Perseverance rover finds organic matter ‘treasure’ on Mars
A few of the recently collected samples include organic matter, indicating that Jezero Crater, which likely once held a lake and the delta that emptied into it, had potentially habitable environments 3.5 billion years ago.
“The rocks that we have been investigating on the delta have the highest concentration of organic matter that we have yet found on the mission,” said Ken Farley, Perseverance project scientist at the California Institute of Technology in Pasadena.
The rover’s mission, which began on the red planet 18 months ago, includes looking for signs of ancient microbial life. Perseverance is collecting rock samples that could have preserved these telltale biosignatures. Currently, the rover contains 12 rock samples.
Digging into the delta
The site of the delta makes Jezero Crater, which spans 28 miles (45 kilometers), of particularly high interest to NASA scientists. The fan-shaped geological feature, once present where a river converged with a lake, preserves layers of Martian history in sedimentary rock, which formed when particles fused together in this formerly water-filled environment.
The rover investigated the crater floor and found evidence of igneous, or volcanic, rock. During its second campaign to study the delta over the past five months, Perseverance has found rich sedimentary rock layers that add more to the story of Mars’ ancient climate and environment.
“The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks — formed from crystallization of magma — discovered on the crater floor,” Farley said.
“This juxtaposition provides us with a rich understanding of the geologic history after the crater formed and a diverse sample suite. For example, we found a sandstone that carries grains and rock fragments created far from Jezero Crater.”
The mission team nicknamed one of the rocks that Perseverance sampled as Wildcat Ridge. The rock likely formed when mud and sand settled in a saltwater lake as it evaporated billions of years ago. The rover scraped away at the surface of the rock and analyzed it with an instrument known as the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.
This rock-zapping laser functions as a fancy black light to uncover chemicals, minerals and organic matter, said Sunanda Sharma, SHERLOC scientist at NASA’s Jet Propulsion Laboratory in Pasadena.
The instrument’s analysis revealed that the organic minerals are likely aromatics, or stable molecules of carbon and hydrogen, which are connected to sulfates. Sulfate minerals, often found sandwiched within the layers of sedimentary rocks, preserve information about the watery environments they formed in.
Organic molecules are of interest on Mars because they represent the building blocks of life, such as carbon, hydrogen and oxygen, as well as nitrogen, phosphorous and sulfur. Not all organic molecules require life to form because some can be created through chemical processes.
“While the detection of this class of organics alone does not mean that life was definitively there, this set of observations does start to look like some things that we’ve seen here on Earth,” Sharma said….
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