Researchers used zircons and AI to reconstruct Earth’s ancient crust, revealing possible tectonic processes from the planet’s earliest, rockless chapter.
Researchers from the School of Earth Sciences at Zhejiang University, led by Professors Jia Liu and Qunke Xia, have made a significant breakthrough in exploring a long-lost chapter of Earth’s geological past. Their work, carried out by PhD students Denggang Lu, Zhikang Luan, Jingjun Zhou, and Tianting Lei, offers new insight into what the planet’s continental crust may have looked like during the Hadean eon. This ancient period, which began approximately 4.4 billion years ago, marks the earliest known era in Earth’s history.
“The Hadean is a key period for understanding the origin of Earth’s continents,” said Prof. Jia Liu. “But rocks from this time are incredibly rare. So far, the only known samples are from the Acasta region in Canada and date to about 4.03 billion years ago.” Due to intense geological activity in Earth’s early days, most rocks from that time have been destroyed, leaving behind what scientists call a “missing chapter” in Earth’s story.
Although direct rock samples from this time are almost nonexistent, a remarkably tough mineral called zircon has managed to preserve valuable clues. Some zircon crystals date back more than 4.3 billion years and have been discovered in regions such as the Jack Hills in Australia. These tiny crystals hold geochemical signatures that reveal details about magma activity on the early Earth.
“We don’t know what the actual rocks of the Hadean crust looked like, because we don’t have any—but zircons give us a window into that hidden world,” said PhD student Denggang Lu.
Reconstructing Lost Crust Through AI
To unlock that window, the team compiled the world’s most comprehensive geochemical database to date of igneous zircon and their host rocks—more than 14,000 zircons and 823 matched rock records. Using this database, they trained supervised machine learning models to find patterns between trace elements in zircons and the chemical makeup of their host rocks. This allowed them to predict what the “missing” rocks might have looked like. It’s as if Earth’s earliest rocks had been brought back to life—virtually passed through modern instruments and revealed with chemical details, just like real samples tested in the lab.
“In an age of rapid AI development, using machine learning to uncover the relationship between zircons and their rocks is incredibly exciting,” said Prof. Liu. “It gives us a chance to push the known rock record back by nearly 400 million years and explore how the earliest crust may have evolved.”
The study suggests that the Hadean crust was likely formed through convergent tectonics—similar to what happens during continental collisions—rather than deep oceanic subduction. This points to early forms of plate convergence on the early Earth, offering a new model for primordial crust formation and introducing an innovative approach to studying Earth’s most ancient and elusive rocks. The method not only expands the potential of zircon in early Earth studies but also provides a significant breakthrough in uncovering the planet’s “missing geological chapters.”
Reference: “Earth’s Hadean crust formed via operation of convergent tectonics” by Denggang Lu, Jia Liu, Qunke Xia, Zhikang Luan, Jingjun Zhou, Tianting Lei, Lu Wang and Eero Hanski, 2 June 2025, National Science Review.
DOI: 10.1093/nsr/nwaf230
The study was funded by the National Natural Science Foundation of China.
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