The study addresses a critical gap in Earth's geological timeline. "The Hadean is a key period for understanding the origin of Earth's continents," said Prof. 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." Most original rock material from this era has been lost due to early Earth's dynamic interior processes.
Despite this, ancient zircons-durable minerals dating back more than 4.3 billion years and found in places like Australia's Jack Hills-have preserved geochemical clues from that era. "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," explained PhD student Denggang Lu.
To interpret these clues, the team built the largest global database of igneous zircons and their host rocks, encompassing over 14,000 zircons and 823 rock records. They then trained supervised machine learning models to detect patterns between zircon trace elements and the chemistry of their parent rocks. This predictive modeling allowed the researchers to reconstruct the likely composition of Earth's earliest continental crust.
"In an age of rapid AI development, using machine learning to uncover the relationship between zircons and their rocks is incredibly exciting," Prof. Liu noted. "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."
Their findings point to a formation process driven by convergent tectonics-similar to present-day continental collisions-rather than deep oceanic subduction. This model supports the idea that proto-plate tectonic activity was already underway during Earth's infancy, reshaping theories of early crust development and enhancing the role of zircon analysis in deep-time studies.
Research Report:Earth's Hadean crust formed via operation of convergent tectonics
Related Links
School of Earth Sciences, Zhejiang University
Tectonic Science and News
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
