Jon Smith is an associate scientist with the Kansas Geological Survey and has been researching, among other things, the ichnofossils at Ashfall. “Some of the layers have dog footprints on them,” Smith said. “I think at Ashfall you can definitely make a strong case that [these] dogs were digging down through the ash and eating really rotten meat.” Tellingly, they left coprolites—fossilized feces—and regurgitates—fossilized vomit. “It was coming out of one end,” he quipped, “maybe both.”
All of this, he added, provides evidence that bone-crushing dogs existed there, despite the lack of body fossils. Smith refers to these trace fossils, or ichnofossils, as the “hidden biodiversity” of the site. Other ichnofossils point to tinier members of the ecosystem: small mammal and arthropod burrows, and, surprisingly, the extensive underground homes of ancient ants, discovered thanks to Smith, who recognized what they were.
“All of these add up to a once-in-a-lifetime deposit,” Tucker said, explaining that other sites tend to be an “accumulation of bones over hundreds or thousands of years.” At Ashfall, it is “an instantaneous capture of what the landscape looked like.”
At least the landscape in the waterhole. The number of animals uncovered in the ash bed so far is phenomenal, but Otto pondered the potential number of animals that didn’t survive fossilization. Consider, he said, what happened when the waterhole was almost completely full of ash. “If an animal lay down and died at that time, its bones would have been close enough to the surface that the bones would have [eventually] deteriorated instead of having been preserved. So there probably were thousands and thousands of rhinos and horses and camels that died out in the open landscape away from the waterhole.”
Given the size of the eruption and the sheer amount and distance the ash fell, one might wonder why another similar site hasn’t been found anywhere else. Otto said that scientists have asked this very question. “This very same thing must have happened across the upper Great Plains—South Dakota, Nebraska, Kansas,” he noted. Volcanic ash has been found in at least a dozen other locations throughout Nebraska, but all of them are only a foot thick. The layer of ash would need to be at least 8 feet or so to indicate the former presence of a waterhole.
Otto feels it’s only a matter of time until we find similar sites, especially “as erosion continues to wear away at the local sedimentary rock. Some day, a thick exposure of ash is going to erode out,” revealing another remarkable fossil site.
Decades of influence
The wealth of information this site provides can’t be overstated, nor can its impact on those who have studied it. Otto went from excavating the site as a student in the '70s to becoming the park’s superintendent for over 30 years. Tucker’s passion for Ashfall sparked a career in paleontology. Mosel, who reluctantly answered an ad for a “Clerk/Typist” at Ashfall 33 years ago, said, “I have loved every minute of it. It has been the best job.” The culture within Ashfall encouraged informal learning, Mosel said, a setting in which she thrived.
Rachel Short, who interned at Ashfall during the summers of 2009 and 2010, said it helped shape her career. Prior to college, she didn’t realize paleontology could be a profession—now she’s an assistant professor in the Department of Natural Resource Management at South Dakota State University. At Ashfall, she not only learned a great deal about fossil excavation but also about interacting with the public and effective science communication.
“I spent a lot of years being asked, ‘Why? Why do we care? Why are you doing this?’” she recalled. These types of questions are one of the reasons she says she works so hard to articulate the meaning of her research. “I think as paleontologists or scientists, we have a responsibility to tell people why we care and what we’re getting out of it.”
Approximately a decade after her work at Ashfall, she discovered another rhino species at the Gray Fossil Site in Tennessee. “I really struggled with ‘how do we make the rhinos mean something?’” she said. To find that meaning, she’s focusing on how the physical differences between the species are a product of their different diets and environments and whether those same mechanisms shape species today.
For all of its phenomenal fossil preservation and the profound impact it has had on those who have worked there, the park is still a bit of a hidden gem. “The one thing that amazes me,” Tucker admitted, “is how many people in Nebraska don’t even know this exists.”
Promoted Comments