by The dinosaur-killing asteroid that hit Earth 66 million years ago also triggered a mega-tsunami with kilometer-high waves in the Gulf of Mexico, whose waters traveled halfway around the world, according to a new study.
Researchers discovered 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 hit Mexico’s Yucatan Peninsula.
“This tsunami was powerful enough to disturb and erode sediments in ocean basins halfway around the world,” said study lead author Molly Range, who conducted the modeling study for a master’s thesis in the Department of of Earth and Environmental Sciences at the University of Michigan. in a statement.
The tsunami research, previously presented at the 2019 American Geophysical Union Annual Meeting, was published online Tuesday (Oct. 4) in the journal AGU advances.
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Dove into the tsunami’s journey right after the asteroid hit. Based on previous findings, her team modeled an asteroid that was 8.7 miles (14 kilometers) wide and zoomed 27,000 mph (43,500 km/h), or 35 times the speed of sound, when it hit Earth.
After the asteroid hit, many life forms died. the non-avian dinosaurs became extinct (only birds, which are living dinosaurs, survive today) and about three-quarters of all plant and animal species disappeared.
Researchers know of many of the asteroid’s devastating effects, including igniting raging fires that cooked animals alive and pulverizing sulfur-rich rocks that led to deadly acid rain and widespread global cooling.
To learn more about the resulting tsunami, Range and her colleagues analyzed Earth’s geology, successfully analyzing 120 “marginal sections,” or marine sediments that were laid down shortly before or after the mass extinction event that marked the end of the Cretaceous. period.
Those boundary segments matched the model’s predictions of wave height and path, Range said.
The initial energy from the impact tsunami was up to 30,000 times greater than the energy released by the December 2004 Indian Ocean earthquake tsunami that killed more than 230,000 people, the researchers found.
Once the asteroid hit Earth, it created a crater 62 miles (100 km) wide and launched a thick cloud of dust and soot into the atmosphere.
Just 2.5 minutes after impact, a curtain of propellant pushed a wall of water outward, briefly creating a 2.8-mile (4.5 km) high wave that collapsed as the ejecta plummeted back to Earth, according to the simulation.
At the 10-minute mark, a 0.93-mile (1.5 km) tsunami wave about 137 miles (220 km) away from the impact site swept across the bay in all directions. An hour after the impact, the tsunami had left the Gulf of Mexico and rushed into the North Atlantic.
Four hours after the impact, the tsunami passed through the Central American Seaway – a passage separating North and South America at the time – and into the Pacific.
A full day after the asteroid hit, the waves had crossed most of the Pacific and Atlantic, entering the Indian Ocean on both sides and touching most of the planet’s coasts 48 hours after the impact.
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The power of the tsunami
After the impact, the tsunami radiated mainly to the east and northeast, emerging into the North Atlantic Ocean, as well as to the southwest through the Central American Seaway that flows into the South Pacific Ocean.
The water traveled so fast in these areas that it probably exceeded 0.4 mph (0.6 km/h), a speed that can erode fine-grained seafloor sediments.
Other regions largely escaped the tsunami’s force, including the South Atlantic, North Pacific, Indian Ocean and the present-day Mediterranean Sea, according to the team’s models.
Their simulations showed that water velocities in these areas were less than the 0.4 mph limit.
The team even discovered outcrops — or exposed rock deposits — from the impact event on the North and South Islands of eastern New Zealand, more than 7,500 miles (12,000 km) from the Chicxulub crater in Mexico.
At first, scientists believed that these protrusions came from local tectonic activity. But because of their age and location in the modeled tsunami path, the study’s researchers chalked it up to the asteroid’s massive waves.
“We feel that these deposits record the effects of a tsunami of impacts, and this is perhaps the most definitive confirmation of the global significance of this event,” Range said.
Although the models did not estimate coastal flooding, they revealed that open ocean waves in the Gulf of Mexico would have exceeded 328 feet (100 meters) and waves would have reached heights of more than 32.8 feet (10 meters) The tsunami approached coastal areas of the North Atlantic and parts of the Pacific coast of South America, according to the release.
As the water became shallow near the shore, the height of the waves would have increased dramatically.
“Depending on coastal geometry and advancing waves, most coastal areas will be inundated and eroded to some extent,” the authors wrote in the study. “Every historically documented tsunami pales in comparison to such a global impact.”
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This article was originally published by Live Science. Read the original article here.
