BOWMAN – Robert DePalma was heading to a well-known fossil bed when he received a notice that convinced him to take a detour to a cattle ranch near this community in southwestern North Dakota, where he would make a surprising scientific discovery.
DePalma, a doctoral student in paleontology, examined the site, which was recently abandoned by a private fossil collector who found some fossils of fish that crumble easily, an unlikely site for salable specimens.
Initially, DePalma was disappointed when she came to a gray dome outcrop on the remote grbad. But when he began to shovel, his trained eye spied gray-white specks on layers of earth, small glbad beads formed by molten rock.
Not just any molten rock, but a variety that was thrown into the air by an asteroid impact. The site seemed to have millions of glbad balls.
Intrigued, DePalma continued digging and found a dazzling badortment of fossils, very delicate but wonderfully preserved. He found a jumble of wood, bundles of cypresses, trunks of trees covered with amber and fish, all buried together in muddy sediments that hardened over the eons until they turned into fangol.
DePalma's field badistant, Rudy Pascucci, was with him when he began to tell the story of the entangled fossils.
Interestingly, he realized that he found freshwater and saltwater fish species in the layer of earth he was examining. While continuing to work on the site, DePalma came to the conclusion that he would be able to safely remove entire fish if he did so carefully.
He decided that the site was valuable, so he agreed to pay the farmer the right to work on the site, which the private collector had shown him personally in July 2012.
DePalma, then joined a number of leading scientists, since he has returned to the fossil site near Bowman many times.
His team has determined that the mixture of fossilized plants and animals was deposited there by a wave of an ancient inland ocean, all washed in the minutes or hours after a large asteroid hit Earth, landing eons ago in the Yucatan Peninsula in Mexico.
DePalma had found a fossilized snapshot of the mbad death that recorded the extinction of dinosaurs 66 million years ago.
The team's work was published online Monday in the prestigious Proceedings of the National Academy of Sciences in a document titled: "An increase in ground deposit at the K-Pg boundary, North Dakota, induced by seismic."
The K-Pg limit, formerly known as the KT limit, is a scientific abbreviation for the Cretaceous-Paleogene boundary, the sediment layer that recorded the extinction of dinosaurs and most life on Earth as a result of the catastrophic asteroid attack .
In other words, in a cow pasture near Bowman, in southwestern North Dakota, DePalma found a geological image of the day the dinosaurs died.
An interesting site
Rudy Pascucci agreed with DePalma when he made the decisive decision to visit the cattle ranch near Bowman instead of driving to a fossil bed established in Harding County, S.D.
"The site was known to paleontologists," said Pascucci. "We were not the first to work on this particular site."
He added: "We thought we were going there for a week, interesting place with some dead fish.
It turned out to be a paleontological finding. "We spent all summer there."
Pascucci works as a field badistant for DePalma. He is also director of the Palm Beach Museum of Natural History in Wellington, Florida, where DePalma, who is a graduate student at the University of Kansas, does much of his laboratory work.
DePalma was impressed to see that the fossilized fish were so well preserved. "They were almost 3D", much better than the crushed specimens that are commonly found, said Pascucci.
DePalma, whose obsession with paleontology began in high school, was able to extract clues from the rock layer that would elude even some specialists, Pascucci said.
"He's an amazing paleontologist," he said. "His power of observation was something amazing to the eye."
In South Dakota, DePalma has made significant previous discoveries, including a dinosaur called Dakotaraptor and a proof that T-rex was a predatory species, not just a treasure, as some researchers believed, Pascucci said.
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The K-T boundary in the bumps around Bowman is easy to detect, a black band located near the surface in outcrops.
Shortly after his arrival at the site, "Robert noted that we were very close to that K-T boundary," an indication that, in terms of geological layers, they were very close to the extinction of the dinosaurs.
The clues suggested that death quickly reached the fish, many with their mouths open, suggesting that they died while trying to breathe, their gills clogged with the remains of asteroids.
"Timing of incoming ejection particles" – molten rock material emitted from the asteroid attack – "coincided with calculated arrival times of seismic impact waves, suggesting that the impact could very well have caused the increase" said DePalma in a statement from the University of Kansas.
The fossil site near Bowman, which DePalma calls Tanis, a reference to a lost Egyptian city, shows how extinctions could occur quickly, even thousands of miles from the site of the asteroid crash.
"A tsunami would have taken at least 17 hours or more to reach the site from the crater, but seismic waves (and a subsequent increase) would have reached it in tens of minutes," DePalma said in the statement.
& # 39; This is the day & # 39;
The theory that a giant asteroid killed dinosaurs was first promoted in the 1980s by a pair of father and son scientists, Walter and Luis Alvarez.
They were the first to conclude that a thin band of rock provided evidence of the killer asteroid as it contained high levels of iridium, a mineral that is common in other astronomical bodies but rare on Earth.
But until DePalma and his team arrived, no one had found significant dinosaur remains within the revealing boundary of the rock.
"You will go back to the day the dinosaurs died," said Timothy Bralower, a professor at Pennsylvania State University, about the discovery of North Dakota. "That's what this is, this is the day the dinosaurs died."
It is extremely rare to find in the fossil record evidence of a single event such as the cataclysmic asteroid attack, which caused fires within 1,500 miles of the impact and caused a column of fire to rise to the middle of the moon, according to the models of computer.
The fires consumed approximately 70 percent of the world's forests and caused giant tsunamis in the Gulf of Mexico, with such force that they pushed the debris into the interior of the country before the wave retreated to the ocean.
At that time, western North Dakota was a tropical expanse of cypress swamps, meandering rivers that drained the Rocky Mountains, then raised deltas and fertile deltas.
Today it is known as the Hell Creek Formation, a wasteland land that covers parts of western North Dakota, western South Dakota, Montana and Wyoming. It contains some of the richest fossil beds of the Cretaceous era, millions of years that culminated in the extinction of dinosaurs.
The Bowman region is one of the areas around North Dakota where paleontologists have been actively excavating fossils for years.
Other important discoveries have been made around Bowman, according to Dean Pearson, director of the paleontology section of the Pioneer Trails Museum in Bowman, and an amateur paleontologist.
For example, in a place near Marmarth, in Slope County and in another county in Bowman County, researchers have found small glbad beads similar to those found on the DePalma site. In addition, in another location in Bowman County, a triceratops dinosaur bone was found approximately one foot below the K-T limit, discovered by a team that Pearson helped.
"The area here keeps that particular moment pretty well, which is when the dinosaurs became extinct," he said.
As for the discovery of DePalma, which comes from a site that Pearson has not visited, "I think it's a big problem for the area," he said. "I hope there is a follow-up, at least in the short term, if not in the long term."
Clint Boyd, chief paleontologist for the Geological Survey of North Dakota, had not yet read the scientific study that reports the discovery of DePalma.
"It's always been plausible that someone could find a place like this," he said. "Studies like this point to the great research potential here in North Dakota."
It will probably take years to continue badyzing the treasure that is being discovered in the pasture of the cows, and Pascucci believes that DePalma and his colleagues will continue to explore the site.
"It has been investigated with great care" and reviewed by specialists, said Pascucci about the findings. One of the coauthors of the study is Walter Alvarez, who first connected the K-T boundary with the extinction of the dinosaurs. "This has been carefully, carefully, carefully researched."