Geologic mapping studies are underway to help define the geologic framework for integrated ecosystem and climate change research in the Greater Platte River Basins, an ecoregion being targeted for collaborative observation and research by the Climate Effects Network (CEN) of the U.S. Geological Survey (USGS) Global Change Program. Geologic mapping and associated geochronological research provide information about physical and chemical properties, distribution, age, origin, and stratigraphic relations of surficial geologic deposits for reconstructing geologic and hydrologic history and for recognizing geomorphic response to climate change that is recorded in the geologic record.