Earth’s history has always been a story told through the fossilized remains of long-extinct creatures. For centuries, scientists have used these remnants to piece together the planet’s geological timeline. But recent research has uncovered an astonishing revelation: Earth’s biodiversity could be driven by a deep, tectonically controlled cycle that spans millions of years.
The Tectonic Clock Beneath Our Feet
Geologists have long divided Earth’s history into distinct periods, such as the Jurassic or Cretaceous, based largely on fossil evidence. These periods are marked by significant biological events, particularly mass extinctions.
Traditionally, these extinctions were seen as linked to drastic environmental changes, such as volcanic eruptions or changes in climate. However, a new study published in Communications Earth and Environment suggests there is an even deeper connection at play—one rooted in Earth’s internal, tectonic processes.
The study reveals that a 60-million-year cycle may govern the rise and fall of biodiversity on Earth, with geological events directly influencing the fate of life. Researchers found that these cycles correspond closely with global tectonic activity, such as the shifting of continents and volcanic activity that drives the release of gases like carbon dioxide.
Tying Extinction Cycles to Plate Tectonics
Published in the prestigious journal Nature, the findings are the result of extensive time-series analysis and the correlation of empirical data with geological simulations. The study, led by researchers from multiple institutions, uncovers a striking correlation between tectonic cycles and marine extinction events. The team found that every 60 million years, significant shifts in Earth’s biodiversity mirror tectonic cycles marked by volcanic eruptions, shifts in the Earth’s crust, and subduction processes.
At the heart of this 60-million-year cycle is the movement of Earth’s tectonic plates. As these plates move, they influence the formation of mountain ranges, volcanic arcs, and the chemistry of Earth’s oceans and atmosphere. The team also observed that these shifts coincide with significant mass extinctions, including the well-known end-Permian extinction and the end-Cretaceous extinction that wiped out the dinosaurs.
How Tectonics Influence Earth’s Oceans and Climate
One of the most compelling aspects of this study is how Earth’s tectonic activity directly impacts the oceans’ chemistry, which in turn influences the planet’s climate and biodiversity. Researchers pointed out that tectonic cycles drive oceanic accretion and subduction processes, which influence the balance of gases in the atmosphere, including carbon dioxide.
As volcanic activity increases, so does the release of CO2 into the atmosphere. This causes global temperatures to rise, which, in turn, affects ocean chemistry. The study indicates that warmer ocean temperatures lead to conditions that are less conducive to marine life, creating periods of oxygen depletion in the oceans, a phenomenon known as oceanic anoxia. These oxygen-poor conditions are known to contribute to large-scale extinction events.
The Ripple Effect on Biodiversity
The research team also observed a consistent pattern: increased tectonic activity leads to more frequent and severe extinction events, with the disappearance of entire species. As the tectonic plates continue to shift and reshape the surface of the Earth, the resulting changes in climate and ocean chemistry have direct consequences on marine ecosystems.
Interestingly, the study found that these tectonic cycles are not just isolated to one region. The patterns of extinction and the subsequent recovery of life are global phenomena, affecting marine life across vast distances. The tectonic “clock” does not just affect one species or one ocean; its influence is felt worldwide, shaping the course of evolution itself.