AN OXYGEN ISOTOPE TEMPERATURE RECORD OF THE HELL CREEK FORMATION OF NORTH DAKOTA/MONTANA AND ITS APPLICATION TO TURTLE PALEOECOLOGY ACROSS THE K-P BOUNDARY

Although the large-scale pattern of mass extinction due to catastrophic asteroid impacts at the Cretaceous-Paleogene boundary is well documented, there remains pervasive ambiguity regarding local scale patterns of faunal turnover. That is, it remains largely unclear why certain groups persist across the boundary, while others do not. Furthermore, terrestrial temperature records during the late Cretaceous mass extinction are poorly known, despite the potential utility of such records for paleoecological studies elucidating the driving forces behind observed extinction patterns. Here, a new oxygen isotope proxy temperature record derived from freshwater gar scales and turtle bone from the Hell Creek formation of North Dakota and Montana is presented and compared with faunal changes in corresponding localities across the K-P boundary, with particular focus on turtles.