Salt Lake City (Sept. 22, 2016) – A team of scientists led by James I. Kirkland, state paleontologist with the Utah Geological Survey (UGS), have published the initial results of a new study describing a huge Utah fossil block documented as the world’s first reported dinosaur death trap attributed to quicksand.
Researchers discovered the Utahraptor mass-grave site on Utah state trust lands north of Arches National Park and high up on Utahraptor Ridge (officially named in 2015). Utahraptor received fame as the real-life basis for Steven Spielberg’s oversized “Velociraptors” in his movie, Jurassic Park.
At Utahraptor Ridge, scientists removed the nine-ton sandstone block from the steep slope in December 2014. The mega-block contains many well-preserved skeletons representing various-aged Utahraptors ranging from small, probably several months old, juveniles to at least one fully grown adult. These dinosaurs were trapped and died in a quicksand type of deposit on the margin of an ancient lake over 100 million years ago, during the Early Cretaceous.
Features preserved in the rocks show that water flowed up through compacting sediments and generated the forces necessary to create quicksand. Thirst or hunger for previously trapped plant-eating dinosaurs may have drawn the raptors into the sandy quagmire. This is the first time paleontologists have proposed such a quicksand mechanism for a dinosaur mass-mortality site. Other ancient mass-mortality sites have been attributed to drought, poisoning, floods, hurricanes, and trapping in caves or sinkholes. Observations at modern quicksand sites, such as the Colorado River delta at Lake Powell, support this hypothesis, which will be further tested as researchers carefully extract more skeletons from this massive block.
The high density of skeletons within the block required that it be collected as a single piece. According to UGS paleontologist Don DeBlieux, “You couldn’t stick an ice pick into the mass without hitting a bone.” As a result the scientists collected the entire Utahraptor-filled quagmire intact. Collection and transport of the this giant block was an engineering feat made possible with the design skills of aerospace engineer Phil Policelli and the help of Cross Marine Projects Company.
The authors liken the paleontological importance of this giant mass of skeletons to archaeologists collecting King Tut’s tomb intact, so that it could be opened carefully at the museum. This scientific treasure currently rests in the preparation lab at the Museum of Ancient Life at Thanksgiving Point in Lehi, Utah. Funding is being sought to properly extract and study the skeletons from the block, potentially making Utahraptor the best known dinosaur of its kind.
The study was published in the September issue of the international journal Palaios and is co-authored by Edward Simpson of Kutztown University. Additional authors include Don DeBlieux (UGS), Scott Madson (UGS), Emily Bogner (Kutztown University), and Neil Tibert (University of Mary Washington).