New research reveals that rapid volcanic eruptions, not warming temperatures, were the primary cause of the Triassic-Jurassic extinction event 201.6 million years ago.
The new study has changed our understanding of a major event in Earth's history known as the Triassic-Jurassic extinction, which occurred about 201.6 million years ago.
The extinction event wiped out approximately three-quarters of all living species on the planet, marking the end of the Triassic period and the beginning of the Jurassic period, when dinosaurs emerged as the dominant species.
Previously, scientists believed that the extinction was caused by rising temperatures due to high levels of carbon dioxide released by massive volcanic eruptions. These eruptions split the supercontinent Pangaea and released millions of cubic miles of lava over hundreds of thousands of years.
However, the new study suggests a different story: instead of warmth, it was cold that played a crucial role in this extinction.
Rapid Eruptions Triggered Cooling, Leading to Mass Extinction
Researchers found evidence that the first pulses of lava from these eruptions were actually rapid events that lasted less than a century. When these volcanoes erupted, they released large amounts of sulfate particles into the atmosphere. These particles reflected sunlight, leading to a dramatic drop in temperatures.
The sudden cooling, often called "volcanic winter," was devastating to many species that were unable to adapt quickly enough to the changing environment.
The study, published in the Proceedings of the National Academy of Sciences, highlights that while carbon dioxide takes a long time to affect temperatures, the cooling effect of sulfate particles happens almost instantly. This means that the rapid volcanic activity created conditions that were immediately harmful to many organisms living at the time.
The researchers studied rocks from regions like Morocco, Nova Scotia, and New Jersey to gather data on the timing of these eruptions. They discovered that the lava pulses occurred in quick succession, leading to a concentrated impact on the environment.
The findings indicate that the volcanic eruptions from the Central Atlantic Magmatic Province, or CAMP, were not only massive but also occurred over a much shorter time frame than previously thought.
Many species, including various plants and animals that thrived in the Triassic, disappeared with these eruptions. Small feathered dinosaurs and other resilient creatures managed to survive, likely because their size allowed them to find shelter in burrows.
