Paleontologists working in the northern United States have discovered one of the most remarkable collections of fossils ever discovered, from the day a giant asteroid struck a shallow sea on primordial Earth 66 million years ago.
Immediately after the impact of the asteroid, an unimaginable flood swept the planet. Earth trembled with severe earthquakes that had never been felt before. Although the asteroid has landed in what is now Mexico, it was so devastating that the effects were felt thousands of miles away due to the tumultuous crash of Earth.
The infernal fire and vitreous and tiny granules – tektitas – rained on the ground before dust and soot clouded the atmosphere. The sun is gone. As a result, it is believed that approximately 75% of all living creatures and most dinosaurs have been extinct.
The tektites rained on the fish, protested against the trees and struck the dinosaurs. Life perished quickly, and the bodies of the dead settled on the ground, glass beads still wrapped in their bones. Now these skeletons are being plucked from Earth – and they are revealing, for the first time, exactly what happened after the asteroid hit.
In an article to be published in the PNAS at 9am on Monday, Robert A. DePalma and a team of paleontologists detail the huge fossil accumulation found in the geological formation of Hell Creek, which encompasses North Dakota, South Dakota, Wyoming and Montana. Together, a fascinating account of Douglas Preston appeared on March 29 in The New Yorker detailing DePalma's discoveries and seven years on the spot, which the paleontologist christened "Tanis" after the ancient Egyptian city in Raiders of the Lost Ark.
To understand the importance of the discoveries in Tanis, one must understand the importance of the "Cretaceous-Paleogene (K-Pg) boundary", a layer of rock buried in the Earth that delineates the end of the Cretaceous period and the beginning of the period. Paleogene – the age we live in today.
It is believed that this limit was formed when the giant asteroid hit the Earth, depositing a dark layer of dust inside the Earth. For years, scientists have investigated the region in search of fossils, but have not found bones that rested near the border. With no fossils near the border, some scientists have suggested that dinosaurs could be in decline long before the collision of cataclysmic asteroids.
But at Hell Creek, DePalma found fossils of fish, seeds, dinosaurs and, they say, even mammals' burrows beneath that dark layer near the border.
The hypothesis is that, within hours of the asteroid's impact, a huge wave of water invaded the area, leveling everything in its path. The tektitos that fell around the impact crater were swept thousands of kilometers to the north and ended up housed in the gills of fish found in the place. The findings provide surprising new evidence of how Earth responded in the moments after the planet's disruption to oblivion.
"This solves the question of whether the dinosaurs were extinct at exactly that level or if they had declined before," Jan Smit, a paleontologist and co-author of the article, told The New Yorker. "And this is the first time we see direct victims."
Ultimately, the entangled cemetery provides a snapshot of the day the Earth shook – and potentially the last day the dinosaurs roamed the Earth.