Physical Sciences and Mathematics Commons^™

Quaternary Bear River Paleohydrogeography Reconstructed From The 87sr/86sr Composition Of Lacustrine Fossils, David P. Bouchard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Diverted from its former course to the Pacific Ocean by basalt flows in Gem Valley, Idaho, the Bear River presently flows south into the Bonneville Basin. Constraining the timing of the river's diversion is pivotal to understanding the hydrologic budgets, and thus the climatological implications of the Bonneville Basin lakes. This study employs strontium (Sr) isotopes in mollusc fossils as a tracer of the Bear River water that entered Lake Thatcher, a small, closed-basin lake into which the redirected river flowed en route to the Bonneville Basin. The Sr ratios, combined with the temporal control afforded by amino acid geochronology …