which have distinct fluid-like features, likely due to saturated soil at the point of impact. "My first thought was that the water that formed these debris flows had come from preserved ice within the rampart ejecta” Johnsson explained. “But when we looked more closely, we didn't find any structures such as faults or fractures in the crater that could have acted as conduits for the meltwater. It is more likely that the water has come from melting snow packs, when the conditions were favorable for snow formation. This is possible, since the orbital axis of Mars was more tilted in the past than it is today.”