The devastating asteroid strike that killed off the dinosaurs may have triggered a powerful “mega-earthquake” that shook Earth for months on end.
66 million years ago a massive solar system body — now known as the Chicxulub asteroid — collided with Earth, excavating a massive 180 km (110 mile) wide impact crater in what would later become the Yucatan Peninsula.
This collision triggered a chain of cataclysmic events which, when combined with the devastation caused by the initial strike, wiped out 75 percent of all life on Earth.
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Now, fresh research that analyzed geological records from this traumatic period in our planet’s history, has revealed that the devastating impact may have triggered a “mega-earthquake” that lasted for weeks, or even months before subsiding.
The research was presented on October 9. at the Geological Society of America’s annual meeting by Hermann Bermúdez of Montclair State University – one of the scientists who worked on the study.
Back in 2014, Bermúdez discovered a series of minute glass spheres and shards, roughly 1 millimeter in size, buried among the sediment on Gorgonilla Island, which is located off the west coast of Colombia.
These tiny relics were formed on the day that the Chicxulub asteroid struck the surface. The impact threw vast quantities of molten material high into the atmosphere, which subsequently coalesced, cooled, and fell back to Earth as glassy balls and irregular shaped debris.
At the time the asteroid struck, the site Bermúdez had excavated was actually underwater. Despite the fact that it was located some 3,000 km (1,860 miles) from the impact site, the underwater landscape was deformed by the force of the event. Traces of this deformation — which extended 10 – 15 m (30 – 50 ft) underground — are still evident to this day.
Bermúdez and his co-researchers also documented faults, cracks, and evidence of a process called liquefaction — wherein water saturated sediments flow freely like water under the vibrating influence of an earthquake — in Mexico, and the United States.
According to a press release from the Geological Society of America (GSA) outlining the presentation, the earthquake which shook Earth in the wake of the extinction event was roughly 50,000 times more powerful than the magnitude 9.1 earthquake that devastated Sumatra in 2004.
The researchers found that the disruption caused by the shaking extended through the sediment layer from the point at which the asteroid struck, up to where the team found the tiny glass spheres on Gorgonilla Island.
The geological evidence shows that the super-quake must have endured for the weeks, or even months that it would have taken for the impact-ejected debris to descend through the atmosphere, and subsequently the ocean environment, to settle on the seabed.
Just above this layer, the team discovered the spores from ferns, which indicated that the environment had settled enough at this point to allow plant life to re-establish itself.
The damage wrought by the earthquake would have added to the devastation caused by the powerful tsunamis and atmospheric debris circulation brought on by the event.
NASA and its partners recently completed the world’s first planetary defence mission — the Double Asteroid Redirection Test (DART) — during which it crashed a spacecraft into the surface of a distant asteroid in an attempt to alter its orbital trajectory.
The agency hopes that this mission is the first step on the road to developing an effective strategy that could one day save our race — and all life on Earth — from the perils of another potentially devastating asteroid strike.
Anthony Wood is a freelance science writer for IGN
Image credit: Vadim Sadovski
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