.png "Global Insight")
There is a patch of ground in Tamil Nadu that behaves, chemically at least, a little bit like Mars. Not the whole planet — no place on Earth can copy Mars. But two minerals found there, and in Chile's Atacama Desert, carry the same fingerprints of ancient water that scientists read in Martian rocks. Indian researchers have now mapped them in detail, and the result is a small but real addition to how we study the Red Planet without leaving Earth.
The work comes from the University of Kerala, where a geology team led by Dr Sajin Kumar K.S. used a laser Raman spectrometer to identify the minerals and confirm exactly what they are. Their findings were published as two papers in the Journal of Geophysical Research: Planets, and announced by India's Press Information Bureau on 16 October 2026.
What was actually found
The team identified two hydrous sulphate minerals — minerals that contain water in their crystal structure and record the history of water interacting with rock.
The first is melanterite, found at Neyveli in Tamil Nadu, in the lignite-rich belt around the town. Melanterite forms when sulphide minerals oxidise, and its presence is evidence of short-lived wet conditions — a brief window when water was active in the rock. That matters because sulphate formation on Mars is thought to have followed a similar path.
The second is gypsum, found in two places: the Tiruchirappalli Badlands, a semi-arid, paleoclimatic terrain in Tamil Nadu, and the Atacama Desert in Chile, one of the driest places on Earth. Gypsum records past aqueous activity over longer timescales, and it has another property that excites astrobiologists: it can preserve biosignatures — chemical traces of life — locked inside its mineral matrix.
Both minerals were identified by their spectral fingerprints. The laser Raman spectrometer, supported by the Department of Science and Technology's DST-FIST programme at the university, can detect the distinctive light-scattering signature of each mineral, confirming its identity without destroying the sample.
What is a Mars analogue site?
A Martian analogue site is a place on Earth whose geology, chemistry or environment resembles some specific aspect of Mars. The key word is specific. No Earth location reproduces Mars as a whole — the gravity, the atmosphere, the radiation and the temperatures are all different. What an analogue site offers is a controlled natural laboratory for one question at a time.
That is what makes the Tamil Nadu and Atacama sites useful. They are mineralogical analogues: the minerals there formed through the same kinds of water–rock interaction that shaped sulphate deposits on Mars. By studying how melanterite and gypsum formed, survived and changed on Earth, researchers can sharpen their reading of the same minerals when orbiters and rovers detect them on Mars.
It is the same logic behind better-known analogue sites — the Atacama has long been used to test Mars rovers and life-detection instruments, and volcanic fields in Hawaii and Iceland stand in for Martian lava flows. What is new here is the specific mineral pairing, and the fact that one of the sites sits in Tamil Nadu, in terrain shaped by ancient climates very different from today's.
Why sulphates matter for the search for ancient water
Water is the thread running through almost every question about Mars. The planet was once far wetter than it is today, and the minerals left behind by that water are the best record we have of when it flowed, how long it lasted, and whether it could ever have supported life.
Sulphates are particularly good record-keepers. They form when water interacts with rock and then evaporates or drains away, locking the chemistry of that water into the mineral. Melanterite captures the fleeting events — a short wet spell, a burst of oxidation. Gypsum captures the longer story, and can even trap organic material that might, one day, be recognised as a biosignature.
That is why the Kerala team's result is more than a mineralogical curiosity. If gypsum on Mars preserves biosignatures the way it does on Earth, then knowing exactly where and how it forms — and what its spectral fingerprint looks like — helps mission scientists decide where to look, and what their instruments should be tuned to find.
What this does not mean
Two things are worth saying plainly, because the headline version of this story invites both mistakes.
First, finding Mars-like minerals in Tamil Nadu does not mean life existed on Mars. It means the chemistry of ancient water on Mars can be studied through Earth rocks that went through similar processes. That is a tool for the search, not an answer to it.
Second, this is not the announcement of a new Indian Mars mission. The work is laboratory and field geology, published in a planetary-science journal. Its value is in the method — a better way to read Mars from Earth — and in the sites themselves, which the team now plans to extend by searching for rare analogue sites in extreme conditions around the world, to refine models of primitive life and support future planetary exploration.
Why a patch of Tamil Nadu belongs in planetary science
There is something quietly remarkable about the geography of this discovery. One of the driest deserts on Earth, in Chile, and a semi-arid badlands in Tamil Nadu now sit on the same scientific map as a planet 225 million kilometres away — connected not by distance, but by chemistry.
That is the point of analogue research. Mars is too far away to visit casually, and every rover landing costs billions. The more we can learn from rocks we can walk up to, pick up and put under a spectrometer, the smarter the expensive missions become. A mineral found at Neyveli may never leave Tamil Nadu, but the knowledge it carries is already on its way to Mars.
Read also: Voyager 1 Is Now More Than a Light-Day From Earth — What It Is Still Telling Us
Read also: The 7.6 km Train That Claims a 25-Year-Old World Record
Sources: Press Information Bureau, The Hindu