Document Type


Date of Degree Completion

Spring 2010

Degree Name

Master of Science (MS)


Geological Sciences

Committee Chair

Lisa Ely

Second Committee Member

Beth Pratt-Sitaula

Third Committee Member

Marie Ferland


Multiple lava dams and correlating lakes impacted the Quaternary evolution of the Owyhee River. Sediment records from lava-dammed lakes were investigated to understand effects of the West Crater (WC) lava dam (~70 ka), the Saddle Butte 2 lava dam (~144 ka), and the Bogus Rim lava dam (~1.9 Ma). Evidence from the WC lava dam and related features indicates that dam duration consisted of five stages (1) dam and lake formation at ~70 ka; (2) dam overflow and lake sedimentation from ~70–46 ka; (3) removal of lava dam and lake termination from ~46 ka to at least 36 ka; (4) incision of underlying units from ~36–15 ka; and (5) incision to modern river level from ~15–0 ka. The WC lava dam lasted ~24,000 yrs and ~31,000 yrs of incision was needed to reestablish the river. This information gives perspective on the effects of lava dams on fluvial landscapes.