Introduction: 66 million years ago, a massive asteroid collision with Earth caused a catastrophic event that led to the extinction of non-avian dinosaurs and numerous other species. New research suggests that the primary driver of this mass extinction was the clouds of dust generated by the impact, which blocked out the sun for 15 years.
The Impact and its Consequences:
- When the Chicxulub impactor hit Earth, it released sulphur-based gases and silicate dust into the atmosphere.
- Wildfires were triggered globally, emitting soot and carbon dioxide.
- The resulting “impact winter” lasted 15 years and resulted in the extinction of 75% of species on the planet.
Re-evaluating the Role of Silicate Dust:
While previous research focused on the effect of sulphuric gas emissions and soot injections from wildfires, the role of silicate dust has been largely overlooked.
A study conducted by Cem Berk Senel and colleagues at the Royal Observatory of Belgium in Brussels analyzed fine-grained material from North Dakota deposited during the Chicxulub impact. The researchers discovered that the silicate dust persisted in the atmosphere for 15 years, playing a significant role in sustaining the global winter.
The Impact of Silicate Dust:
- The silicate dust alone led to a 15°C drop in Earth’s surface temperature.
- It was more effective than sulphur gases in blocking sunlight, which hindered photosynthesis in plants and phytoplankton.
- Long-lasting photosynthetic shutdown caused a lack of food and triggered a series of extinctions on land and in the oceans.
Future Studies:
Senel and his colleagues plan to further investigate the long-term climatic effects of the asteroid impact. They aim to unravel the mysteries surrounding one of the largest mass extinction events in history and understand the impacts on life.
