THE YUCATÁN'S CHICXULUB CRATER AND ITS CONNECTION TO THE DINOSAUR EXTINCTION

 

Chicxulub Crater Reproduction

For 170 million years during the Cretaceous Period, a time when oceans formed as land shifted and broke out of one big supercontinent into smaller ones, dinosaurs ruled the world. Meanwhile, an asteroid was hurtling towards planet Earth after its misguided journey around the sun.

The most consequential outcome of this impact caused a cataclysmic event known as the fifth extinction, wiping out roughly 80 percent of all animal species, including non-avian dinosaurs. But what really happened when the asteroid collided with Earth?

Hidden below the waters of the Gulf of Mexico, the Chicxulub crater marks the impact site where the asteroid struck our planet 66 million years ago. 

“The asteroid was moving astonishingly quickly,” according to Professor Gareth Collings of Planetary Science at Imperial College in London. “Probably around 12.5 miles per second when it struck. That’s about 100 times the speed of a jumbo jet.” 

SIZE MATTERS

By studying both Chicxulub and worldwide geology, scientists have pieced together what happened that fateful day and in the years following. Larger than the height Mount Everest reaches into the atmosphere, the mountain-sized asteroid slammed into Earth. It unleashed the equivalent energy of billions of nuclear weapons all at once. It vaporized the Gulf of Mexico. Bedrock melted into seething white flames at tens of thousands of degrees Celsius, and it created a hole 25 kilometers deep and nearly 120 miles wide.

The crater is a fairly recent discovery, first discovered in 1978 by geophysicist Glen Penfield who worked for Pemex, Mexico's state-owned oil agency. While searching for oil, his crew used a magnet-o-meter as they flew above the Gulf. That's when Penfield saw the outline of a perfect semi-circle in the water below, where the ground had been vaporized in a split second so long ago.

His device indicated to him and geophysicist Antonio Camargo Zanoguera that a magnetic field different from volcanic terrain existed there. The saucer shaped underground structure was ten times the size of any volcano. The two men agreed, according to Smithsonian Magazine, that it could not be the result of a volcano and most probably was that of an impact crater.

SPECIES COLLAPSE

Because of the impact, Earth's water supplies were poisoned and 75 percent of species vanished. The 25 percent that survived were pushed to the brink of extinction and anything larger than a raccoon perished. It would take 30,000 years for life to stabilize.

After Penfield's initial fly-over, Luis and Walter Alvarez (father and son) discovered a thin layer of iridium in a geological record marking the ending of the Cretaceous Period across the entire world. Iridium is more prevalent in comets and asteroids than on earth. 

The scientists theorized the impact led to global fires, smoke, and dust clouds that blocked out the sun, cooling the planet and preventing photosynthesis. They hypothesized that the crater might be the Cretaceous-Tertiary Mass Extinction event, commonly known as the K-T impact site.

MORE SCIENTISTS CLOCK IN

Soon after that, Allen Hildebrand, Ph.D. in Planetary Sciences from University of Arizona, worked with the Alvarez team and they published controversial articles suggesting that an impact from a large asteroid caused the mass extinction at the end of the Cretaceous Period. The site was determined to be at Chicxulub, and came to be known as the K-T event. 

In 1990 Adriana Ocampo, a planetary scientist from NASA, was using satellite images to map water resources in the Yucatan Peninsula. Along with her former husband, Dr. KEvin Pope, they discovered a semi-circular ring of cenotes, also known as sinkholes, that she recognized as related to the crater. They hypothesized the crater might be the K-T event site, publishing their findings in the journal Nature in 1991.

Adriana Campo (Photo YucatánTimes.

Ocampo has visited the Yucatán Peninsula numerous times since her discoveries, but few were aware of the importance of the place, she was quoted as saying in an interview in Yucatán Magazine. 

WORLD HERITAGE WORTHY?

"It should be preserved as a world heritage site," she said. Though not yet world heritage worthy, the Chicxulub Crater Science Museum south of Progreso is a stunning nod to the asteroid that literally shook our world 66 million years ago and created a new pecking order by destroying the dinosaurs.

Ocampo began connecting the dots back in 1988 when she attended a scientific conference in Acapulco as a young scientist. Though she’d studied with legendary pioneering astro-geologist Eugene Shoemaker, she gives Houston Chronicle journalist Carlos Byars credit as the first person to connect the Yucatán ring to the Alvarez father-son asteroid theory. 

Byars had shared his theory with Alan Hildebrand who then approached Penfield who'd flown over the Gulf for Pemex Oil in 1978. The two scientists determined the crater wasn't a volcano but an asteroid impact.

LAIDBACK SPOT

Chicxulub Puerto and Chicxulub Pueblo, the nearest pueblos, are laid back communities made famous because of the asteroid impact. But even the Crater Science Museum, part of the research complex in Yucatán Science and Technology Center, is miles away from the towns. 

Crater Science Museum, Chixculub.

The park, inaugurated in the past couple years, was closed during the pandemic. Now on what’s called the Jurassic Trail, it’s gained steam on social media and is growing in popularity.

The museum welcomes one to the world of yesteryear. Through its exhibits it shows how humans emerged at the top of the food chain after the astroid extinguished the dinosaurs. With no competition, here we are. So—loaded question—how are we doing?