| Description |
Lake Bonneville was the largest of the Pleistocene pluvial lakes that once filled part of the Great Basin of the interior western United States. As the lake reached its highest level at the Bonneville shoreline and overflowed, it eroded through alluvium at Red Rock Pass, Idaho, and quickly dropped over 100 m to the Provo shoreline. This unique flooding history and resulting rapid lake-level fall allows us to assume that all other shorelines with elevations between the Bonneville and Provo levels formed during the lake's transgressive phase. Various types of depositional features characterize the shorelines within this transgressive interval, including many forms of barriers. This study uses 5-m auto-correlated digital elevation models (DEMs), airborne light detection and ranging (lidar), and ground-penetrating radar (GPR) surveys to measure the internal and external structure of intermediate barriers in late Pleistocene Lake Bonneville. Corrections for differential isostatic rebound reveal only one confidently correlatable intermediate shoreline at 1530 m (+/- 4 m) while differences in barrier morphology indicate that the formation of depositional features is highly dependent on local, not basin-scale, conditions. |
