Possible Organic Compounds Have Been Found In Martian Crater Rocks

Possible organic compounds were found in the rock of the crater on Mars – Astrobiology

Mars 2020 SHERLOC Instrument: A close-up of a technical model of SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals), one of the instruments onboard NASA’s Perseverance Mars rover. Credit: NASA/JPL-Caltech

A study published in Science analyzes several rocks found at the bottom of Jezero Crater on Mars, where the Perseverance rover landed in 2020, and reveals a significant interaction between the rocks and liquid water. These rocks also contain evidence consistent with the presence of organic compounds.

The existence of organic compounds (chemical compounds containing carbon-hydrogen bonds) is not direct evidence of life, since these compounds can be produced by non-biological processes. A future mission returning the samples to Earth would be required to determine this.

The study, led by researchers at Caltech, was conducted by an international team that included Imperial researchers.

Professor Mark Sephton of the Department of Earth Science & Engineering at Imperial is a member of the science team that participated in rover operations on Mars and considered the implications of the findings. He said, “I hope that one day these samples can be brought back to Earth so that we can look at the evidence for water and possible organic matter and examine whether the conditions for life were right in early Mars history.”

Flowing water

Perseverance has previously found organic compounds in the Jezero Delta. Deltas are fan-shaped geological formations formed at the intersection of a river and lake at the crater rim.

Mission scientists were particularly interested in the Jezero Delta because such formations can preserve microorganisms. Deltas form when a river carrying fine-grained sediments empties into a deeper, slower-flowing body of water. As the river water spreads, it slows down abruptly, depositing the sediments and trapping and preserving any microorganisms that may be present in the water.

However, the crater floor where the rover landed for safety reasons before traveling to the delta was more of a mystery. The researchers expected sedimentary rocks to be found in the bottom of the lake, because the water deposits sediment layer by layer. When the rover landed down there, however, some researchers were surprised to find igneous rock (cooled magma) with minerals in it on the crater floor, which recorded not only igneous processes but also significant contact with water.

These minerals, like carbonates and salts, need water to circulate in the igneous rocks, carving niches and depositing dissolved minerals in different areas like cavities and fissures. In some places, the data show evidence of organic matter within these potentially habitable niches.

Discovered by SHERLOC

The minerals and the organic compounds they may contain were discovered using SHERLOC or the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals instrument.

Mounted on the rover’s robotic arm, SHERLOC is equipped with a range of tools, including a Raman spectrometer that uses a specific type of fluorescence to look for organic compounds and also to see how they are distributed in a material to provide insights to give into their preservation at this place.

Bethany Ehlmann, co-author of the publication, professor of planetary sciences and associate director of the Keck Institute for Space Studies, said, “SHERLOC’s microscopic compositional imaging capabilities have really boosted our ability to decipher the temporal order of Mars’ past environments.”

As the rover rolled toward the delta, it took several samples of the water-altered igneous rock and stored them for a possible future sample-return mission. The samples would need to be returned to Earth and analyzed in laboratories with advanced instrumentation to definitively determine the presence and nature of organic matter and whether it has anything to do with life.


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