This is a comprehensive scientific investigation of the geologic history and framework of the lower Colorado River. We are using geologic mapping in combination with stratigraphic, geochronologic, and geophysical studies to develop a holistic understanding of the river’s origin, the structural history of the landscape through which it flows, and the stratigraphic and geomorphic consequences of the river’s changes in response to long and short-term changes in regional tectonics and climate.
Science Issue and Relevance:
The lower Colorado River study area includes one of the world’s most iconic landscapes (Grand Canyon) and embodies a water resource that is essential to the water and electric power requirements of more than 40 Million people in the southwestern United States.
- There is wide-reaching cultural relevance in simply explaining the Grand Canyon, and we can’t begin to do that without understanding how the lower river corridor evolved.
- Regional crustal extension and associated sedimentary deposits created the characteristics of modern-day aquifers
- Detailed geologic mapping investigations build knowledge and provide deep insights into geologic processes and related natural hazards endemic to the lower Colorado River.
- Maps of the lower Colorado River will be integrated into National geologic map datasets.
Methodology to Address Issue:
Geologic mapping is the foundational method employed in this project. Mapping is a means of documenting, synthesizing and portraying scientific observations and interpretations of geologic deposits that record important episodes and timing of geologic activity. Our project is based primarily on surficial geologic mapping and regional-scale geologic maps but, will also conduct bedrock mapping and related structural studies. Our workflow involves characterizing and portraying a complex stratigraphic record at intermediate scale (e.g., 1:100,000). This process includes new geologic mapping in addition to compilation and refinement of existing maps, using a common stratigraphic nomenclature. These efforts are rely on modern GIS technology.
Geochronologic studies will focus on the ages of key Colorado River strata and underlying bedrock units and geologic structures that have influenced the river’s evolution. Structural and stratigraphic analysis of the geologic framework of the basins that hold voluminous water resources will be critically important in coming years and decades.
Below are other science projects associated with this project.
Aeromagnetic Data and horizontal gradient maxima of Blythe, California, and Surrounding Areas in California and Arizona
Below are publications associated with this project.
Tectonostratigraphic record of late Miocene–early Pliocene transtensional faulting in the Eastern California shear zone, southwestern USA
Oases: Finding hidden biodiversity gems in the southern Sonoran Desert
Post-12 Ma deformation of the lower Colorado River corridor, southwestern USA: Implications for diffuse transtension and the Bouse Formation
The Bouse Formation: A controversial Neogene archive of the evolving Colorado River: A scientific drilling workshop report (Feb. 28-March 3, 2019-Bluewater Resort, Parker, Arizona, USA
Insights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
A river is born: Highlights of the geologic evolution of the Colorado River extensional corridor and its river: A field guide honoring the life and legacy of Warren Hamilton
The Colorado River and its deposits downstream from Grand Canyon in Arizona, California, and Nevada
Below are partners associated with this project.
- Overview
This is a comprehensive scientific investigation of the geologic history and framework of the lower Colorado River. We are using geologic mapping in combination with stratigraphic, geochronologic, and geophysical studies to develop a holistic understanding of the river’s origin, the structural history of the landscape through which it flows, and the stratigraphic and geomorphic consequences of the river’s changes in response to long and short-term changes in regional tectonics and climate.
Deformed sediment of the Bouse Formation in Chemehuevi Valley, California. Complex deformation is a likely consequence of subaqueous mass wasting of part of a growing delta of the Colorado River. Science Issue and Relevance:
The lower Colorado River study area includes one of the world’s most iconic landscapes (Grand Canyon) and embodies a water resource that is essential to the water and electric power requirements of more than 40 Million people in the southwestern United States.
- There is wide-reaching cultural relevance in simply explaining the Grand Canyon, and we can’t begin to do that without understanding how the lower river corridor evolved.
- Regional crustal extension and associated sedimentary deposits created the characteristics of modern-day aquifers
- Detailed geologic mapping investigations build knowledge and provide deep insights into geologic processes and related natural hazards endemic to the lower Colorado River.
- Maps of the lower Colorado River will be integrated into National geologic map datasets.
Methodology to Address Issue:
Geologic mapping is the foundational method employed in this project. Mapping is a means of documenting, synthesizing and portraying scientific observations and interpretations of geologic deposits that record important episodes and timing of geologic activity. Our project is based primarily on surficial geologic mapping and regional-scale geologic maps but, will also conduct bedrock mapping and related structural studies. Our workflow involves characterizing and portraying a complex stratigraphic record at intermediate scale (e.g., 1:100,000). This process includes new geologic mapping in addition to compilation and refinement of existing maps, using a common stratigraphic nomenclature. These efforts are rely on modern GIS technology.
