Unearthing Earth's Ancient Secrets: Rocks and Water Reveal Clues to Early Tectonics
Geochemical evidence obtained from Earth's oldest-known rocks, found in northern Canada, challenges previous theories about the early history of plate tectonics. The study reveals that there is no evidence of surface material recycling in the rocks dating back to 4 billion years ago, suggesting that subduction and plate tectonics may not have operated as they do today. However, a distinct shift in silicon and oxygen isotopes at 3.8 billion years ago indicates a possible change in Earth's geodynamics, potentially marking the onset of plate subduction. The findings shed new light on the early tectonic processes that shaped our planet.