The origin of life on Earth holds many mysteries for scientists of all disciplines. In the 1960s, professors and students at Harvard published short papers describing their findings of trace fossils from early microbes in some of the Earth’s oldest Precambrian rocks, 1 to 4 billion years old. At the time, the biological revolution was still a decade away. In earth science, plate tectonics did not yet provide the framework for interpreting how continents were built or how their sedimentary features had been formed. Dating of rocks was just being developed, and many of the Precambrian deposits studied at this...

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