Document Type


Date of Degree Completion

Fall 2004

Degree Name

Master of Science (MS)


Geological Sciences

Committee Chair

Lisa L. Ely

Second Committee Member

Jim E. O'Connor

Third Committee Member

Karl Lillquist


A large late-Pleistocene flood traveled into the Owyhee River as a result of a rise and subsequent outburst from pluvial Lake Alvord in southeastern Oregon. Lake Alvord breached Big Sand Gap after reaching an elevation of 1292 m, releasing 11.3 km3 into the adjacent Coyote Basin before stabilizing at an elevation of about 1280 m. Overflow then spilled out of the Coyote Basin through two outlets at 1278 m and into the Crooked Creek drainage of the Owyhee River. The flood created a series of deeply incised canyons, scabland topography and deposited numerous boulder bars containing imbricated clasts up to 4.1 m in diameter. The Alvord and Coyote basins also held older, higher elevation lakes that may have released earlier floods down Crooked Creek. Shoreline features at 1292 m and 1280 m in the Alvord Basin have similar weathering characteristics to the flood deposits observed along Crooked Creek, indicating that most mapped flood features occurred during the late-Pleistocene breach.