Two massive asteroids may have killed the dinosaurs, not just one

Beneath the vast waters of the Atlantic Ocean lies a secret that’s been waiting to be told. Scientists have revealed images of an asteroid impact crater buried 300 meters under the ocean floor, shedding new light on Earth’s distant past.

The person behind this remarkable find is Dr. Uisdean Nicholson, a geologist from Heriot-Watt University who has dedicated years to studying the Earth’s hidden structures.

While examining the seabed off the coast of Guinea in West Africa, Nicholson and his team spotted an 8.5-mile-wide depression that piqued their curiosity.

His keen eye led to the discovery of the Nadir Crater, a silent witness to a colossal event from 66 million years ago.

3D imaging of Nadir asteroid crater

High-resolution, 3D seismic data provided by TGS, a global geophysical company, confirmed their suspicions.

The data proved that an asteroid, estimated to be between 1,476 and 1,640 feet wide, slammed into Earth at the end of the Cretaceous period.

The new images paint a picture of the catastrophic event.

“We can tell it came from about 20–40 degrees to the northeast, because of spiraling thrust-generated ridges surrounding the crater’s central peak — those are only formed following a low-angle oblique impact,” Dr. Nicholson explained.

“And we think it would have hit Earth at about 12 miles per second, or 45,000 miles per hour, although we still need to confirm this with a new set of impact models.”

What happened after the impact

Using the seismic data, the scientists reconstructed the immediate aftermath of the collision.

They observed the formation of an initial bowl-shaped crater, rocks turning into a fluid-like state and flowing upward, and a damage zone covering thousands of square miles.

An enormous tsunami, over 2,600 feet high, would have raced across the Atlantic as a result.

“There are around 20 confirmed marine craters worldwide, and none of them has been captured in anything close to this level of detail. It’s exquisite,” said Dr. Nicholson.

He likened the advancement in imaging to the evolution of ultrasounds, saying, “We’ve gone from 2D, fuzzy imaging to amazing high-resolution imaging of the Nadir Crater.”

Echoes of the dinosaur-killing impact

Interestingly, the Nadir Crater is the same age as the 125-mile-wide Chicxulub impact crater in Mexico, which is widely believed to have led to the extinction of the dinosaurs.

This raises questions about whether Earth was struck by multiple asteroids around the same time.

The team isn’t stopping at images. “We’ve applied to IODP3, which is a new international drilling program, to drill into the seabed and recover cores from the crater,” Dr. Nicholson shared.

“These will give us more information about the shock pressures experienced during impact and the precise age and sequence of events that occurred after this event.”

Asteroid crater insights

Collaborators are buzzing with excitement.

“3D seismic images of a fully preserved impact crater are a fantastic research opportunity that can allow us to consider how impact processes and craters scale with the size of the impactor both for understanding the evolution of the Earth and other worlds,” Dr. Sean Gulick from the University of Texas at Austin noted.

“We see pristine impact craters on airless bodies like the moon, but don’t have subsurface structural information,” Dr. Veronica Bray of the University of Arizona added.

“On the Earth, that is reversed: We have structural data from seismics, field mapping and drill cores, but the craters are usually very eroded at the surface. The new 3D seismic imaging of Nadir gives us both. It’s a startlingly good look at an impact crater!”

Asteroid threats today: The case of Bennu

While ancient impacts are fascinating, they also serve as a reminder of potential dangers lurking in space.

The asteroid Bennu, roughly 1,300 feet in diameter, is considered the most hazardous object in near-Earth orbit.

According to NASA scientists, its total impact probability through the year 2300 is about 1 in 1,750 (or 0.057%).

They’ve also pinpointed September 24, 2182, as the most significant single date for a potential impact, with a probability of 1 in 2,700 (or about 0.037%).

It’s a sobering thought that events like the one that created the Nadir Crater could happen again.

Preparing for the future by studying the past

Dr. Nicholson pointed out, “The closest humans have come to seeing something like this is the 1908 Tunguska event, when a 50-meter asteroid entered Earth’s atmosphere and exploded in the skies above Siberia.”

The data from the Nadir Crater offers an unprecedented chance to study impact craters in detail.

“The new 3D seismic data across the whole Nadir Crater is an unprecedented opportunity to test impact crater hypotheses, develop new models of crater formation in the marine environment and understand the consequences of such an event,” he said.

This discovery doesn’t just peel back layers of sediment, it also peels back layers of time. By exploring the Nadir Crater, scientists hope to unlock secrets about Earth’s past and better prepare for future asteroid encounters.

The full study was published in the journal Communications Earth & Environment.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–