USA: The eruption of the mountain creates an ash cloud that covers the Earth, blocking sunlight from falling and causing the temperature to drop sharply.
A volcanic eruption pushed the northern hemisphere back into the ice age. Photo: Earth.
Ancient sediments in Hall Cave, Texas, indicated that volcanic eruption was most likely the cause of the sudden drop of 3 degrees Celsius on Earth about 13,000 years ago, Science Daily reported on July 31. This cold Earth event is known as the Younger Dryas. Michael Waters, director of the Center for Native American Studies and professor of Texas A&M University, and colleagues from Baylor University and the University of Houston published the new study in the journal Science Advances.
Before that, some scientists thought that Younger Dryas was caused by a collision with another celestial body. This event also contributed to the extinction of several large mammals that used to live in North America such as mammoths, horses and camels.
Cave Hall holds sediments dating back more than 20,000 years. Waters said he began researching the cave in 2017. “Is there an alien collision near the end of the latest ice age, which means about 13,000 years ago, when the ice sheets that covered Canada were melting, causing the temperature to suddenly drop and pushing the Northern Hemisphere into an ice age for another 1,200 years? ”he asked.
“New research shows that the geochemical characteristics associated with the Younger Dryas event are not unique, but happened four times over the period 9,000-15,000 years ago. Therefore, the cause of this event did not come. from outer space, “explains Alan Brandon, professor of Earth science at the University of Houston.
Brandon and Nan Sun, a scientist at the University of Houston, conducted isotope analysis of sediment samples collected from Hall Cave. They found that the proportion of elements such as iridium, ruthenium, platinum, palladium and rhenium is not reasonable, meaning that the meteorite was not the cause of the Younger Dryas. “Isotope analysis and relative proportions of the elements match those we find in volcanic gas,” Sun said.
After the volcano erupted, aerosols (aerosols) spread everywhere, reflecting the solar radiation reaching the Earth. This can lead to global cooling after the eruption 1-5 years, depending on the size and length of the disaster. The volcanic eruptions cause the greatest decrease in temperature near the source, usually in the same year the event occurred. Over the following years, the cooling became much weaker.
The team also said that the Younger Dryas event lasted about 1,200 years. Consequently, volcanic eruptions were an important cause, but other changes in the Earth such as colder oceans and more snow cover also contributed to the maintenance of this cold period.
(According to Science Daily)