NASA’s Curiosity Over Mineral Veins to be found on Mars

NASA’s Curiosity rover photographed a patchwork of crisscrossing rocky outcroppings on the Martian surface that appear to be two-tone mineral veins. The presence of the minerals adds further evidence that Mars had a watery past and could potentially harbor life.

The two-tone veins are at the site called “Garden City.” They appear as a network of ridges left standing above the now eroded-away bedrock in which they formed. Individual ridges range up to about 2.5 inches (6 centimeters) high and half that in width, and they bear both bright and dark material, according to NASA.

“Some of them look like ice-cream sandwiches: dark on both edges and white in the middle,” said Linda Kah, a Curiosity science-team member at the University of Tennessee, Knoxville. “These materials tell us about secondary fluids that were transported through the region after the host rock formed.”

Veins such as these forms where fluids move through cracked rock and deposit minerals in the fractures, often affecting the chemistry of the rock surrounding the fractures. Curiosity has found bright veins composed of calcium sulfate at several previous locations. The dark material preserved here presents an opportunity to learn more. Kah said, “At least two secondary fluids have left evidence here. We want to understand the chemistry of the different fluids that were here and the sequence of events. How have later fluids affected the host rock?”

Garden City is about 39 feet (12 meters) higher than the bottom edge of the “Pahrump Hills” outcrop of the bedrock forming the basal layer of Mount Sharp, at the center of Mars’ Gale Crater. The Curiosity mission spent about six months examining the first 33 feet (10 meters) of elevation at Pahrump Hills, climbing from the lower edge to higher sections three times to vertically profile the rock structures and chemistry, and to select the best targets for drilling.

NASA’s Mars Science Laboratory Project is using Curiosity to examine environments that offered favorable conditions for microbial life on ancient Mars, if the planet ever has hosted microbes, and the changes from those environments to drier conditions that have prevailed on Mars for more than three billion years.

After investigations in the Telegraph Peak area, the rover team plans to drive Curiosity through a valley called “Artist’s Drive” to reach higher layers. Engineers are meanwhile developing guidelines for best use of the rover’s drill, following detection of a transient short circuit last month while using the tool’s percussion action to shake rock powder into a sample-processing device. Drilling can use both rotary and percussion actions.

“We expect to use percussion as part of drilling in the future while we monitor whether shorts become more frequent,” said Steve Lee of NASA’s Jet Propulsion Laboratory, Pasadena, California. Lee became deputy project manager for the Mars Science Laboratory Project this month. He previously led the project’s Guidance, Navigation and Control Team from design through landing.