Scientists from the Universities of Barcelona and Zaragoza in Spain found that large-scale volcanic eruptions did not affect the mass extinction of animals, including dinosaurs, at the end of the Cretaceous. The results of the study, published in the journal Geology, are further evidence in favor of the fall of the asteroid as the cause of the extinction of ancient species.
The researchers analyzed deposits rich in microfossils (microscopic fossils) that range in age from 66.4 to 65.4 million years. The Paleogene period was replaced by the Cretaceous one 66 million years ago. This border coincides with one of the five largest extinctions on Earth. At the same time, global climate changes took place.
Scientists have tested if climatic shifts coincide with massive volcanism on the Deccan Plateau in India and shifts in the Earth's orbit. To do this, they performed an isotopic analysis of carbon-13 in the sediments of the Sumaya rocks, where there are many remains of foraminifera, which became extinct 66 million years ago. These deposits are also characterized by alternating clay or carbonate rich rocks. This rhythm is associated with cyclical changes in the orientation and tilt of the Earth's axis.
It turned out that the extinction of foraminifera coincides with climatic disturbances and the accumulation of impact glass spheres due to the fall of the asteroid. Scientists have also identified three episodes of climate change, two of which are associated with a shift in the Earth's axis, and one with trap volcanism. None of these events caused the Late Cretaceous mass extinction of species.
