Study Suggests Plate Tectonics Began Over 3 Billion Years Ago

A study published on March 19 in the journal Science presents evidence that Earth's crust may have started shifting as early as 3.48 billion years ago. Researchers, led by paleomagnetic geologist Roger Fu from Harvard University, analyzed ancient rock samples from the Pilbara region in Western Australia. They collected over 900 sediment cores by drilling at more than 100 sites, with samples dating from 30 million to 3.48 billion years old. Analysis of magnetite grains in these rocks revealed that part of the Pilbara formation moved toward a pole at a rate of about 18.5 inches per year and rotated clockwise by over 90 degrees during its early history, later slowing down. This movement, contrasted with stationary ancient rock in South Africa, indicates the presence of independent tectonic plates and a potential plate boundary. The study also found the earliest known evidence of a geomagnetic reversal around 3.46 billion years ago. According to experts like Michael Brown, an emeritus geologist at the University of Maryland, these findings suggest Earth's geological processes were active billions of years ago, similar to today. Plate tectonics is considered crucial for Earth's habitability, possibly initiating the carbon cycle that supports life. The research involved contributions from Alec Brenner, now at Yale University, and highlights the role of tectonic activity in shaping the planet's atmosphere and climate.