Earth’s Tectonic Engine Switched On | JQJO

Scientists have identified a chemical fingerprint in ancient rocks that marks the beginning of plate tectonics around two point seven billion years ago. The study examined over one thousand two hundred samples spanning nearly four billion years, revealing a lead isotopic signature that appears consistently in rocks older than two point seven to two point six three billion years but disappears in younger formations. This finding suggests a major shift in continental formation processes at that time. Researchers from Curtin University, including co‑author Chris Kirkland, emphasize that plate tectonics have fundamentally shaped Earth’s atmosphere, climate, and magnetic field. The discovery provides the clearest geological evidence yet for when the planet’s tectonic engine activated.