New hypothesis about the cause of dinosaur disappearance

US scientists have discovered more evidence that volcanic activity may have destroyed all the dinosaurs on earth, not because of meteorites that fell as previous theories.

Photo: softpedia.com.

Extensive extinction about 65 million years ago ended the dinosaur dominance on Earth and also completely destroyed 70% of the planet's species at that time.

Hypothesis of the extinction of dinosaurs by the impact of the Earth collision with a giant meteorite was proposed by physicist Luis Walter Alvarez in 1980, according to which a large hole collision named Chicxulub on sale. Mexico's Yucatan island. Geophysicist Glen Penfield found Chicxulub in a search for oil. This giant hole is about 65 million years old, coinciding with the time of the dinosaurs extinction.

However, in recent decades, many scientists believe that changing climate and volcanic activity can also cause dinosaurs to become extinct. One of the advocates of the volcanic hypothesis is the geologist Gerta Keller of Princeton University (USA). She thought that sulfur dioxide (SO ₂ ) gas escaped from volcanoes in India during the Cretaceous period that destroyed all dinosaurs.

Gerta pointed out that, about 63 to 67 million years ago, Earth once witnessed the appearance of hundreds of giant volcanoes. Their lava makes up the vast Deccan plateau in India today. Gerta estimates that initially lava covered an area of ​​up to 1.5 million square kilometers (more than twice the size of the state of Texas in the US).

When active, volcanoes release SO ₂ , dust and other gases into the atmosphere, causing the Earth's climate to change. The interaction between SO ₂ and air causes the planet's surface temperature to drop and create acid rain. Those two changes are not conducive to dinosaurs.

After the volcanic hypothesis was announced, many scientists believed that the combination of meteorites and volcanoes could be a possibility. According to them, the collision between the globe and a giant meteorite is the later event, but acts as the "final slash" to bring the entire dinosaurs to the afterlife.

Gerta and colleagues studied geological data in India, Texas and Mexico to determine the role of volcanoes on the extinction of dinosaurs. After examining the sediments, the team found the impact that meteorites caused about 300 thousand years before the dinosaurs became extinct.

'Meanwhile, the impact of the Deccan lava region occurred just before the time of the dinosaurs' extinction,' said Vincent Courtillot, a geophysicist at the University of Paris (France) and joined the research team.

According to Gerta and Vincent, dinosaurs were almost destroyed immediately after the first lava eruption. Two subsequent eruptions prevented them from recovering. By the time of the mail, dinosaurs completely disappeared. Vincent compared the mass of SO ₂ released from Chicxulub and Deccan lava. He noticed the volcano erupted much more SO2.

For example, the eruption of Pinatubo volcano in 1991 caused the Earth's atmosphere to receive about 17 million tons of sulfur dioxide (SO ₂ ). Chicxulub pits also release between 50 and 500 billion tons of SO2, but the amount of SO2 escaping from volcanoes creates Deccan lava areas of up to 10 trillion tons.

Based on these comparisons, Vincent thinks that the possibility of volcanoes pushing dinosaurs into extinction is huge. "We have underestimated the impact of volcanoes and overestimated the role of meteorites," Gertas said.