Contrary to popular belief, large-scale volcanic eruptions could hardly have led to the extinction of dinosaurs in the late Mesozoic. This is the conclusion reached by scientists, the authors of an article in the journal Nature Geoscience.
In Western paleontology, it is generally accepted that volcanic activity played a decisive role in the extinction of lizards: it changed the environment familiar to dinosaurs, making it unsuitable for life. Eruption products (dust and sulfur dioxide) have been emitted into the atmosphere for many decades in a row. Volcanism of the Mesozoic era, at the end of which the dinosaurs became extinct, is usually associated with basalt flows. In the places of distribution of the latter, volcanoes erupted for no more than several decades, and between periods of activity they dormant from hundreds to thousands of years.
Scientists from the University of Leeds (UK) decided to check if this time is enough to damage the biosphere. They modeled the spread of sulfurous gases similar to the emissions from volcanic eruptions that led to the formation of the Deccan Traps and the magmatic province of the Columbia River.
It turned out that a decade-long eruption like the Deccan would have lowered the Earth's surface temperature by only 4.5 degrees Celsius. For comparison: catastrophic for humans, but not destructive for the biosphere as a whole, "volcanic winter" after the eruption of Toba (about 77 thousand years ago) gave a cooling of 4-10 degrees. At the same time, the ambient temperature was restored already 50 years after the abatement of the volcanoes. Finally, although acid mists could kill sensitive vegetation, in general, marine and terrestrial ecosystems were resistant to such influences.
The new model will force scientists to take a fresh look at the causes of the extinction of dinosaurs. Volcanoes and asteroids were previously recognized as the main culprits in the death of lizards. So, in 2014, geologists discovered that 250 thousand years before the fall of the Chiksulub meteorite, a powerful series of eruptions began, lasting half a million years. In addition, there is a "double impact" hypothesis, according to which the fall of a meteorite in the Gulf of Mexico, paired with a magma eruption, jointly destroyed the dinosaurs.
Domestic paleontologists generally adhere to the biospheric version of extinction: the gradual disappearance of dinosaurs due to the appearance of flowering plants (and the evolution of mammals feeding on them) and the cooling of the climate.