Mars' Bleached Rocks Suggest Tropical Oasis Existed in the Past

Strangely bleached rocks found on Mars suggest that the Red Planet may have once been a tropical oasis. According to a study published on December 1 in the journal Communications Earth & Environment, NASA's Perseverance rover discovered peculiar light-colored rocks, identified as kaolinite, an aluminum-rich type of clay.

Soil scientist Adrian Broz from Purdue University stated that on Earth, kaolinite forms under warm, humid conditions, typically seen in tropical rainforests. The presence of kaolinite on Mars indicates that there was likely much more water on the planet in the past than there is today.

Broz and his team compared the structure of the Martian kaolinite with terrestrial samples from South Africa and San Diego, finding them strikingly similar. Satellite images show larger kaolinite deposits elsewhere on Mars, though Perseverance has not yet explored those areas.

Co-author Briony Horgan emphasized that these small rocks represent our only on-the-ground evidence of past conditions. This discovery supports the hypothesis that Mars was a wetter oasis millions of years ago, although the timeline of when it dried up remains debated.

Leading theories suggest that the planet lost its water between three and four billion years ago due to a weakening magnetic field that allowed solar winds to strip away the atmosphere. The researchers believe studying these ancient clays could provide more insight into Mars' water loss history.