The proposed investigation of U-Pb dating of fluor-apatite conodont elements may provide a powerful geologic tool for linking biostratigraphic zones with absolute ages. The combination eliminates the need to interpolate boundary ages from absolute ages derived from sporadically distributed igneous rocks. This interpolation is one of the largest sources of error in current absolute geologic time scales. For the pilot study proposed for this planning grant, the PI will date the stage boundaries in the Early Permian, a time when the nomenclature and stratigraphic positions of stage boundaries are generally agreed upon, and for which the PI can obtain abundant conodonts. If successful, the PI will submit a major proposal to extend the approach into the Late Permian, a time when the stage boundaries and duration of stages are subject to constant debate. Resolution of the Late Permian stratigraphic controversies is of particular interest because the time period includes the most extensive Phanerozoic mass extinction, the lowest sea level stands, the end of the Kiaman Reversed Period, and very rapid apparent rates of change in a number of geochemical parameters. Success of this project will give the PI an important new tool to enhance her existing research, which focuses on the interpretation of global climate change recorded by isotopic variations preserved in marine organisms.