Scientists have long questioned whether the northern lowlands of Mars ever held vast reserves of water, and now a new study published by a team of international scientists has concluded that the Hypanis Valles may have once been a river system that flowed into a sea in Mars’ northern hemisphere.
It is known today that at one point in time, the climate of Mars was much wetter and warmer than it is today. But as its atmosphere gradually diminished between 4.2 and 3.7 billion years ago, Mars turned into the barren and cold place that we now know it to be. However, scientists have confirmed that lake and river beds do still exist on the planet, and now it appears that Hypanis Valles can also be added to this growing list of ancient river beds, as Phys.org reports.
The new study on this region of Mars used data collected from the 2001 Mars Odyssey probe and the Mars Reconnaissance Orbiter (MRO) to learn more about the planet’s sedimentary structure and morphology in the region of the Hypanis Valles.
Postdoctoral researcher Joel Davis from the Planetary Surface Group at the Natural History Museum was one of the co-authors of the new study and explained that billions of years ago Mars may have had a very similar water cycle to that found here on Earth, and that this would have lasted up until perhaps 3.7 billion years ago.
“Martian ocean means that Mars probably had a very Earth-like water cycle, with rivers, lakes, and now oceans, all of which probably interacted as part of a planet-wide system. We think this Earth-like hydrological cycle was active about 3.7 billion years ago, and started to shut down sometime after that. Our study is not definitive proof for an ocean, but these geological features are very hard to explain without one.”
While river deltas have previously been identified on Mars, these were only inside craters where the rivers flowed straight into lakes. For instance, while the Curiosity rover was studying the Gale Crater, it was discovered that this crater was at one time actually a lake. The evidence that determined this included clay minerals that were recovered from the bottom of Mount Sharp along with sedimentary deposits that could only have come from water slowly making its way into the crater.
Evidence at the Hypanis also shows there would have been enough water at one point in time that could have easily been an ocean. However, around 3.6 billion years ago this area would have dried up completely.
The Open University’s Dr. Peter Fawdon, who was the lead author of the new study, noted that in the future scientists would like to learn more about deltas like the one that would have existed along the Hypanis Valles.
“The research has significantly contributed to our understanding of the climate on early Mars, which we now know went from having a water cycle similar to that of Earth to being a cold, desert-like landscape in a relatively short period. We would like to gain a better understanding of how many of these fluvial deltas exist on Mars so that we can determine the position and size of its ancient seas.”
The new study that concluded that the Hypanis Valles on Mars once held an ancient river has been published in Earth and Planetary Science Letters and can be read on ScienceDirect.