Chicxulub crater rocks record aftermath of dino-killing asteroid
- 5 years ago
AUSTIN, TEXAS — When the massive dino-killing asteroid slammed into the planet millions of years ago, it ended the Mesozoic Era and wiped out nearly 75 percent of all life.
Now, a drilling expedition at the impact site has revealed new details of this world-changing event.
A new study led by the University of Texas at Austin analyzed core samples from the Chicxulub crater in Mexico's Yucatan peninsula. The team used it to assemble a timeline of what happened after the dinosaur-killing asteroid crashed into Earth.
According to a university news release, one of the most notable finds is that roughly 425 feet of material was deposited into the crater in just one day, making it one of the highest rates ever encountered in the geological record.
Researchers estimate that the asteroid struck a shallow ocean some 66 million years ago, hitting it with the force of 10 billion atomic bombs. The blast set the land ablaze, igniting trees and plants up to thousands of miles away.
The impact then triggered a massive tsunami several hundred meters high and moving away from the crater.
According to the New York Times, it also catapulted rock into the upper atmosphere.
Lead author of the study, Sean Gulick, said the largest debris pieces fell back down to Earth in minutes. Smaller particles lingered longer and fell across North America as tektites — glassy orbs that form when molten rock cools while falling.
Charcoal fragments and chemical biomarkers of soil fungi found above sand layers inside the sample indicate that charred remains on land were pulled back into the crater by the receding tsunami waters.
Perhaps the most important discovery made during the study is the absence of sulfur in the core, even though the area around the impact crater is full of sulfur-rich rocks.
This supports the theory that the asteroid impact vaporized sulfur-bearing rocks at the site, releasing the mineral into the atmosphere, where it reflected sunlight away from the planet and caused global cooling.
According to researchers, 325 million metric tons of sulfur is estimated to have been released by the impact. That's about 10,000 times greater than the sulfur spewed by the Krakatoa eruption in 1883, which cooled the Earth by an average of 2.2 degrees Fahrenheit for five years.
Although the asteroid caused destruction at the regional level when it hit, the impact itself was not what killed off the dinosaurs.
Instead, researchers say the global climate change that followed was responsible for the mass extinction of the dinosaurs. Global cooling disrupted photosynthesis, which killed the plants and caused the food chain to collapse.
The nightmarish sequence of events detailed in the study are what scientists have long hypothesized to have happened. Only this time, there's evidence to back it up — and set in stone, no less.
The New York Times reports that early this year, another study found fossils of fish, trees, terrestrial vertebrates, and marine creatures near an ancient lake in North Dakota. Shock waves from the asteroid are believed to have flung them on shore, where they died buried in mud.
As more of the crater core samples are studied and analyzed, many more details will no doubt be revealed about Earth's most destructive day.
Now, a drilling expedition at the impact site has revealed new details of this world-changing event.
A new study led by the University of Texas at Austin analyzed core samples from the Chicxulub crater in Mexico's Yucatan peninsula. The team used it to assemble a timeline of what happened after the dinosaur-killing asteroid crashed into Earth.
According to a university news release, one of the most notable finds is that roughly 425 feet of material was deposited into the crater in just one day, making it one of the highest rates ever encountered in the geological record.
Researchers estimate that the asteroid struck a shallow ocean some 66 million years ago, hitting it with the force of 10 billion atomic bombs. The blast set the land ablaze, igniting trees and plants up to thousands of miles away.
The impact then triggered a massive tsunami several hundred meters high and moving away from the crater.
According to the New York Times, it also catapulted rock into the upper atmosphere.
Lead author of the study, Sean Gulick, said the largest debris pieces fell back down to Earth in minutes. Smaller particles lingered longer and fell across North America as tektites — glassy orbs that form when molten rock cools while falling.
Charcoal fragments and chemical biomarkers of soil fungi found above sand layers inside the sample indicate that charred remains on land were pulled back into the crater by the receding tsunami waters.
Perhaps the most important discovery made during the study is the absence of sulfur in the core, even though the area around the impact crater is full of sulfur-rich rocks.
This supports the theory that the asteroid impact vaporized sulfur-bearing rocks at the site, releasing the mineral into the atmosphere, where it reflected sunlight away from the planet and caused global cooling.
According to researchers, 325 million metric tons of sulfur is estimated to have been released by the impact. That's about 10,000 times greater than the sulfur spewed by the Krakatoa eruption in 1883, which cooled the Earth by an average of 2.2 degrees Fahrenheit for five years.
Although the asteroid caused destruction at the regional level when it hit, the impact itself was not what killed off the dinosaurs.
Instead, researchers say the global climate change that followed was responsible for the mass extinction of the dinosaurs. Global cooling disrupted photosynthesis, which killed the plants and caused the food chain to collapse.
The nightmarish sequence of events detailed in the study are what scientists have long hypothesized to have happened. Only this time, there's evidence to back it up — and set in stone, no less.
The New York Times reports that early this year, another study found fossils of fish, trees, terrestrial vertebrates, and marine creatures near an ancient lake in North Dakota. Shock waves from the asteroid are believed to have flung them on shore, where they died buried in mud.
As more of the crater core samples are studied and analyzed, many more details will no doubt be revealed about Earth's most destructive day.