Oldest Dated Evidence of Ancient Microbial Life Found in Indian Rock

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Key takeaways

Scientists discovered 3.5 billion years old evidence of ancient microbial life in carbon-bearing chert rock from Bhitardari in the Singhbhum Craton.
Dating of 4 out of 8 zircon crystals pinpointed the rock age to approximately 3,497 million years.
The Singhbhum Craton, spanning Jharkhand and Odisha, holds Earth's crust records dating back more than 4 billion years.
Published in PNAS, this discovery offers one of the world's oldest directly dated biosignature records to study early life and space habitability.

A research paper published in the Proceedings of the National Academy of Sciences (PNAS) shows evidence of microbial life from 3.5 billion years ago in eastern India.
Researchers identified these organic traces inside ancient rock samples collected from the Singhbhum Craton.

Scientists collected the carbon-rich chert rock sample from Bhitardari, a site inside the Singhbhum Craton that extends across Jharkhand and Odisha.
Chert is a dense, silica-heavy rock that can protect organic matter from breaking down over billions of years.
The Singhbhum Craton represents one of the oldest landmasses in India, with crust formations dating back more than 4 billion years.

Testing 8 zircon crystals embedded in the rock revealed that 4 of them were approximately 3,497 million years old.
Chemical testing revealed carbon isotope ratios that match the exact signatures produced when living organisms fix carbon.
Detailed organic analysis confirmed that the carbon comes from decayed ancient life rather than modern chemical pollution.

This discovery stands among the world's oldest directly dated biosignatures of microbial life established through chemical and geological tests.
The findings help scientists understand early biological growth on Earth and aid in searching for life on other habitable planets.