Some mud flows like lava on Mars, study says

This is the collapsed circular crater of a mud volcano in Azerbaijan, but it could be similar to so-called "mud volcanoes" on Mars.

(CNN)The surface of Mars is covered in intriguing features that suggest hints about the planet's past and the water that once existed on its surface.

New research has suggested that some lava-like formations on Mars are actually the product of mud that flowed like lava — not unlike traditional volcanoes like the ones we have on Earth.
The study published Monday in the journal Nature Geoscience.
    For years, Petr Brož, a researcher at the Institute of Geophysics of the Czech Academy of Sciences has been fascinated by detailed satellite images showing unique features on the Martian surface. Tens of thousands of kilometer-high steep cones are spread across Mars' northern hemisphere, and each cone bears a small crater on top.
      Brož wanted to know if they were formed by magma or mud. But in order to study this, Brož and his colleagues would have to establish how mud might behave on the Martian surface. But none of the researchers who he asked knew.
      Brož found a way to test how mud might react on Mars when he met Manish Patel, a senior lecturer in planetary sciences at The Open University who has also worked on multiple instruments for robotic space missions, including the European Space Agency's ExoMars rover that will launch in 2022.
      The Open University has the Mars Chamber, a low-pressure chamber that can reproduce Mars' atmospheric pressure and composition, as well as its surface temperature, Brož said in an email to CNN. Although it's still influenced by Earth's gravity, rather than that of Mars, it's the closest researchers can get to performing experiments on Mars.

        'Playing with mud'

        It's 3 feet in diameter and 5.9 feet long, and during Brož's experiments, things got a little messy. For a month, they averaged 10 hours a day in the lab, "playing with mud" to test what it might do on Mars.
        When the chamber was set to negative 4 degrees Fahrenheit, they poured the mud. Surprisingly, the mud did not freeze immediately. Instead, it formed an icy crust over the liquid mud inside. Liquid mud would then spill from cracks in the frozen crust, which then refreeze.
        Due to the simulated Martian conditions, such as the low atmospheric pressure, the water became unstable and boiled and evaporated. This caused the mud to eventually cool and freeze.
        The formations created by this process look similar to "ropy" lava flows in Hawaii and Iceland, where undulating surfaces form as the lava slowly cools.
        The researchers captured this image of mud flowing from a mud volcano in Azerbaijan.
        Compared to experiments with mud at Earth's atmospheric pressure, the mud didn't form an icy crust, expand or create lava shapes even as the temperature dropped.