Characterization of a Pleistocene lacustrine spit to serve as a depositional model for large scale lacustrine deposits

Abstract

The Green River play in the Uinta Basin is perhaps the fastest developing black oil play of the Rockies today. The carbonate dominated Uteland Butte and Upper Wasatch intervals are well understood as important components to the play, however, the clastic components in the Lower Wasatch, Castle Peak, and Douglas Creek units are less understood. This study uses groundpenetrating- radar (GPR) methods to characterize a shoreline deposit from ancient Lake Bonneville to serve as a depositional model for the Lower Wasatch, Castle Peak, and Douglas Creek units. Lake Bonneville was a Pleistocene pluvial lake which formed in the Great Basin in the western United States. During the transgressive period of the lake, shoreline features such as spits were deposited from alluvium and weathered bedrock documenting key information about lake level and depositional patterns of the spit. GPR offers high-resolution images of the stratigraphy of the spit deposit at a shallow depth. In northwest Utah, a Lake Bonneville spit located adjacent to highway 30, provides an excellent natural laboratory for imaging due to flat terrain, low-clay, low-salinity, and low-moisture content of the site. Moreover, facies associations of the spit help describe and reconstruct the original depositional patterns. Two and three dimensional GPR images show the fine stratigraphic detail of the spit. Using seismic stratigraphy and GPR data will add insights for a model of transgressive deposits in a lacustrine environment and additionally give a comparison to regressive deposits studied with GPR data in the area. This model can present a basis of understanding for similar deposits on a larger scale and help explain the clastic components of the Lower Wasatch, Castle Peak, and Douglas Creek units.

AAPG Datapages/Search and Discovery Article #90357 ©2019 AAPG Rocky Mountain Section Meeting, Cheyenne, Wyoming, September 15-18, 2019