An article published in the journal “Nature Geoscience” reports a study on the mounds in Mawrth Vallis, a valley on the planet Mars considered very interesting for the traces of the ancient presence of liquid water. A team of researchers from the Open University and the Natural History Museum in London used data collected by various space probes to perform geomorphological and spectroscopic analyses of the mounds. Their conclusions are that they’re the remains that were formed by erosion by the retreat of the plateau in the Noachian period, between 4.1 and 3.7 billion years ago. For this reason, they believe that they constitute a sort of stratigraphic record of the changes in the presence of water in Mawrth Vallis.