In very different environments, the same causes do not always have the same effects. One speaks of the planet Mars, our next-door neighbor, or exoplanets more exotic, it is something that one must always keep in mind. An international research team led by the Institute of geophysics of the Czech Academy of sciences and involving Susan Conway, a senior researcher of the CNRS at the laboratory of planetology and geodynamics (CNRS-university of Nantes-Angers university), comes to show that on the surface of Mars mud – mixture of water and rocks – has, frankly, tend to behave like the lava of a volcano at the surface of the Earth !

Mud, the surface of which was frozen by flowing under conditions of pressure and temperature similar to those of the planet Mars. The lobed shapes and troughs present in the crust are morphologies normally associated with the lava on Earth. © Brož et al/Nature Geoscience

researchers have devised a protocol of the experiment to simulate mud in the laboratory, on the one hand in conditions that are typically " land ", of the other part in the house of mars of the Open University (United Kingdom), where the conditions of pressure and temperature "the martian" have been recreated. The results are pretty amazing : the mud flowing in conditions similar to those that prevail at the surface of the red planet form of lava flows similar to the volcanic formations formations called Pahoehoe, hawaiian " river of satin ", on Earth. Lava flows smooth and shining, presenting either as a pile of cushions rounded, either as a succession of struts parallel giving it the appearance of a cluster of strings.

Trail of lava pahoehoe of the bay of Sullivan, island of Santiago, the Galapagos. © Jason Hollinger

How can this be ? It is, according to the scientists, because the conditions of temperature and pressure on mars the surface of the mud freezes on contact with the air, forming a stiff envelope, so that the heart of the casting remains liquid. The flow then progresses by rupture of this crust. Rupture, which allows the slurry to continue on its way until its surface freezes in its turn. It then draws a new lobe (or other sausage), and so on.

Adding to this that, when water seeps into the sub-soil, it may emerge again in some places in the form of mud, this new study, just published in the journal Nature Geoscience, calls on scientists to a thorough review of all of the reliefs martian up here interpreted as being of volcanic origin. To ask this question : does the result not instead of a mud slide ?