KU team helps document death of dinosaurs
A new mass mortality site of the giant “raptor” dinosaur, Utahraptor was discovered and described from the Early Cretaceous (of east-central Utah) by James I. Kirkland, State Paleontologist of Utah with the Utah Geological Survey. Utahraptor was initially described by Kirkland in 1993 from literally a handful of bones. Utahraptor received fame as reality providing justification for Steven Spielberg’s oversized “Velociraptors” in his movie, Jurassic Park. The quicksand interpretation of this spectacular dinosaur deposit is published in the international journal Palaios by Kirkland and is co-authored with Edward Simpson of Kutztown University.
Additional authors include: Don DeBlieux (Utah Geological Survey), Scott Madson (Utah Geological Survey), Emily Bogner (undergraduate Kutztown University) and Neil Tibert (University of Mary Washington).
The site is on Utah State and Institutional Trust Lands high on Utahraptor Ridge north of Arches National Park. The 9-ton sandstone block was removed from the cliff face in December 2014 and contains many well-preserved skeletons representing variousaged Utahraptor dinosaurs ranging from small, probably several months old, juveniles, up to at least one fully grown adult that were trapped and died in “quick sand” deposit on the margin of an infilling Early Cretaceous lake. Features preserved in the rocks show the extent and the geometry of the water flowing up through the compacting sediments that generated the forces necessary to generate the quicksand. The dinosaurs were drawn to the spring possibly by trapped plant-eating dinosaurs or from thirst and were then stuck in the sandy quagmire.
This the first time such a quick sand mechanism has been proposed for a dinosaur mass mortality site. Other ancient mass mortality sites have been documented as a result of 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 the skeletons are carefully extracted from this massive block.
The great size of this block was necessitated by the high density of skeletons preserved within it. To quote UGS fossil preparator Don DeBlieux; “You couldn’t stick an ice pick into the mass without hitting a bone.” As a result the entire Utahraptor filled quagmire was collected intact. An engineering feat of remarkable skill thanks to the help of Cross Marine Projects and the design skills of Phil Policelli.
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 rests in the preparation lab at the North American Museum of Ancient Life at Thanksgiving Point in Lehi, Utah. Funding is being sought to properly study and extract the fossils from the quicksand block as a further test of our quicksand hypothesis and resulting in Utahraptor becoming one of the very best documented dromaeosaur (“raptor” dinosaur) in the world.