Scientists from the University of Kerala have identified terrestrial sites in Tamil Nadu and Chile that share geological and chemical features with Mars. The findings, supported by the Department of Science and Technology, use advanced laboratory analysis to understand how water once interacted with rock on Mars, information that could guide future missions searching for signs of ancient life.
Key facts
- Two minerals identified: melanterite in Neyveli, Tamil Nadu, and gypsum in the Atacama Desert (Chile) and Tiruchirappalli Badlands, Tamil Nadu
- Both are hydrous sulphates that show evidence of water-rock interactions
- Research led by Dr. Sajin Kumar K.S., Project Coordinator, DST-FIST at University of Kerala
- Analysis performed using laser Raman spectrometer, funded by DST-FIST (Department of Science and Technology Facility for Science and Technology)
- Findings published in the Journal of Geophysical Research: Planets
- Sites studied: Neyveli lignite substratum, Atacama Desert, and Tiruchirappalli Badlands
What are Martian analogue sites
As space agencies intensify exploration of Mars, scientists need terrestrial locations that mirror Martian conditions to test their understanding of the Red Planet. Orbital data and satellite imagery alone cannot fully reveal the mineralogy and geological history of Mars. By studying similar rock formations and minerals on Earth under controlled laboratory conditions, researchers can interpret what Martian rocks and minerals tell us about the planet’s past climate and habitability.
The minerals and their significance
Melanterite, found in the lignite mines of Neyveli, forms when sulphide minerals oxidize under wet, acidic, and oxidizing conditions. This mineral preserves evidence of temporary water presence and the chemical reactions that occur when water meets rock. On Mars, similar sulphate minerals suggest that water once flowed across the planet’s surface and interacted chemically with the ground.
Gypsum, identified in both the Atacama Desert and the Tiruchirappalli Badlands, forms through different processes. It records past aqueous environments and can trap and preserve biosignatures, the chemical or mineral traces left by living organisms, within its crystal structure. The presence of gypsum on Mars could indicate that ancient conditions were suitable for microbial life.
How the research was conducted
The research team used a laser Raman spectrometer, a high-precision instrument funded through DST-FIST, to identify the minerals. This tool measures how minerals scatter laser light in distinctive patterns, creating a spectral fingerprint unique to each mineral. By matching these patterns, researchers confirmed the presence of melanterite and gypsum and studied how they formed in their respective terrestrial environments.
The work demonstrates why Earth-based studies remain essential in planetary science. Orbital instruments on spacecraft can detect some minerals from orbit, but ground-truth data from terrestrial analogue sites provides the detailed understanding needed to interpret what the spacecraft data actually means.
Implications for Mars exploration
The identification of these analogue sites strengthens the scientific understanding of Mars’ past. If similar sulphate minerals exist on Mars, as orbital data suggests, they indicate that the planet once had liquid water and conditions potentially suitable for microbial life. These findings help planetary scientists identify regions on Mars most likely to preserve evidence of past habitability, guiding rovers and future human missions to search in the most promising locations.
The ability of gypsum and other sulphates to preserve biosignatures is particularly important. If life existed on early Mars, these minerals might have captured and locked away chemical or isotopic evidence of that life, waiting billions of years to be discovered by future explorers.
What happens next
The research team is now searching for additional analogue sites in extreme environments across the globe to expand their understanding of how primitive life might have existed in Martian conditions. They plan to use the same laser Raman facility to conduct astrobiological studies that could inform the design of instruments for future Mars missions and shape where those missions should focus their search for evidence of ancient life.