“Finding a dinosaur bone in a core is like hitting a hole in one from the moon.” That was the way Denver Museum of Nature & Science curator of geology James Hagadorn described the odds of the museum’s newest fossil discovery a hockey-puck-sized vertebra discovered not in some far-off desert, but under the museum parking lot, 750 feet down. This was not a planned paleontological dig, but a geothermal borehole drilled to test for renewable heat, so the find is both unexpected and uniquely fortunate.
The engineering feat here is as attractive as the fossil itself. Modern geothermal drilling for heating systems involves sinking slender, deep boreholes typically less than five centimeters in diameter through sediment and rock layers. These bores, as well as draining heat out of the planet, also give continuous core samples, de facto cylindrical time capsules that hold a record of early settings. At this location, the center not only found a dinosaur bone but also fossilized plants, giving a glimpse into the swampy, green Denver of the Late Cretaceous, around 67.5 million years ago, when duck-billed dinosaurs and their kin inhabited a more Louisiana-like environment than semi-desert Front Range today.
Patrick O’Connor, the museum’s curator of vertebrate paleontology, described, “This animal was living in what was probably a swampy environment that would have been heavily vegetated at the time.” The find is currently the deepest and most ancient dinosaur fossil ever discovered in Denver, a distinction from previous findings in the city, which are surface finds of Tyrannosaurus rex and triceratops-type fossils.
The sheer impossibility of discovering a fossil in this incredibly restricted borehole cannot be overstressed. As Hagadorn put it, “It’s like winning the Willy Wonka factory. It’s incredible, it’s super rare.” Museum officials report that just two similar discoveries have ever been made known from borehole cores anywhere globally and never before under a dinosaur museum. The fossil’s morphology suggests it belonged to a small, plant-eating dinosaur, possibly a duck-billed hadrosaur or a thescelosaurus, though the exact species remains uncertain.
This Denver find recalls other spectacular instances when core sampling has paid off with surprising paleontological finds. In East Africa, the Olorgesailie Drilling Project obtained a 139-meter sediment core from the Koora basin that included a one-million-year environmental record and correlated faunal changes with early human development. Similarly, deep-sea research vessels like the Joides Resolution have drilled into the Mediterranean seafloor to obtain fossil marine organisms and climatic records illuminating Earth’s ancient history.
The Denver Museum’s borehole find is a testament both to the power of modern coring techniques and the value of interdisciplinary science. The world of engineers and energy planners that follows geothermal drilling can suddenly converge with paleontology and geology to deliver findings that redefine our understanding of local and global history. As Hagadorn pondered the situation, “That’s like finding a diamond deposit under the world’s largest gem store or an archeological site buried underneath the parking lot of an archeological museum.”
Even with the excitement, no proposals to excavate further beneath the museum parking lot practical priorities like parking take precedence over paleontological passion. But the fossil, since put on display, is a tangible testament that layers of geology beneath our feet still hold their secrets, to be revealed by an alliance of technology, wonder, and serendipity.
