The study, led by researchers at the University of Edinburgh, analyzed the chemical composition of fossilized fish scales and plant material found at a site in present-day Scotland. The site, known as the Isle of Skye, was once part of a shallow sea located near the edge of the North Atlantic Ocean. The researchers found that the chemical composition of the fossilized material changed dramatically over time, indicating a significant environmental change.
Specifically, the researchers found that the levels of iridium—an element that is rare in the Earth's crust but abundant in asteroids and comets—were elevated in the fossilized material. However, the levels of iridium were not as high as would be expected if an asteroid had directly impacted the Earth. Instead, the researchers suggest that the iridium was released into the environment from volcanic eruptions that occurred in the region prior to the dinosaur extinction.
The researchers also found evidence of changes in the climate at the time of the dinosaur extinction. The fossilized material showed that the temperature of the ocean increased significantly, and the water became more acidic. These changes would have been harmful to many marine organisms, including the phytoplankton that formed the base of the food chain.
The study suggests that the combination of massive volcanic eruptions and changes in climate led to the extinction of the dinosaurs. The volcanic eruptions released toxic gases and ash into the atmosphere, blocking out the sun and causing global cooling. The changes in climate caused sea levels to rise and the oceans to become more acidic. These combined effects created a harsh environment that many species were unable to survive.
The new study provides a more nuanced understanding of the extinction of the dinosaurs. While an asteroid impact may have played a role in the extinction, it was likely just one of many factors. The massive volcanic eruptions and changes in climate were also significant contributors to the demise of the dinosaurs.
