Mars

Geochemical Context for Hydrothermal Organic Molecules In Mars-analogue Samples From Earth

By Keith Cowing
Status Report
x-mol.net
January 16, 2025
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Geochemical Context for Hydrothermal Organic Molecules In Mars-analogue Samples From Earth
The Eridania basin of southern Mars is believed to have held a sea about 3.7 billion years ago, with seafloor deposits likely resulting from underwater hydrothermal activity.› Full image and caption Credit: NASA

Hydrothermal environments—where chemical interactions between heated water and rock take place—are of great interest for astrobiology as they may create habitable environments and preserve signs of life.

Several planetary bodies display evidence of hydrothermalism, including Mars, which has possessed various hydrothermal environments that could alter organic signals, complicating assessments of biogenicity and our understanding of the depositional environment and subsequent alteration processes.

Organic molecules from Earth-based hydrothermal systems serve as an analogue for what we might find on Mars and are typically made up of complex mixtures of in situ and transported molecules that have been altered by diverse mechanisms.

Improving our understanding of the processes that drive the preservation and circulation of organic molecules in Earth-based hydrothermal settings is crucial, as the sources and fates of these molecules in marine hydrothermal environments are different from those in subaerial (land-based) hydrothermal environments, even if many of the processes that govern the transport and alteration of this organic matter seem to be similar.

To understand the origin of organic molecules found in samples from another world, we must critically evaluate the processes that alter these molecules in terrestrial hydrothermal samples.

This diagram illustrates an interpretation for the origin of some deposits in the Eridania basin of southern Mars as resulting from seafloor hydrothermal activity more than 3 billion years ago. Credit: NASA

Geochemical context for hydrothermal organic molecules in Mars-analogue samples from Earth, Nature Astronomy via x-mol.net

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