Caltech Researchers Challenge Global Interpretation of 2-Billion-Year-Old Earth Clue
Caltech researchers, led by Nivedita Thiagarajan, have published a new study in Geology questioning the long-held interpretation of a significant carbon-isotope signal found in 2-billion-year-old rocks from the Zaonega Formation in Karelia, Russia. This signal, along with a similar one from the Francevillian Basin in Gabon, has traditionally been seen as evidence of a worldwide environmental change during Earth's early oxygenation. The research team, including John Eiler and Aivo Lepland, analyzed gases trapped in microscopic pockets within these rocks. Their findings suggest that the unusual carbon-isotope signal at the Zaonega site can be attributed to local phenomena occurring within a several-hundred-square-kilometer sedimentary basin, rather than a global event. They propose that magma intrusions heated marine sediments, generating hydrocarbons like methane and propane. Microbes near the seafloor then consumed this methane, producing biomass with a light carbon isotope signature, which could explain t...
