Upgrade helps NASA’s Curiosity rover examine mineral veins on Mars
Researchers working with NASA’s Curiosity Mars rover mission recently used an improved set of data analysis tools to gain a better understanding of the most chemically diverse set of mineral veins that the rover has examined on the Red Planet to date. The bright and dark mineral veins at a site called “Garden City” were examined by Curiosity in March 2015. Some of the veins protrude as high as two finger widths above the eroding bedrock that they formed in.
The diversity of minerals in the crisscrossing veins indicates that there were multiple periods of water moving through fractures in the bedrock when it was buried. The water carried different dissolved substances during different wet periods. Telltale traces were left behind when conditions dried. Researchers are now studying these clues for insight into how the ancient environment of Mars changed over time.
“These fluids could be from different sources at different times,” said Diana Blaney, a Curiosity science team member at NASA’s Jet Propulsion Laboratory, Pasadena, California. “We see crosscutting veins with such diverse chemistry at this localized site. This could be the result of distinct fluids migrating through from a distance, carrying chemical signatures from where they’d been.”
Scientists used Curiosity’s laser-firing Chemistry and Camera instrument (ChemCam) to record the spectra of spark created by zapping 17 targets at Garden City with the laser. The diverse chemistry detected at the site includes calcium sulfate in some veins and magnesium sulfate in others. Other veins were found to contain fluorine or varying levels of iron.
The detailed analysis of Curiosity’s observations of the veins was made possible by an extensive upgrade to the ChemCam data-analysis tool-kit. The ChemCam team has more than tripled the number of Earth-rock geochemical samples examined with a test version of ChemCam, bringing the total to 350. This enabled improved data interpretation, making ChemCam sensitive to a wider range of possible composition of Mars rocks.
Blaney said, “The chemistry at Garden City would have been very enigmatic if we didn’t have this recalibration.”
On Wednesday, November 11, Blaney presented findings from Curiosity’s examination of Garden City at the annual meeting of the American Astronomical Society’s Division for Planetary Science, in National Harbor Maryland.
The Garden City site is located uphill from a mudstone outcrop called “Pahrump Hills” where Curiosity spent six months investigating after reaching the base of Mount Sharp in 2014. Curiosity has discovered evidence that the lower layers of Mount Sharp were deposited in lakes and rivers. The wet conditions indicated by the Garden City veins existed in later eras after the mud deposited in lakes had hardened into rock and cracked. ChemCham has enabled scientists to better understand the complex geological and chemical history of this region. Since leaving Garden City, Curiosity has climbed to higher, younger regions of Mount Sharp.
The image above covers an area roughly 2 feet (60 centimeters) across; the annotations point to the types of vein material: 1) thin, dark-toned fracture filling material; 2) thick, dark-toned vein material in large fractures; 3) light-toned vein material, which was deposited last.
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.