## Breadcrumb

-  Publications 
-  Articles 

#           Redefining the age of the lower Colorado River, southwestern United States      

      February 22, 2021    

Sanidine dating and magnetostratigraphy constrain the timing of integration of the lower Colorado River (southwestern United States and northern Mexico) with the evolving Gulf of California. The Colorado River arrived at Cottonwood Valley (Nevada and Arizona) after 5.24 Ma (during or after the Thvera subchron). The river reached the proto–Gulf of California once between 4.80 and 4.63 Ma (during the C3n.2r subchron), not at 5.3 Ma and 5.0 Ma as previously proposed. Duplication of section across newly identified strands of the Earthquake Valley fault zone (California) probably explains the discrepancy. The data also imply the start of focused plate motion and basin development in the Salton Trough (California) at 6–6.5 Ma and relative tectonic stability of the southernmost part of the lower Colorado River corridor after its integration. After integration, the Colorado River quickly incised through sediment-filled basins and divides between them as it also likely excavated Grand Canyon (Arizona). The liberated sediment from throughout the system led to deposition of hundreds of meters of Bullhead Alluvium downstream of Grand Canyon after 4.6 Ma as the river adjusted to its lower base level.

## Citation Information

## Related Content

                  -              Science           
                  -              Connect           

link

April 2, 2021

####                 Geologic Mapping of the Lower Colorado River System              

National Cooperative Geologic Mapping Program, Geology, Minerals, Energy, and Geophysics Science Center

link

April 2, 2021

####   Geologic Mapping of the Lower Colorado River System

Learn More

#### Ryan Crow, Ph.D.

##### Research Geologist

Geology, Minerals, Energy, and Geophysics Science Center

rcrow@usgs.gov

928-556-7148

#### Mark E. Stelten, PhD

##### Geochronologist

California Volcano Observatory

mstelten@usgs.gov

650-329-5213

## Related Content

link

April 2, 2021

####                 Geologic Mapping of the Lower Colorado River System              

National Cooperative Geologic Mapping Program, Geology, Minerals, Energy, and Geophysics Science Center

link

April 2, 2021

####   Geologic Mapping of the Lower Colorado River System

Learn More

#### Ryan Crow, Ph.D.

##### Research Geologist

Geology, Minerals, Energy, and Geophysics Science Center

rcrow@usgs.gov

928-556-7148

#### Mark E. Stelten, PhD

##### Geochronologist

California Volcano Observatory

mstelten@usgs.gov

650-329-5213

### Study Area

### Contact

####               Geology, Minerals, Energy, and Geophysics Science Center          

Building 19, 350 N. Akron Rd.P.O. Box 158Moffett Field, CA94035United States

#### USGS Volcano Science Center

1300 SE Cardinal CourtVancouver, WA38683United States

360-993-8900

### Explore Search

                  - Geology
                  - Maps and Mapping
                  - Mexico
                  -  United States
                  - lower colorado river
                  - Arizona
                  -  California
                  -  Nevada

View All **