Event Title

Paleohydrology of the Pleistocene Bear River and Pluvial Lake Bonneville

Presenter Information

Skye Cooley

Location

Eccles Conference Center

Event Website

http://water.usu.edu/

Start Date

4-3-2009 10:20 AM

End Date

4-3-2009 10:40 AM

Description

The rise of Lake Bonneville to its late Pleistocene highstand (30-15 ka) appears anomalously large. The lake grew ten-fold in area and is the only great Basin pluvial lake to overflow its threshold catastrophically. Lake expansion has traditionally been attributed to a climate shift where southward displacement of the jet stream brought cooler, wetter conditions to the region. Alternatively, the Bear River may have contributed to the lake's expansion following its diversion south by young volcanics. Despite decades of speculation, little effort has been directed towards mapping and dating Bear River deposits in the key region where it enters the basin. Pleistocene deposits and volcanics near Oneida Narrows record the arrival of the river to Lake Bonneville, but the timing remains imprecise. Ambiguities on the order of 50,000 years exist. Previous geochronology work in Bonneville Basin is abundant, but mostly focused on indirect dating by radiocarbon methods or amino-acid zonation. Precisely when the Bear River began emptying into the lake and the hydrological impact on lake levels has not been factored into Great Basin paleoclimate models. An accurate chronology would help workers test hypotheses and provide a common basis for interdisciplinary research into questions concerning the paleoclimatologic, paleobiologic, and paleohydrologic evolution of the Bonneville Basin and beyond.

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Apr 3rd, 10:20 AM Apr 3rd, 10:40 AM

Paleohydrology of the Pleistocene Bear River and Pluvial Lake Bonneville

Eccles Conference Center

The rise of Lake Bonneville to its late Pleistocene highstand (30-15 ka) appears anomalously large. The lake grew ten-fold in area and is the only great Basin pluvial lake to overflow its threshold catastrophically. Lake expansion has traditionally been attributed to a climate shift where southward displacement of the jet stream brought cooler, wetter conditions to the region. Alternatively, the Bear River may have contributed to the lake's expansion following its diversion south by young volcanics. Despite decades of speculation, little effort has been directed towards mapping and dating Bear River deposits in the key region where it enters the basin. Pleistocene deposits and volcanics near Oneida Narrows record the arrival of the river to Lake Bonneville, but the timing remains imprecise. Ambiguities on the order of 50,000 years exist. Previous geochronology work in Bonneville Basin is abundant, but mostly focused on indirect dating by radiocarbon methods or amino-acid zonation. Precisely when the Bear River began emptying into the lake and the hydrological impact on lake levels has not been factored into Great Basin paleoclimate models. An accurate chronology would help workers test hypotheses and provide a common basis for interdisciplinary research into questions concerning the paleoclimatologic, paleobiologic, and paleohydrologic evolution of the Bonneville Basin and beyond.

https://digitalcommons.usu.edu/runoff/2009/AllAbstracts/38