1. Applying detrital zircon geochronology to identify variations in sedimentary provenance of the Cretaceous Straight Cliffs Formation, Southern Utah Tyler Szwarc Advisor: Cari Johnson

2. COUT NMAZ Late Cretaceous (~85 Ma) http://www2.nau.edu/rcb7/ColoPlatCret_PictCliffs.jpg

3. Previous Research Sedimentary provenance changes across sequence boundaries Lawton et al., 2003

4. Project Overview Infer sedimentary provenance of John Henry Member, Straight Cliffs Formation Use detrital zircon ages from ~20 sandstone samples as “tracers” Look for changes in provenance through time and space

5. What is a Detrital Zircon? Silicate mineral that forms in felsic igneous melts Incorporates radioactive uranium into the crystal U/Pb ratio provides crystallization age “detrital” implies the zircon has been transported from origin

8. COUT NMAZ Late Cretaceous (~80 Ma) http://www2.nau.edu/rcb7/ColoPlatCret_PictCliffs.jpg Sevier Fold/Thrust Belt Mogollon Highlands UT CO Dickinson and Gehrels, 2008

9. Importance Provenance studies help determine spatial extent of sandstones Better understand the nature of sequence boundaries in fluvial strata Obtain a better understanding of foreland basin evolution

10. References Blakey, Ron, 2011, Paleogeography of the Colorado Plateau and Vicinity, http://www2.nau.edu/rcb7/ColoPlatPalgeog.html Dickinson, W., and Gehrels, G., 2008. Sediment delivery to the Cordilleran Foreland Basin: Insights from U-Pb ages of detrital zircons in upper Jurassic and Cretaceous strata of the Colorado Plateau. American Journal of Science, vol. 308, December 2008, P. 1041 – 1082. Lawton, T., Polluck, S., and Robinson, R., 2003. Integrating sandstone petrology and nonmarine sequence stratigraphy: Application to the Late Cretaceous fluvial systems of southwestern Utah, U.S.A., Journal of Sedimentary Research, vol. 73, No. 3, May 2003, P. 389 – 406.