Currently, the main cause of the extinction of dinosaurs is the fall of the asteroid. However, some scientists believe that the extinction process had begun much earlier and now, there is evidence for this.
The direct fall of the asteroid could not kill everyone at once. Climate changes that subsequently occurred, such as an increase in the acidity of water on Earth, giant dust clouds that blocked sunlight, etc. became fatal.
Recent studies by the scientists at the University of Michigan show that catastrophic climate changes had begun several tens of thousands of years before the asteroid fell. The reason for this was the powerful eruptions of volcanoes that lasted about a million years and, in particular, formed the Deccan Traps in India with an area of half a million square kilometers.
In the course of the research, scientists studied the remains of mollusk shells, whose age is more than 66 million years. It turned out that at that time, there was a sharp increase in the level of mercury and carbon dioxide, which indicates a strong volcanic eruption.
The level of mercury pollution was very strong. Today, in some industrial areas, the level of mercury pollution is particularly high. Scientists believe that during the period of volcanic eruptions, such pollution was widespread throughout the planet. Moreover, the environmental impact of mercury continued for several tens of thousands of years.
Thus, scientists believe that the catastrophic climate changes that led to the death of dinosaurs began precisely with the eruption of volcanoes and subsequent atmospheric mercury pollution. However, this does not negate the fact that the subsequently fallen asteroid contributed to the extinction process.