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Curiosity rover finds unusual mineral on Mars

Low-angle self-portrait of NASA's Curiosity Mars rover.

This low-angle self-portrait of NASA’s Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called “Buckskin”. The MAHLI camera on Curiosity’s robotic arm took multiple images on August 5, 2015, that were stitched together into this selfie. (Click to enlarge) Photo & Caption Credit: NASA/JPL-Caltech/MSSS

Researchers using data from NASA’s Curiosity Mars rover have found an unexpected mineral in a rock sample at Gale Crater. The discovery may change our understanding of how Mars evolved.

Curiosity has been studying sedimentary rocks in Gale crater since landing in August 2012. The rover collected powder from a rock at a location called “Buckskin” in July 2015.

Scientists analyzing sample data from the rover’s CheMin X-ray diffraction instrument detected significant amounts of a silica mineral called tridymite. This finding was a surprise to researchers as tridymite is usually associated with silicic volcanism, which occurs on Earth but was not thought to be present on Mars. The presence of this mineral suggests that the Red Planet may have once had explosive volcanoes.

The discovery was made by a team of researchers in the Astromaterials Research and Exploration Science (ARES) at NASA’s Johnson Space Center in Houston, Texas. A paper on the team’s findings was recently published in the Proceedings of the National Academy of Sciences.

“On Earth, tridymite is formed at high temperatures in an explosive process called silicic volcanism,” said Richard Morris, NASA planetary scientist at Johnson and lead author of the paper. “Mount St. Helens, the active volcano in Washington State, and the Satsuma-Iwojima volcano in Japan are examples of such volcanoes. The combination of high silica content and extremely high temperatures in the volcanoes creates tridymite. The tridymite was incorporated into ‘Lake Gale’ mudstone at Buckskin as sediment from erosion of silicic volcanic rocks.”

The authors of the paper looked for terrestrial evidence that tridymite could form at lower temperatures through geological  processes that do not imply silicic volcanism but could not find any.

“I always tell fellow planetary scientists to expect the unexpected on Mars,” said Doug Ming, ARES chief scientist at Johnson and co-author of the paper. “The discovery of tridymite was completely unexpected. This discovery now begs the question of whether Mars experienced a much more violent and explosive volcanic history during the early evolution of the planet than previously thought.”

Curiosity was launched from Cape Canaveral Air Force Station in Florida on Nov. 26, 2011, atop a United Launch Alliance Atlas V 541 variant booster. Since arriving on Mars, August 6, 2012, the rover has been studying the Martian environment to determine if the Red Planet is, or ever was, suitable for life.

Curiosity self-portrait

This self-portrait of NASA’s Curiosity Mars rover shows the vehicle at a drilled sample site called “Okoruso”, on the “Naukluft Plateau” of lower Mount Sharp. The scene combines multiple images taken with the rover’s Mars Hand Lens Imager (MAHLI) on May 11, 2016, during the 1,338th Martian day, or sol, of the rover’s work on Mars. Photo & Caption Credit: NASA/JPL-Caltech/MSSS


Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.

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