Revealing Findings: How Volcanic Activity Wasn’t the Culprit Behind Dinosaur Extinction!

A meteor struck Earth roughly 66 million years ago, close to the area now known as the Yucatán peninsula, leading to extensive devastation and loss of life. Concurrently, significant volcanic activity blanketed a large portion of the Indian subcontinent with over 2 kilometers of lava flows. Researchers have long contended whether the impact or the volcanic supereruption was the primary reason for the extinction of 75% of all species that existed at that time, including non-avian dinosaurs, or if it was due to a combination of factors.

A new investigation conducted by scientists from Utrecht University and the University of Manchester reveals that although the volcanism resulted in a brief climate shift, the impact of these changes had already diminished thousands of years prior to the meteor strike, allowing most species to survive this initial cold period. Consequently, they conclude that the meteorite impact was the main reason behind the mass extinction event at the conclusion of the Cretaceous period.

A meteorite strike can create a dense layer of dust and soot that obstructs sunlight and results in surface cooling. Volcanic eruptions emit enormous quantities of carbon dioxide, dust, and sulfur, leading to significant changes to the atmospheric chemistry and modifying Earth’s climate—but in distinct manners and at different timescales compared to a meteor impact.

The team analyzed fossil molecules found in sediments formed around 65 to 66 million years ago within the North American continent, allowing them to reconstruct the air temperatures for the entire duration of that period.

The investigated sediments encompass distinct molecules produced by bacteria. The configuration of these molecules varies according to the temperature of the environment where the bacteria once thrived. By examining the makeup of these molecules within sedimentary layers formed annually, researchers reconstructed a climatic timeline that included both the volcanic activities and the meteor impact.

The research indicates that a significant volcanic event transpired roughly 30,000 years prior to the meteor strike, aligning with at least a 5-degree decline in climate temperatures. They also deduce that this cooling likely stemmed from emissions of volcanic sulfur.

“These volcanic activities and their associated releases of carbon dioxide and sulfur would have had severe impacts on Earth’s biota. However, these occurrences took place thousands of years before the meteor impact and likely contributed only minimally to the extinction of the dinosaurs,” remarks study author Lauren O’Connor, a geochemist at Utrecht University.

The researchers further found that by around 20,000 years ahead of the meteor impact, Earth’s temperatures had already stabilized and returned to levels comparable to those before the onset of volcanic eruptions. This rapid recovery was likely facilitated by volcanic emissions acting like greenhouse gases, which warmed the planet swiftly.

With the influence of volcanism largely excluded, this indicates that the Yucatán meteor impact is the principal factor responsible for the subsequent mass extinction.

“In contrast, the asteroid’s impact triggered a series of disasters, including wildfires, earthquakes, tsunamis, and an ‘impact winter’ that obstructed sunlight and devastated ecosystems. We maintain that the asteroid ultimately delivered the fatal blow,” concludes Rhodri