NASA’s Perseverance rover recently uncovered thousands of intriguing, bleached rocks on Mars. These rocks are packed with kaolinite, a clay mineral that needs a lot of water to form. This discovery adds to the evidence that Mars was once a warmer, wetter planet, possibly with rainfall billions of years ago.
Adrian Broz, a postdoctoral researcher at Purdue University, explains that kaolinite typically forms when water interacts with rock over a long time, often in humid areas like rainforests on Earth. He suggests that if these rocks represent a rainfall-driven environment, it implies Mars might have been a habitable place for life in the past.
Briony Horgan, also from Purdue, further emphasizes the significance of these findings: “You need so much water that we think these could be evidence of an ancient warmer and wetter climate.” The Perseverance rover has found these kaolinite-rich rocks scattered across the Jezero crater, a region that likely held a lake long ago.
Since landing in 2021, Perseverance has been on a mission to find signs of past microbial life. Recently, it ventured up the crater’s walls to explore new areas. Scientists are keen to understand how Mars transformed from a wet environment to the cold, barren land we see today.
While researchers had previously identified areas on Mars with kaolinite from orbit, Perseverance’s close-up data allows direct analysis. Broz and his team compared the Martian rocks with kaolinite deposits found in Southern California and South Africa. The similarities strengthen their belief that these rocks formed through rainfall rather than volcanic activity.
Yet, one mystery remains: the origin of these rocks. Currently, there’s no clear nearby source. The closest potential birthplace is about 1.2 miles away, where past impacts created fractured rock that resembles kaolinite. Researchers also consider the possibility that ancient rivers might have transported these rocks into the crater.
As we explore Mars further, understanding its history becomes even more crucial. Recent studies show that water once flowed on Mars, raising questions about whether life could have ever existed there.
If you’d like to dive deeper into the research, check out the paper published in December 2025 in Nature Communications Earth & Environment. For further insights into Mars’s changing climate, you can visit NASA’s Mars Exploration page.
