The dinosaur killer asteroid which slammed into Earth 66 million years ago also triggered a giant tsunami with mile-high waves in the Gulf of Mexico whose waters have traveled half the world, according to a new study.
Researchers found evidence of this monumental tsunami after analyzing cores from more than 100 sites around the world and creating digital models of the monstrous waves after the asteroid impacted Mexico’s Yucatán Peninsula.
“This tsunami was strong enough to disrupt and erode sediment in ocean basins halfway around the world,” said study lead author Molly Range, who conducted the modeling study for a thesis. master’s degree in the Department of Earth and Environmental Sciences at the University of Michigan. in a report.
Research on the one kilometer high tsunamiwhich was previously presented at the 2019 American Geophysical Union Annual Meeting, was published online Tuesday, October 4 in the journal Advances AGU.
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Range dove into the course of the tsunami immediately after the asteroidthe collision. Based on previous findings, his team modeled an asteroid that measured 8.7 miles (14 kilometers) in diameter and was speeding at 27,000 mph (43,500 km/h), or 35 times the speed of sound when it hit. hit the Earth.
After the asteroid impact, many life forms died; the nonavian dinosaurs died (only birds, which are living dinosaurssurvive today) and about three-quarters of all plant and animal species were wiped out.
Researchers know many of the the perverse effects of the asteroidlike starting raging fires that cooked animals alive and pulverizing sulfur-rich rocks that led to deadly acid rain and extended overall cooling.
To learn more about the resulting tsunami, Range and his colleagues analyzed Earth’s geology, successfully analyzing 120 “boundary sections” or marine sediments deposited just before or after the mass extinction event, which marked the end of the Cretaceous period.
These boundary sections matched their model’s predictions of wave height and motion, Range said.
The initial energy of the impact tsunami was up to 30,000 times greater than the energy released by the tsunami from the December 2004 Indian Ocean earthquake that killed more than 230,000 people, researchers have found. .
Once the asteroid hit Earth, it created a 100 km wide crater and threw a dense cloud of dust and soot into the atmosphere.
Just 2.5 minutes after the strike, a curtain of ejected material pushed a wall of water outward, briefly creating a 2.8-mile (4.5 km) high wave that then crashed that the ejecta fell towards Earthaccording to simulation.
After 10 minutes, a 0.93 mile (1.5 km) high tsunami wave about 137 miles (220 km) from the impact site swept across the gulf in all directions. An hour after impact, the tsunami had left the Gulf of Mexico and rushed into the North Atlantic.
Four hours after impact, the tsunami crossed the Central American Seaway – a passage which at the time separated North America from South America – and into the Pacific.
A full day after the asteroid’s collision, the waves had crossed most of the Pacific and Atlantic, entering the Indian Ocean on both sides and touching most of the globe’s coastlines 48 hours after the strike.
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The power of the tsunami
After impact, the tsunami radiated primarily east and northeast, spouting into the North Atlantic Ocean, as well as southwest through the Central American Seaway flowing into the Pacific Ocean. South.
The water moved so quickly in these areas that it likely exceeded 0.4 mph (0.6 km/h), a speed that can erode fine-grained sediments from the sea floor.
Other regions largely escaped the tsunami’s power, including the South Atlantic, North Pacific, Indian Ocean and present-day Mediterranean Sea, according to the team’s models.
Their simulations showed that water velocities in these areas were below the 0.4 mph threshold.
The team even found outcrops – or exposed rock deposits – from the impact event on the North and South Islands of eastern New Zealand, more than 12,000 km from the Chicxulub crater in Mexico.
Originally, scientists thought these outcrops were the result of local tectonic activity. But due to their age and location on the modeled tsunami route, study researchers pinned it to the asteroid’s massive waves.
“We believe these deposits record the effects of the tsunami impact, and this is perhaps the most telling confirmation of the global significance of this event,” Range said.
Although the models did not assess coastal flooding, they revealed that open-ocean waves in the Gulf of Mexico would have exceeded 328 feet (100 m) and wave heights would have reached over 32.8 feet. (10m). The tsunami approached coastal regions of the North Atlantic and parts of the Pacific coast of South America, the statement said.
As the water became shallow near the coast, the wave height would have increased dramatically.
“Depending on the geometry of the coast and wave progression, most coastal regions would be flooded and eroded to some degree,” the authors wrote in the study. “All historically documented tsunamis pale in comparison to such global impact.”
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This article was originally published by Live Science. Read the original article here.