The early Paleogene (~66-48 million years ago) was an important time in Earth’s history: It immediately followed the mass extinction of all dinosaurs (except birds), many modern groups of mammals first appeared, and the Paleocene-Eocene Thermal Maximum (a significant climate event) occurred. Knowledge of these events is mostly based on a well-dated and characterized North American stratigraphic record; a global perspective on these events is missing. This project will apply modern, high-precision, age-dating techniques to the sedimentological and mammal fossil records of Mongolia. These methods will allow the building of a critical framework for comparing the North American and Asian fossil records across this important time interval. New physical and digital collections of fossils and a pop-up traveling exhibition on Paleogene mammal evolution and climate will be created. Developing a modern chronostratigraphy and paleoenvironment reconstruction for the highly fossiliferous Naran Bulak and Gashato Formations in Mongolia is the goal of this project. Four geochronological methods will be used, including magneto- and chemo-stratigraphy and Ar/Ar and U-Pb geochronology. Age and correlation data will be combined with careful sedimentological and paleoenvironmental analysis. These methods will be used to precisely constrain this important fauna and permit precise correlations with other parts of Asia and with the North America record. This geochronologic focus will be couple