All complex life on Earth may be the result of plate tectonics tearing apart the ancient supercontinent Nuna 1.5 billion years ago, according to new research out of Australia.
Professor Dietmar Müller of the University of Sydney’s EarthByte Group led the work, joined by colleagues from the University of Adelaide, as they studied the formation of early oceans. Their findings on the emergence of life through Earth’s transforming environment were presented in a paper published in Earth and Planetary Science Letters.
“Our approach shows how plate tectonics has helped shape the habitability of the Earth,” lead author Professor Dietmar Müller said. “It provides a new way to think about how tectonics, climate, and life co-evolved through deep time.”
The Boring Billion
Traditionally, scientists characterized the period as one of stasis and inactivity, during which little geological or biological development occurred. This era was considered so inconsequential that it was even called the “Boring Billion,” spanning 1.8 to 0.8 billion years ago. Now, new work on this neglected period is overturning these assumptions.
Müller’s team instead found that the violence of plate tectonics gave rise to oxygen-rich oceans. Those new environments, in turn, served as the birthplace of the first eukaryotes, organisms with a distinct nucleus and membrane-bound structures. All of our planet’s plants, animals, and fungi fall into this class, descended from those early eukaryotes.
“Our work reveals that deep Earth processes, specifically the breakup of the ancient supercontinent Nuna, set off a chain of events that reduced volcanic carbon dioxide emissions and expanded the shallow marine habitats where early eukaryotes evolved,” Müller said.
Nuna and Life
Despite its name, the period known as the Boring Billion saw Earth form and then pull apart a single supercontinent twice, first producing what geologists call Nina, and then later producing Rodinia. After tracing back 1.8 billion years of plate tectonic history through a computer model, the researchers identified continental margins, plate boundaries, and even carbon exchange between the atmosphere, oceans, and mantle over this vast span.
According to the team’s findings, Nina broke up roughly 1.46 billion years ago. In the process, the shallow continental shelves extended to 130,000 kilometers, doubling their length and creating more environments conducive to temperate, oxygen-rich waters. The long-term stability of these habitable environments provided the perfect incubator for eukaryotes, the researchers say.
Creating these environments was not enough to advance life on Earth, though. The area did live up to its “boring” reputation in one crucial way: volcanic carbon dioxide outgassing dropped significantly. At the same time, the expanding mid-ocean ridge flanks produced an increased concentration of carbon in ocean crust. When seawater filtered into cracks in the crust, the liquid heated, releasing the carbon dioxide present to form limestone.
“This dual effect—reduced volcanic carbon release and enhanced geological carbon storage—cooled Earth’s climate and altered ocean chemistry, creating conditions suitable for the evolution of more complex life,” said co-author Associate Professor Adriana Dutkiewicz, also from the School of Geosciences at the University of Sydney.
Eukaryotes Appear
The oldest fossil eukaryotes date to roughly 1.05 billion years ago, a bit shy of half a billion years after Nuna broke apart. This would place them around the period when shallow seas would have been greatly expanded.
“We think these vast continental shelves and shallow seas were crucial ecological incubators,” said Associate Professor Juraj Farkaš from the University of Adelaide. “They provided tectonically and geochemically stable marine environments with presumably elevated levels of nutrients and oxygen, which in turn were critical for more complex lifeforms to evolve and diversify on our planet.”
This offers a complex and interwoven picture of the forces that give rise to life. Dynamics deep within the Earth, combined with geochemical processes near the surface, drive biological evolution, integrating the carbon cycle, plate tectonics, and ocean chemistry to produce a foundational spawning ground.
The paper, “Mid-Proterozoic Expansion of Passive Margins and Reduction in Volcanic Outgassing Supported Marine Oxygenation and Eukaryogenesis,” appeared in the Earth and Planetary Science Letters on October 27, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.