Scientists have revealed a new theory challenging the long-held belief that an asteroid impact was solely responsible for the extinction of the dinosaurs. According to a team led by the Royal Observatory of Belgium, it was debris ejected by the impact that played a critical role. The team found that dust from pulverized rock was thrown into Earth's atmosphere, blocking the sun and hindering plant photosynthesis.
New modeling conducted by the researchers showed that the amount of dust exceeded 2,000 gigatonnes, which is over 11 times the weight of Mt. Everest. This massive amount of dust lingered in the atmosphere for up to 15 years, causing a widespread nuclear winter. As a result, vegetation died off, leading to the starvation of many herbivorous species, including some dinosaurs, and ultimately resulting in the catastrophic mass extinction event that wiped out 75 percent of living creatures on Earth.
The discovery of the Chicxulub Crater in 1978 had previously led scientists to believe that the asteroid impact was enough to drive the dinosaurs to extinction. However, this recent research based on particles found at the Tanis fossil site in North Dakota suggests that dust kicked up by the asteroid was the primary cause of the impact winter.
The dust particles found at the Tanis site were of the perfect size to stay in the atmosphere for up to 15 years. By inputting this data into climate models, the researchers were able to determine that dust likely played a much more significant role in the mass extinction than initially thought. Out of all the material ejected by the asteroid, they estimated that 75 percent was dust, 24 percent sulfur, and one percent soot.
While this study does not provide a definitive answer to the question of what caused the impact winter, it offers an important contribution to the ongoing pursuit of understanding the last mass extinction event on Earth. Scientists believe that uncovering the circumstances of this event is crucial for gaining insights into both the past and future, including the potential for predicting future mass extinctions.