Changes in Rate of Transgression Across the Permian White Rim Sandstone, Southern Utah

Abstract

ABSTRACT A change in the rate of transgression of the Permian Kaibab sea across southern Utah is proposed on the basis of stratal relations and preserved paleotopography in the Permian White Rim Sandstone. As the Kaibab sea transgressed southern Utah, across a generally west-dipping continental margin, the rate of transgression increased. Interbedded coastal dune sandstones (White Rim Sandstone) and marine carbonates (Kaibab limestone) reflect slow transgression across what is now south-central Utah. Preserved paleotopography and the absence of intertonguing of carbonates and sandstones in southeastern Utah reflects a more rapid transgression, indicating that the rate of sea-level rise increased with time. Throughout the transgression, relative rise in sea level was discontinuous, and punctuat d by stillstands. In general, intervening stillstands decreased in duration as the transgression progressed. This change in transgression rate can be interpreted in one of two ways: rate of regional sea-level rise across southern Utah increased with time, or previously unrecognized and localized subsidence occurred in eastern Utah during Kaibab transgression. Although regional tectonism is important, we favor the former interpretation because no independent evidence of local tectonic movement can be found.