Linear tracts and small patches of well rounded and varnished pebbles and cobbles mark the traces of ancient channels, bars, and floodplain terraces of the lower Colorado River. Extremely long durations of exposure to the desert environment transform the surfaces of these deposits to flat, and tightly packed pavements of spectacularly discolored and varnished river rocks. Geochronologic studies will focus on the ages of key Colorado River strata and underlying bedrock units and geologic structures that have influenced the river’s evolution. Structural and stratigraphic analysis of the geologic framework of the basins that hold voluminous water resources will be critically important in coming years and decades.
Summer flash-floods can introduce large amounts, of fine reddish-orange sediment to the Colorado River with spectacular results - Science
Below are other science projects associated with this project.
- Data
Aeromagnetic Data and horizontal gradient maxima of Blythe, California, and Surrounding Areas in California and Arizona
This data release provides access to an aeromagnetic survey and magnetization boundaries over Blythe, California and surrounding areas in southern California and western Arizona. The survey extends east of Joshua Tree National Park across the Colorado River and west over the Dome Rock, Trigo, and Plomosa Mountains in Arizona. The survey was flown north of the Chocolate Mountains Gunnery Range over - Publications
Below are publications associated with this project.
Tectonostratigraphic record of late Miocene–early Pliocene transtensional faulting in the Eastern California shear zone, southwestern USA
The Eastern California shear zone (ECSZ; southwestern USA) accommodates ~20%–25% of Pacific–North America relative plate motion east of the San Andreas fault, yet little is known about its early tectonic evolution. This paper presents a detailed stratigraphic and structural analysis of the uppermost Miocene to lower Pliocene Bouse Formation in the southern Blythe Basin, lower Colorado River valleyOases: Finding hidden biodiversity gems in the southern Sonoran Desert
In the arid southern Sonoran Desert, the rugged canyons of the Sierra El Aguaje contain numerous freshwater oases. These habitats are supported by small springs which are usually located along geologic faults in volcanic and granitic bedrock. Genetic evidence from freshwater-obligate species (e.g., fish and frogs) suggests these or similar spring-fed habitats have persisted for thousands to millioPost-12 Ma deformation of the lower Colorado River corridor, southwestern USA: Implications for diffuse transtension and the Bouse Formation
Structural evidence presented here documents that deformation was ongoing within the lower Colorado River corridor (southwestern USA) during and after the latest Miocene Epoch, postdating large-magnitude extension and metamorphic core complex formation. Geometric and kinematic data collected on faults in key geologic units constrain the timing of deformation in relation to the age of the Bouse ForThe Bouse Formation: A controversial Neogene archive of the evolving Colorado River: A scientific drilling workshop report (Feb. 28-March 3, 2019-Bluewater Resort, Parker, Arizona, USA
Neogene deposits of the lower Colorado River valley, especially the Miocene(?) and early Pliocene Bouse Formation, have been the focus of intense debate regarding the early paleoenvironmental history of this important continental-scale river system in southwestern North America and its integration with the proto-Gulf of California. Fine-grained units within these Neogene deposits also hold a promiInsights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
The spatial and temporal distribution of Pliocene to Holocene Colorado River deposits (southwestern USA and northwestern Mexico) form a primary data set that records the evolution of a continental-scale river system and helps to delineate and quantify the magnitude of regional deformation. We focus in particular on the age and distribution of ancestral Colorado River deposits from field observatioA river is born: Highlights of the geologic evolution of the Colorado River extensional corridor and its river: A field guide honoring the life and legacy of Warren Hamilton
The Colorado River extensional corridor, which stretched by a factor of 2 in the Miocene, left a series of lowland basins and intervening bedrock ranges that, at the dawn of the Pliocene, were flooded by Colorado River water newly diverted from the Colorado Plateau through Grand Canyon. This water and subsequent sediment gave birth, through a series of overflowing lakes, to an integrated ColoradoThe Colorado River and its deposits downstream from Grand Canyon in Arizona, California, and Nevada
Understanding the evolution of the Colorado River system has direct implications for (1) the processes and timing of continental-scale river system integration, (2) the formation of iconic landscapes like those in and around Grand Canyon, and (3) the availability of groundwater resources. Spatial patterns in the position and type of Colorado River deposits, only discernible through geologic mappin - Partners
Below are partners associated with this project.