The study presents the earliest direct evidence that plate tectonics was active on Earth about 3.5 billion years ago during the Archean Eon, reshaping our view of early Earth and life.

Paleomagnetic data from the Barberton Greenstone Belt in South Africa show near-stationary behavior for the same period, supporting a model of a lithosphere segmented into moving blocks rather than a single global shell.

Findings from the Pilbara region reveal a latitudinal shift from 53 degrees to 77 degrees and a clockwise rotation exceeding 90 degrees over tens of millions of years, indicating significant early plate motion.

The study was led by Harvard University’s Roger Fu and published in Science on March 19, with corroboration from Yale and other researchers.

The researchers argue against a uniformly moving, single crust and instead support a segmented early plate model with relative motion between blocks.

The conclusions combine new paleomagnetic data with reanalysis of existing records, contributing to a revised narrative of Earth’s early geologic history and its climate and habitats.

Independent scientist Uwe Kirscher emphasizes the abundance of paleomagnetic data from ancient rocks and its importance for understanding relative plate motion in Earth’s transition to plate tectonics.

Context on today’s plate dynamics: Earth currently has seven major and eight minor plates that move at a few centimeters per year, with most activity at plate margins.

Lead author Alec Brenner and the team conclude that Earth’s lithosphere was already divided into multiple movable segments 3.5 billion years ago, signaling an early move toward modern plate tectonics.

The research is based on 900 rock samples from the East Pilbara Craton in Western Australia, using paleomagnetism to infer ancient latitudes and plate motion through magnetic orientations in minerals.

By establishing an early start to plate tectonics, the study helps explain the formation of Earth's mountains, oceans, climate, and the habitats that supported early microbial life.

Ultimately, this work reframes how we understand Earth's early environment and the conditions that allowed life to thrive.