NASA’s Perseverance rover recently collected four samples from an ancient river delta in the Red Planet’s Jezero Crater. This detection is made in an area where, in the distant past, sediments and salts were deposited in a lake under conditions in which life could have existed.
Jezero Crater, which is twenty-eight miles (45 kilometers) wide, is an ancient fan-shaped feature formed about 3.5 billion years ago at the convergence of a Martian river and lake.
Thomas Zurbuchen, NASA’s associate administrator for science in Washington, said: “We chose Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples, and now we know that we have sent the rover in the right location.”
“These first two science campaigns have yielded an incredible diversity of samples to bring back to Earth with the Mars Sample Return campaign.”
Perseverance Project Scientist Ken Farley of Caltech in Pasadena, California, said: “The delta, with its diverse sedimentary rocks, contrasts well with the igneous rocks, formed from the crystallization of magma, uncovered on the ground of the crater. This juxtaposition provides a rich understanding of the geological history after the formation of the crater and a diverse suite of samples. For example, we found a sandstone with grains and rock fragments created far from the Jezero crater and a mudstone with intriguing organic compounds”.
The rock is named Wildcat Ridge, which was formed billions of years ago when mud and fine sand settled in an evaporating saltwater lake. The Perseverance rover, on July 20, grazed some of the surfaces of Wildcat Ridge to analyze the area with the SHERLOC instrument.
SHERLOC analysis indicates that the samples exhibit a class of organic molecules that are spatially correlated with those of the sulfate minerals. Sulfate minerals found in sedimentary rock layers can provide important information about the aqueous environments in which they formed.
Farley said, “In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could have thrived. The fact that organic matter was found in sedimentary rock well known for preserving fossils of ancient life here on Earth is important. However, as capable as our instruments aboard Perseverance are, further conclusions about what the Wildcat Ridge sample contains will have to wait until it returns to Earth for an in-depth study as part of the agency’s Mars sample return campaign.
The geological diversity of the samples already carried to the rover is so good that the rover team is looking to deposit select tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its explorations of the delta.