Scientists Find Evidence of Mile-high Tsunami Generated By Dino-killing Asteroid (sciencemag.org) 21
Slashdot reader sciencehabit shares news from Science magazine:
When a giant space rock struck the waters near Mexico's Yucatán Peninsula 66 million years ago, it sent up a blanket of dust that blotted out the Sun for years, sending temperatures plummeting and killing off the dinosaurs. The impact also generated a tsunami in the Gulf of Mexico that some modelers believe sent an initial tidal wave up to 1500 meters (or nearly 1 mile) high crashing into North America, one that was followed by smaller pulses.
Now, for the first time, scientists have discovered fossilized megaripples from this tsunami buried in sediments in what is now central Louisiana.
"It's great to actually have evidence of something that has been theorized for a really long time," says Sean Gulick, a geophysicist at the University of Texas, Austin. Gulick was not involved in the work, but he co-led a campaign in 2016 to drill down to the remains of the impact crater, called Chicxulub... Cores from the 2016 drilling expedition helped explain how the impact crater was formed and charted the disappearance and recovery of Earth's life. In 2019, researchers reported the discovery of a fossil site in North Dakota, 3000 kilometers north of Chicxulub, that they say records the hours after the impact and includes debris swept inland from the tsunami.
"We have small pieces of the puzzle that keep getting added in," says Alfio Alessandro Chiarenza, a paleontologist at the University of Vigo who was not involved with the new study. "Now this research is another one, giving more evidence of a cataclysmic tsunami that probably inundated [everything] for thousands of miles."
Now, for the first time, scientists have discovered fossilized megaripples from this tsunami buried in sediments in what is now central Louisiana.
"It's great to actually have evidence of something that has been theorized for a really long time," says Sean Gulick, a geophysicist at the University of Texas, Austin. Gulick was not involved in the work, but he co-led a campaign in 2016 to drill down to the remains of the impact crater, called Chicxulub... Cores from the 2016 drilling expedition helped explain how the impact crater was formed and charted the disappearance and recovery of Earth's life. In 2019, researchers reported the discovery of a fossil site in North Dakota, 3000 kilometers north of Chicxulub, that they say records the hours after the impact and includes debris swept inland from the tsunami.
"We have small pieces of the puzzle that keep getting added in," says Alfio Alessandro Chiarenza, a paleontologist at the University of Vigo who was not involved with the new study. "Now this research is another one, giving more evidence of a cataclysmic tsunami that probably inundated [everything] for thousands of miles."
just in case it happens again (Score:4, Interesting)
p.s. asking for a friend!
Re:just in case it happens again (Score:4, Informative)
It would depend on where the asteroid strikes. Pike's Peak is ~14,000 feet (4,267 meters) tall, and there are many other peaks in the Rockies which are above 2 km in height. However, if an asteroid hits anywhere nearby, even without the mile high tsunami, it wouldn't make a difference being that high up. You'd be vaporized or smashed to bits by the concussive force.
For reference, the Matterhorn is 4,478 meters tall, only slightly taller than Pike's Peak.
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indeed. If you are close, you are dead. If you are further away, the tsunami will be the least of your problems.
The main concern will be surviving the year-long blackout of the sun, and the collapse of social order. You will need a food cache and the ability to defend it.
Re:just in case it happens again (Score:4, Interesting)
We'd see six-mile diameter asteroid coming for a long time beforehand though; years. Amazing things can be done in decade or more when money is no object.
Re:just in case it happens again (Score:4, Informative)
iggymanz confidently stated:
We'd see six-mile diameter asteroid coming for a long time beforehand though; years. Amazing things can be done in decade or more when money is no object.
Not necessarily [wikipedia.org].
We keep a pretty good watch on stuff in the plane of the ecliptic. Not so much on stuff "Comin' in to London from over the Pole ..."
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that wasn't an asteroid, not part of solar system, not having albedo of one, and it was tiny, only could take out city.
Not a case for what we're worried about.
Re: just in case it happens again (Score:2)
Re:just in case it happens again (Score:5, Informative)
Actually, there's good modelling that suggests what killed nearly everything on the planet was the sky becoming incandescent from all of the debris raining down and burning up in the atmosphere. Nearly all life was roasted to death within a few hours after the impact.
It was not a good day to be on our planet, no matter where you hid.
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Re:just in case it happens again (Score:5, Informative)
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That's for a static sea level rise. Tsunamis' heights depend on the effects of drag on the ocean floor and distance from the origin.
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If you get hit by the tsunami, you're one of the lucky ones. Better than being almost anywhere else on the planet and getting roasted alive by the pizza oven temperatures generated by reentering suborbital debris.
Screw it (Score:5, Interesting)
Re: just in case it happens again (Score:2)
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Always the random slashdotter not bothering to look at TFA, certain that their vast knowledge of nothing gives them supreme authority over everything. You should at least do this as an AC.
You gets a 1500 meter wall of water not as any normal wave, or even a normal tsuanmia, but simply because all of the water displaced laterally all at once by the impact. Just look at the picture in the TFA is reading comprehension is not your thing.
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There would be differences in elevations due to uplift such as the Rocky Mountains and the Appalachian Mountains which have affected the terrain since then. Many areas of the Appalachian chain had been eroded flat and then were re-uplifted 20 million years ago. There was the Great Interior Seaway which split North America into two main landmasses.
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The wave will very quickly diminish in height after it breaks, so it is more important to be far from the shoreline than higher than the top of the wave.
This can easily be seen if you go to the beach when there are big waves. You can easily sit somewhere so that the tops of the waves are above the horizon (and thus above your head) but the water does not even reach you.
Scary to think about. (Score:2)
Did the New Orleans jazz scene manage to survive that one?
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