Ancient Mars Rocks: Any Indication of Building Blocks of Life?


View of Yellowknife Bay Formation, with Drilling Sites
This mosaic of images from Curiosity’s Mast Camera (Mastcam) shows geological members of the Yellowknife Bay formation, and the sites where Curiosity drilled into the lowest-lying member, called Sheepbed, at targets “John Klein” and “Cumberland.” Unannotated version of image.

NASA’s Curiosity rover is providing vital insight about Mars’ past and current environments that will aid plans for future robotic and human missions.
In a little more than a year on the Red Planet, the mobile Mars Science Laboratory (MSL) has determined the age of a Martian rock, found evidence the planet could have sustained microbial life, taken the first readings of radiation on the surface, and shown how natural erosion could reveal the building blocks of life. Curiosity team members presented these results and more in six papers published online December 9, 2013 by Science Express and in talks at the Fall Meeting of the American Geophysical Union (AGU) in San Francisco.

The second rock Curiosity drilled for a sample on Mars, which scientists nicknamed “Cumberland,” is the first ever to have its mineralogy and age analyzed on its home planet. All previous extraterrestrial samples have needed to be brought back to Earth for such an analysis. A report by Kenneth Farley of the California Institute of Technology (Caltech) in Pasadena, and co-authors, estimates the age of Cumberland at 3.86 billion to 4.56 billion years old. This is in the range of earlier estimates for rocks in Gale Crater, where Curiosity is working.

Before they could measure rocks directly on Mars, scientists estimated their ages by counting and comparing the numbers of impact craters on various areas of the planet. The crater densities are correlated with ages based on comparisons with crater densities on the moon, which were tied to absolute dates after the Apollo lunar missions returned rocks to Earth.

As part of this science team, Doug Ming researches whether the Mars rocks have any indication of the building blocks of life.
Finding rocks with the youngest exposure age is important in the mission’s investigations of whether organic chemicals are preserved from ancient environments. Organic chemicals are building blocks for life, although they also can be produced without biological activity.
“We’re making progress on the path to determining whether there are Martian organics in there,” Doug Ming, of NASA’s Johnson Space Center in Houston said of the Cumberland rock sample. “We detect organics but can’t rule out that they might be brought along from Earth.” Curiosity detected higher amounts in Cumberland than it did in either test runs with Martian soil samples or analysis of empty sample cups. Increasing the amount of rock powder in the test cup increased the amount of organic content detected.

Ming is the lead author of a new report about a site called “Yellowknife Bay.” The team reported 10 months ago that the first rock Curiosity drilled there, nicknamed “John Klein,” yielded evidence that met the mission’s goal of identifying a Martian environment favorable for microbial life long ago. Yellowknife Bay’s clay-rich lakebed habitat offers the key chemical elements for life, plus water not too acidic or salty, and an energy source. The energy source is a type used by many rock-eating microbes on Earth: a mix of sulfur- and iron-containing minerals that are ready acceptors of electrons, and others that are ready electron donors, like the two poles of a battery.

Scientists within the Astromaterials Research and Exploration Science Directorate (ARES) of NASA Johnson Space Center, Houston, Texas who conducted research and were co-authors of the publications in the Science Express Dec 9, 2013 release are:
Paul Douglas Archer, Francis Cucinotta, John H. Jones, Douglas Ming, Richard V. Morris, Paul Niles, Elizabeth Rampe and Jacobs scientists: Cherie Achilles, Dorothy Oehler, Brad Sutter.

See the full NASA Press release, “NASA Rover Results Include First Age Measurement on Mars and Help for Human Exploration”,   NASA Release 13-366 on Dec. 9, 2013.