Meteorite vs. Volcanism: The Great Debate
The Chicxulub meteorite crash in the Gulf of Mexico is well known as the huge disaster that wiped out the dinosaurs. But the massive volcanic eruptions in India, called the Deccan Traps, also played a role. These eruptions released a lot of CO₂, sulphur, and dust into the air, which changed the Earth’s climate. This caused short-term cooling and long-term warming. The question is: how much did these changes really affect the extinction of the dinosaurs?
Greg Price, Rhodri Jerrett and Lauren O’Connor sampling fossilised peats at West Bijou, USA. Photo: Tyler Lyson.
New Insights from Ancient Peats
The research team used ancient peat samples from the United States to study air temperatures around the time of these events. They found that a large volcanic eruption happened about 30,000 years before the meteorite hit, causing global temperatures to drop by 5°C. This cooling, caused by volcanic sulphur blocking sunlight, lasted for about 10,000 years. By 20,000 years before the meteorite impact, temperatures had returned to normal, helped by volcanic CO2 emissions.
Lauren O’Connor, a scientist from Utrecht University, said, “These volcanic eruptions and the release of CO2 and sulphur had a big impact on life on Earth. But these events happened thousands of years before the meteorite impact and probably didn’t play a major role in the extinction of the dinosaurs.”
The Fatal Blow: Chicxulub Meteorite Impact
New studies highlight the terrible damage caused by the Chicxulub meteorite crash. While volcanic activity can cause short-term climate shifts, the meteorite set off a chain of extreme disasters: massive fires, huge ocean waves, earthquakes, and a long period of darkness called an “impact winter” that blocked the sun and wiped out ecosystems.
Rhodri Jerrett from the University of Manchester explains, “The asteroid caused a series of events that destroyed life on Earth. We think it was the asteroid that finally caused the extinction.”
Reconstructing Earth’s Past Climate
The researchers used a new method to study old fossil molecules found in ancient soil layers. These molecules, made by bacteria, change their shape depending on the temperature of the environment. By looking at these changes, scientists were able to build a clear timeline of temperatures before the extinction event.
This approach not only helped understand when the volcanic activity and meteorite impact happened but also provided a fresh way to explore other important moments in Earth’s past.
Conclusion
The scientists tried a new way to study old fossil molecules discovered in ancient soil layers. These molecules, created by bacteria, change their form based on the temperature of their surroundings. By examining these changes, researchers could create a detailed timeline of temperatures before the extinction event.
This method not only helped figure out when the volcanic eruptions and meteorite strike occurred but also offered a new approach to studying other key events in Earth’s history.
Reference
According to a recent publication in Science Advances by O’Connor et al. (2024), the volcanic eruptions that occurred before the meteorite impact likely played a small role in the extinction event. You can read more about the study here.