For decades, scientists have debated the causes behind the mass extinction event that wiped out the dinosaurs 66 million years ago. While the Chicxulub meteorite impact has been widely regarded as the primary culprit, massive volcanic eruptions in India, known as the Deccan Traps, were also considered a potential factor. New research, however, reveals that these volcanic events occurred tens of thousands of years before the meteorite impact, with minimal influence on the dinosaurs’ extinction.
The Deccan Traps eruptions released enormous amounts of sulfur dioxide, carbon dioxide, and ash into the atmosphere, altering the Earth’s climate. These eruptions have been linked to a temporary cooling period caused by sulfuric aerosols reflecting sunlight away from the Earth’s surface. However, their timeline and impact on ecosystems have remained contentious.
Scientists from Utrecht University and the University of Manchester have now provided compelling evidence that the effects of these eruptions subsided long before the meteorite impact. By analyzing ancient molecules preserved in peatlands, they reconstructed Earth’s air temperatures around the time of the extinction, offering new insights into the sequence of events.

The researchers examined fossilized molecular structures from ancient sediments in the United States. These molecules, produced by bacteria, shift their composition based on environmental temperatures. This allowed scientists to create a detailed timeline of climate changes during the late Cretaceous period.
Their findings revealed that significant volcanic activity occurred around 30,000 years before the meteorite impact. During this period, Earth’s temperature dropped by at least 5°C, likely due to sulfur emissions from the volcanoes. However, the cooling period was brief. By approximately 20,000 years before the meteorite impact, temperatures had stabilized, returning to pre-eruption levels due to the warming effects of volcanic CO₂.
In contrast to the localized and temporary effects of volcanic activity, the Chicxulub meteorite caused catastrophic global disruptions. Upon impact, it released an unimaginable amount of energy, triggering earthquakes, tsunamis, and massive wildfires. The aftermath included a “nuclear winter”, as dust and soot blocked sunlight, leading to the collapse of ecosystems dependent on photosynthesis.

This chain of events created conditions incompatible with the survival of large terrestrial animals, including the dinosaurs. The asteroid impact was the definitive factor in their extinction, stated Dr. Rhodri Jerrett of the University of Manchester. The timing of volcanic activity, as this study shows, means it likely played only a minor role, if any, in the mass extinction.
This groundbreaking research not only clarifies the cause of the dinosaurs’ extinction but also showcases the potential of molecular fossils in unraveling Earth’s climatic history. By identifying and analyzing ancient temperature records, scientists can better understand how past climate events influenced life on Earth.
The team is now applying this approach to study other critical periods in Earth’s history, providing a clearer picture of how natural disasters have shaped the evolution of life.
SOURCES
Lauren K. O’Connor, Rhodri M. Jerrett, et al., Terrestrial evidence for volcanogenic sulfate-driven cooling event 30 kyr before the Cretaceous–Paleogene mass extinction. Science Advances, 2024; 10 (51) DOI:10.1126/sciadv.ado5478
Discover more from LBV Magazine English Edition
Subscribe to get the latest posts sent to your email.