While the Rocky Mountains were forming across the foreland of the US Cordillera, a series of lakes formed between the ranges. These lakes accumulated thick fossil-rich packages of sedimentary strata known as the Green River Formation. In this talk, Dr. Smith will explore how geochronology of interbedded volcanic ash beds within these deposits allows for the reconstruction of the ancient landscapes, rivers and lakes, and the sorts of tectonic processes that may have been responsible for these changes. Dr. Michael Elliot Smith is an Associate Professor of stratigraphy at Northern Arizona University. His research uses a broad swath of stratigraphic tools to better understand the evolution of Earth's ancient landscapes, and what these landscapes can tell us about its tectonic evolution. Geology Talks are in partnership with