NASA’s Mars Rover Curiosity found a Martian rock containing crystals of elemental sulfur, which means it’s pure sulfur. In the past, in the same area, the Gediz Vallis channel’s area, the presence of sulfur in various compounds was detected but it’s the first time that it was detected in its pure form. It’s such an anomaly that its discovery was compared to that of an oasis in the desert. A field with stones made of pure sulfur shouldn’t exist on Mars, and scientists following Curiosity’s exploration of Mount Sharp, at the center of Gale Crater, will have more work to do to explain its formation.
In August 2023, the Mars Rover Curiosity began a new stage of the long journey, which began with its landing on Mars on August 6, 2012, when it reached Gediz Vallis. It’s a ridge created by the accumulation of debris left on Mount Sharp by an ancient presence of water. It took various attempts to reach this ridge because some sharp rocks and steep slopes prevented Curiosity from entering it.
After the ridge, at the end of March 2024, the Mars Rover Curiosity reached the Gediz Vallis channel, above the ridge. It’s a place considered interesting from a geological point of view because scientists believe it may offer new information on how and where water flowed down Mount Sharp. The area was chosen among Curiosity’s targets thanks to the images captured from orbit precisely to conduct this type of research. It wasn’t certain that the erosion was caused by water when Mars was young and Gale Crater was a lake but the features made it unlikely that wind alone had carved out the channel.
During its journey in the Gediz Vallis, the Mars Rover Curiosity detected several compounds that contained sulfur but the surprise came on May 30, when the scientists saw a rock broken by Curiosity passing over it which contained stones made of elemental sulfur, therefore pure sulfur. This is an odorless form, as the rotten egg smell commonly associated with sulfur is actually generated by hydrogen sulfide.
Sulfur shouldn’t be present in that purity, as it’s normally present in compounds and the elemental form is only formed under very few conditions, so its discovery is intriguing to scientists. In short, it was an accidental and decidedly fortunate discovery. It adds another surprise to the exploration of Mount Sharp on Mars.
