Indian rock yields oldest directly dated traces of microbial life
Researchers have found compelling evidence of microbial life in eastern India dating back at least 3.5 billion years ago, making it the oldest directly dated trace. The discovery, from a single carbon-bearing rock in the Singhbhum Craton, relies on converging chemical clues rather than fossils. Zircons extracted from the chert rock were dated to 3,497 million years, and the carbon's isotopic balance matched that of living cells, indicating biological origin. This finding pushes back the timeline for the emergence of life on Earth, suggesting life may have begun earlier than previously thought and could influence theories on evolution and habitability of worlds.
Key Points
- Traces of microbial life dating back at least 3.5 billion years ago have been found in a rock from India's Singhbhum Craton.
- The dating was achieved by analyzing zircons within the chert rock, yielding an age of 3,497 million years.
- Chemical clues, including the carbon isotope balance matching living cells, suggest a biological origin for the carbon traces.
- This discovery is significant as it pushes back the known timeline for life's emergence on Earth, impacting evolutionary hypotheses.
Exam Facts
- The discovery was made in the Singhbhum Craton in eastern India.
- The rock is dated to at least 3.5 billion years ago, with zircons indicating an age of 3,497 million years.
- The findings were published in the peer-reviewed Proceedings of the National Academy of Sciences.
- Trisrota Chaudhuri of the Geological Survey of India and Mark Harrison of the University of California, Los Angeles, are among the authors.
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