The search for life on Mars involves the efforts of scientists from many different disciplines. An important aspect of that search is to study Martian sedimentary rocks for information about the planet’s environment when it is likely that the surface environment hosted abundant water and therefore more habitable, around three to four billion years ago. Now, new research published in the journal Geology shows evidence of an intense sandstorm that swept through Mars’ Gale crater over three billion years ago.
“Everybody knows that the wind blew on Mars. There was an atmosphere, so it must have moved, forming breezes and gusts, and so there must have been storms, too. But this is the first definitive evidence that we've found of such a sandstorm,” says Steven Banham , a planetary geologist at Imperial College London and lead author of the new study. “While it does not contribute to proving existence of life on Mars, it helps paint a rich picture of the ancient surface environment.”
The finding comes from the discovery of ripple structures by Banham and a team of scientists working with the Curiosity rover. These windblown sedimentary structures were formed in a desert environment, and resemble millimeter-thick “crinkly” laminations, says Banham. Wind ripple strata like this are rarely found on Earth and have never before been observed on Mars. They can only be formed when sustained winds move large amounts of loose sand. While most sedimentary structures preserved in desert rocks on Earth or Mars record longer-term trends from seasonal winds to several thousands of years, supercritical climbing wind ripples document evidence of storms that lasted only minutes to hours.
“The thing that absolutely amazes me, is you just think that on a Tuesday afternoon, sometime, maybe 3.6 billion or so years ago, there was a sandstorm that rolled into Gale crater,” says Banham. “It would be like one of those scenes in [the movie] Dune where there's a sandstorm happening and these ripple structures would be forming as a result. Then maybe the next day, the wind returns to normal, and it's just another sunny day in Gale crater. But that sandstorm happened, and we have the physical evidence for it here.”
The discovery involved a degree of luck. As the Curiosity rover navigates the Martian surface, a rotating team of scientists monitor its camera and other instruments. Banham and his colleagues, including Linda Kah from the University of Tennessee and Joel Davis from Imperial College London, noticed unusual features in a black and white panorama taken at the end of each drive. The team decided to target them with higher-resolution MASTCAM cameras. Upon closer inspection, they realized they were looking at unique ripples.
“This was very serendipitous. We weren't really looking for these deposits, and then lo and behold, we drove around the corner and found them,” says Banham. “We were lucky that we had just the right people on shift that recognized them.”
Direct evidence of the pressure and composition of the martian atmosphere over 3.5 billion years ago is hard to come by, but scientists know that the current martian atmosphere isn’t dense enough to move sand with wind on this scale. This research provides insight into the ancient conditions and suggests they were much higher and likely closer to that of Earth than they are currently.
“These deposits in themselves indicate that the atmosphere was denser at the time than it is now, to form these structures,” says Banham
Going forward, Banham hopes for similar serendipitous discoveries. One of the most exciting possibilities is to find rain impact marks. “People have been looking for those since Pathfinder and the MER rovers, and nobody's seen them,” says Banham, referring to the first Martian landings in the late 1990s and early 2000s. “It must have rained, as we’ve seen evidence of rivers and lake deposits. But we've not got that definitive evidence of rain until we see rain impacts. That would be magic if we found those.”
Citation: Banham, S., et al., 2026, An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars ; Geology: https://doi.org/10.1130/G54158.1
About the Geological Society of America
The Geological Society of America (GSA) is a global professional society with more than 18,000 members across over 100 countries. As a leading voice for the geosciences, GSA advances the understanding of Earth's dynamic processes and fosters collaboration among scientists, educators, and policymakers. GSA publishes Geology, the top-ranked “geology” journal, along with a diverse portfolio of scholarly journals, books, and conference proceedings—several of which rank among Amazon’s top 100 best-selling geology titles.
Geology
An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars