Curiosity rover uncovers billion-year-old Martian sandstorm frozen in rock

Inside Gale Crater on Mars, tucked among the ordinary-looking rock outcrops that Curiosity has been cataloging for years, sits a record of a single afternoon billions of years ago. What appeared at first to be just another fractured slab of sedimentary stone turned out to be something far more specific: the physical imprint of a sandstorm that lasted only a few hours, preserved in stone ever since.

The rover photographed these rocks in December 2024 while exploring a region called Jawbone Canyon. Scientists examining the panoramic images noticed something unusual in the texture—delicate, ripple-like layers stacked one atop another in a pattern that looked familiar. They recognized it as climbing wind ripple strata, a sedimentary structure that forms when fast-moving sand ripples keep advancing forward while fresh sand deposits accumulate on top of them. This was the first time such formations had been identified on Mars. The discovery appeared in March 2026 in the journal Geology, with the study titled "An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars."

What makes this find remarkable is its brevity. Most Martian rock layers tell stories measured in centuries or longer—slow accumulations of dust and sediment that record environmental conditions over vast stretches of time. These ripples, by contrast, appear to capture something that unfolded in hours. The study reports evidence of both brief wind gusts lasting only minutes and a larger storm system that probably continued for several hours. Once buried beneath later sediments, the ripples gradually hardened into rock, allowing the storm's signature to survive for roughly 3.5 billion years.

Steven Banham, a planetary geologist at Imperial College London and lead author of the study, described the discovery as the first definitive evidence of an ancient Martian sandstorm. "Everybody knows that the wind blew on Mars," he said. "But this is the first definitive evidence that we've found of such a sandstorm." The finding carries weight because the sedimentary structures themselves tell a story about Mars' past atmosphere. Modern Mars has an atmosphere so thin it cannot generate the sustained, powerful winds needed to create these distinctive ripple patterns. Their presence in the rock record suggests that around 3.5 billion years ago, Mars possessed a much denser atmosphere capable of producing stronger and more sustained winds than anything the planet experiences today.

The discovery was not something the team had been actively hunting for. Researchers first noticed the unusual textures while reviewing Curiosity's images from Jawbone Canyon. Only after closer inspection did they realize the millimetre-scale laminations matched rare sedimentary structures previously documented on Earth. The rover had simply passed the outcrop while conducting its regular survey work, and specialists recognized something extraordinary in what might otherwise have gone unnoticed.

This sandstorm evidence fits into a larger picture scientists have been assembling about Mars' early climate. Researchers already have strong evidence for rivers and lakes that once flowed inside Gale Crater, pointing to a warmer and wetter environment billions of years ago. The newly identified storm record adds another layer to that understanding—a snapshot of active weather in a world very different from the cold, dry planet Mars has become. The team now hopes future rover observations might reveal other preserved weather events, particularly raindrop impact marks in Martian rocks, something scientists have searched for since the earliest rover missions but have yet to find. For now, a sandstorm that lasted only a few hours remains locked inside Martian stone, a message from deep time waiting to be read.