Collaborators: The Colorado River Indian Tribes, Dr. Andy Cohen and Dr. Marty Pepper, Department of Geosciences, CRIT/La Paz County Cooperative Extension 4-H program led by Ms. Debbie Pettigrew, Dr. Jordon Bright, Northern Arizona University, et al.
Recently, both in scientific and public realms, there has been a lot of discussion and debate about the age of the Grand Canyon and the evolution of the Colorado River system. Although deposits related to the Colorado River’s early history have largely been removed from the Grand Canyon they are very well exposed downstream from it in the lower Colorado River corridor, and are spectacularly exposed on CRIT tribal lands in the Mesquite Mountain area near Parker, AZ. Two main units are present: 1) the Bouse Formation which records the first arrival of Colorado River water and sediment at about 5 million years ago, and 2) the Bullhead Alluvium, which records the first arrival of coarse sediment and gravel, possibly related to the carving of Grand Canyon, around 4 million years ago. USGS geologists first studied these deposits in detail in the 1970s, as the sands and gravels of the Bouse and Bullhead rock units typically hold much of the shallow groundwater resources in the area. Although that and subsequent research has greatly improved our understanding of these units and how they formed, continued work is needed to better understand the timing and exact processes by which the Colorado River was able to reach the Gulf of California.
The project, based in Parker, Arizona, on the CRIT reservation, is a grant-funded, multi-university geoscientific investigation, approved by the CRIT Tribal Council in the fall of 2019. The project involves both scientific studies conducted by a team of university, federal and state agency scientists, and the CRIT 4-H student STEM outreach initiative. Four Parker High School students are members of the team, supervised by Debbie Pettigrew, CRIT Program Coordinator, Sr. 4-H Youth Development. The student initiative engages the students in all field research activities, and all have received training in basic geosciences, data collection, videography (a film of their experiences is under production), and drone aeronautics. UArizona Professor Marty Pepper is directing all student field activities and is chief videographer for the project.
The direct, ground-based research is divided into two phases: (1) rock sampling and geoscientific measurements in the Bouse formation which occurred in February 2020; and (2) seismic survey data collection, which was completed in November 2021. Research continues on both the rock sampling and seismic data. A final report will be provided to the Colorado River Indian Tribes when the research is completed.