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Scientists have created a new map of “mega ripples” on the seafloor caused by the Chicxulub asteroid impact that wiped out the dinosaurs, revealing further the events that led to the devastating mass extinction event.
The study, published in the journal Marine Geology, unravels the forces generated by the space rock, whose impact triggered a global tsunami at the end of the Cretaceous era 66 million years ago.
Researchers found that the impact triggered mega ripples on the seafloor, sometimes as high as a five-story building, extending across a much larger area than previously thought.
They say the new findings may also lead to a better understanding of the effects and dangers of tsunamis and such giant waves triggered by space rock impacts.
Previous studies have found that the nearly 10km-wide asteroid that slammed into the water near what is now Mexico’s Yucatan peninsula triggered a massive tsunami unlike anything ever documented.
Scientists also found compelling evidence of unique geographical formations underground in Louisiana – at depths up to 1.5km (5,000ft) below – created by these massive waves.
These mega ripples, which are huge fossilised ripples, were created by a massive influx of water, which then receded, they found.
Now, researchers have created a 3-dimensional map of these fossil ripples spanning an area of over 2,400sqkm (900sqm), helping model the direction and impact of the massive tsunami that caused these formations.
Scientists found that the long, asymmetrical sides of these fossil ripples point south-southeast, revealing the direction of the tsunami’s source at the tip of Mexico’s Yucatán Peninsula.
These megaripples also appear to have formed differently compared to how conventional sea waves cause ripples on beaches by moving sand particles.
In the case of these megaripples, a massive earthquake following the impact event seems to have first fluidised a layer of sediment, which was then shaped into waveforms by high-speed tsunami waves.
“We propose that the megaripples were formed in these muds by fluid traction of the tsunami in much the same way that water waves are formed by the traction of wind and the forms persisted in the muds as the tsunami waned,” scientists wrote.
This new map of the megaripples can help predict the impact of future tsunamis, and to better understand the dinosaur extinction event, scientists say.
