Earth's orbit may trigger massive volcanic eruptions

A recent study has uncovered a link between our planet’s changing path around the sun and periods of intense volcanic eruptions.

Researchers studying ancient rocks and seafloor cores have identified signals that appear tied to these rhythmic variations in Earth’s orbit, which may have affected global climates on timescales of ten thousand to a million years.

Thomas Westerhold from the Center for Marine Environmental Sciences (MARUM) has used geological data to piece together climate archives from both the South Atlantic and the Northwest Pacific.

By aligning these records down to a 5,000-year scale, Westerhold and his colleagues found critical points in time when planetary climate shifts coincided with major volcanic activity.

The orbital connection

These new findings challenge the notion that quasiperiodic variations in Earth’s orbit merely influence climate through changes in incoming solar radiation.

The possibility that these orbital cycles also set the stage for eruptions adds another layer to our understanding of how the planet’s interior and exterior forces interact.

“Just like a metronome, we used the rhythmic changes in solar insolation imprinted in geological data to synchronize geological climate archives from the South Atlantic and the Northwest Pacific,” said Westerhold.

“These key records span the last million years of the Cretaceous and are synchronized down to 5,000 years or less, geologically a blink of an eye 66 million years ago.”

Scientists already knew that large igneous provinces, or flood basalt eruptions, could release significant amounts of sulfur dioxide and carbon dioxide into the atmosphere.

By stacking these massive volcanic outpourings on top of orbital-driven temperature swings, the stage was apparently set for dramatic climate swings in a relatively short time.

Ocean sediments reveal past eruptions

“The formation of the flood basalts and its subsequent weathering will leave a geochemical fingerprint in the ocean,” explained co-author Junichiro Kuroda from the University of Tokyo.

“Therefore, we measured the Osmium isotope composition of the South Atlantic and the Northwest Pacific deposits. They should show the same fingerprint at the same time.”

This was another key piece of the puzzle: the hunt for a clear marker in deep-sea sediments. 

Samples from those ocean cores revealed two distinct changes in osmium isotopes. These changes matched previously dated pulses of massive volcanism in India’s Deccan Traps, which are about 1.24 miles thick in places.

“To our surprise we found two steps in the Osmium isotope composition in both oceans contemporaneous with major eruption phases of the Deccan Traps in the latest Cretaceous. And even more surprising, those steps had different impacts on the environment as recorded by fossil remains in the drill cores,” said Westerhold.

Volcanic eruptions linked to mass extinctions

Giant volcanic eruptions have long been tied to major ecological upheavals.

Studies have suggested that flood basalt events played a central role in several mass extinctions, possibly through toxic gas releases and global temperature shifts that strained ecosystems.

“The volume of the erupted flood basalt must have been much larger than previously thought during this early phase of Deccan Trap volcanism. And the related distinct emissions of carbon and sulfur dioxide had diverse effects on the global climate system,” said Don Penman from the Utah State University.

These findings build on earlier evidence suggesting that greenhouse gases from intense volcanic activity may spike temperatures. Yet when sulfur emissions arrive in the upper atmosphere, they can produce complex cooling or warming patterns that can change ocean chemistry.

Weathering, warming, and the carbon puzzle

Weathering of volcanic rocks often draws carbon dioxide out of the air as minerals break down. But if the eruptions themselves add large bursts of greenhouse gases, the balance tips.

This interplay may show why one wave of eruptions caused modest warming, while a later pulse had more pronounced effects.

Early pulses could have been especially rich in sulfur, hitting local habitats hard but not causing a massive global temperature rise. Later periods likely unleashed more carbon-heavy emissions, shifting global temperatures upward and leaving distinct signs in marine fossils.

Why this matters now

Researchers stress that the planet’s deep past carries lessons for modern climate dynamics. Although today’s changes stem mainly from human activities, extreme volcanic events show how quickly the climate system can react when pushed.

This work also reveals the importance of precise dating in geological research. High-resolution age models provide the magnifying glass needed to see correlations between Earth’s orbital rhythms, volcanic eruptions, and environmental changes.

The team’s approach shows that even small differences in dating can mask or unveil key connections in Earth’s history. Matching up ocean sediment records in fine detail helps scientists identify which events happened simultaneously, offering a clearer picture of cause and effect.

These insights highlight that our world’s climate has always been shaped by both internal forces, such as molten rock movements, and external cycles influenced by cosmic mechanics.

Looking at these linked changes over millions of years can inform how we view climate shifts on much shorter timescales.

The study is published in the journal Science Advances.

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