How Mars sediment flows changed as its air thinned ^{CEFR B2}

Researchers led by Georgia Tech report in Communications Earth & Environment a series of laboratory experiments that probe how atmospheric change altered sedimentary processes on Mars. The team, which includes members of the PLANETAS Lab and collaborators from other institutions, ran more than 70 tests in a Mars simulation chamber funded by NASA. In each test they flowed mixtures of water and sediment under a range of pressures and temperatures representative of Martian history.

The experiments demonstrate that atmospheric pressure strongly controls flow rheology and deposit morphology. Under higher pressures the water‑mud mixtures behaved in Earth‑like ways, suggesting some of Mars’s oldest sedimentary features could resemble terrestrial environments and may have been more habitable. After the Noachian, as the atmosphere thinned, boiling and freezing began to dominate, producing flows and deposits that differ markedly from Earth analogs. As Jacob Adler notes, at present low pressures mud can boil and levitate when warm or freeze and flow more like lava when cold.

The team also observed that small-scale climatic differences across varied topography can yield opposing flow behaviors simultaneously. They argue that matching laboratory morphologies with orbital and rover remote sensing can help time‑stamp paleoclimate episodes on Mars and improve interpretations of surface deposits.