Birth of the lower Colorado River near Laughlin Nevada by Kyle House

Key stratigraphic section that documents the abrupt arrival of the Colorado River in the Laughlin-Bullhead City area approximately 5.59 million years ago. Five strata exposed here document the transition of this basin from a hydrologically closed basin to one containing a very large, sediment laden throughgoing river. The transition involved an initial influx of water associated with an overflowing lake in the basin upstream which culminated in a catastrophic flood through a bedrock divide at the location of Davis Dam. The rapid influx of water and sediment ultimately resulted in a large, deep lake that inundated both Mohave Valley and Cottonwood Valley between 5.59 and 4.1 million years ago. The demise of this large lake preceded the arrival of the throughgoing Colorado River which initially filled the valleys with nearly 300 m of gravel and sand.