Joint 118th Annual Cordilleran/72nd Annual Rocky Mountain Section Meeting - 2022

Paper No. 9-16
Presentation Time: 8:30 AM-6:00 PM


RICH, Adelaide, Department of Geosciences, Southern Utah University, 351 W University Blvd, Cedar City, UT 84720 and SHIMER, Grant, Department of Geociences, Southern Utah University, 351 W University Blvd, Cedar City, UT 84720

The sandstones and mudstones of the Moenave Formation were deposited during a period of significant change in the Early Jurassic, as the area that is now Utah and northern Arizona transitioned from fluvial deposits of the Late Triassic Chinle Formation to mixed fluvial and eolian deposits of the highly arid Early Jurassic environment above a major but subtle regional unconformity. We measured a short section of the Moenave Formation outside of Cedar City, Utah, and collected nine representative samples of sandstone and silicified “silcrete” for petrographic analysis. The goal of petrographic analysis was to assess changes in sedimentary texture and composition to provide better context for tectonic and climatic changes affecting this Early Jurassic system. We present our thirty-one meter measured section as well as thin section imagery and point count data collected using the Gazzi-Dickinson method. The initial results, when plotted using the QtFL Provenance Plot, show that grains are of a recycled orogenic origin.This is in agreement with published materials on both the Moenave Formation’s provenance, and is in congruence with the tectonic setting of the Early Jurassic.