December 4, 2022
The asteroid that killed the dinosaurs drove 100 meters of a tsunami thousands of kilometers

The asteroid that killed the dinosaurs drove 100 meters of a tsunami thousands of kilometers

when Chicxulub impact meteor hit the planet, 66 million years ago, a tsunami of gigantic proportions formed. Now, scientists are studying what this phenomenon would be like, collecting samples in the seas and conducting simulations of the first minutes after the collision, which occurred near the Yucatan Peninsula, in Mexico, and the effects that followed.

According to scientists, the giant wave was powerful enough to stir up ocean basins on about half of the planet, leaving a hole in the sedimentary records or mixing ancient sediments. For the study, boundary sedimentary areas were analyzed, i.e. places where marine sediments were deposited before or shortly after the impact and K-Pg (Cretaceous-Paleogene) extinction, observable even with the naked eye due to the difference in iridium generated by the asteroid.

Sediments, oceans and tsunamis

It is estimated that the energy tsunami Because of the impact it was 30,000 times greater than the 2004 Indian Ocean tsunami, which killed 23,000 people and was one of the largest waves of the modern era. 66 million years ago, the tsunami was supposed to reach the North Atlantic Ocean, passing through the Central American Channel (which separated the Americas at that time) and the South Pacific.

In these areas, the sea current probably exceeded 20 cm per second, which is enough to erode fine sediments from the sea floor. In the South Atlantic, the North Pacific, the Indian Ocean, and the Mediterranean at present, the effects of the tsunami did not appear as strong, according to simulations – no more than 20 cm / sec.

The study analyzed records from 164 sedimentary marine boundary zones, and collected useful information from 120 of them. In the most affected areas, the boundary of K-Pg is less pronounced: in New Zealand, more than 12,000 km from the impact, the sediments are patchy and strongly inverted, which is consistent with the expected tsunami course. In the Indian Ocean and the Mediterranean, the boundaries are clearer and more complete, which proves that they were rescued from the influences.

Watch the simulation video:

Based on other studies, a Asteroid 14 km in diameter, at a speed of 12 km / s. In the simulation, lightning struck a granitic crust covered with dense sediments in shallow ocean waters, creating a crater about 100 km wide and ejecting dense clouds of soot and dust into the atmosphere.

Two and a half minutes after the collision, a curtain of material pushed a wall of water away from the impact, forming a short-lived wave 4.5 kilometers high, and scattered after the shells fell back to the ground. In the next 10 minutes – and 220 km of collision – A tsunami 1.5 km began to spread out in a ring, outward and in all directions. The methods and models that were used Currently predicting deep tsunami.

Two universal models with different formulas gave almost identical results, which indicates the completeness, reliability and consistency of the data even in sections with incomplete data. Continuing the results, the team estimated that one hour after the impact, the tsunami had already spread out of the Gulf of Mexico into the North Atlantic.

About 4 hours after the impact, the waves had passed through the Central American Channel, reaching the Pacific Ocean. After 24 hours, the waves had crossed most of the Pacific Ocean to the east and most of the Atlantic Ocean to the west, entering the Indian Ocean on both sides. Within 48 hours, the tsunami would have reached most of the world’s coasts.

The study did not assess the level of coastal flooding caused by the tsunami, which should be done in a future survey, already planned. However, the models indicated the size of some waves: in the Gulf of Mexico, they could have reached 100 meters in height, and more than 10 meters in the North Atlantic and in parts of the Pacific Ocean, on the coast of South America. Upon reaching the coastal region, it would have increased, in a phenomenon called wave ulceration. In these areas, the velocity may reach 20 m/s.

source: ancestor AGU