Grand Canyon

The Grand Canyon is a steep-sided gorge in northern Arizona, carved chiefly by the Colorado River. Its exposed rock layers record a long history of geological processes.

Colorado River: The major river of the southwestern United States that flows through the Grand Canyon. Its flow has cut the canyon and continues to transport sediment through it.
Stratigraphy: The study of layered rocks and their relationships through time. The canyon’s exposed strata reveal changing environments across geological periods.
Grand Canyon age debate: Scientific debate over when the Grand Canyon’s present depth and integrated river course formed. Different dating methods support competing timelines for canyon incision.
Havasu Creek: A tributary of the Colorado River known for turquoise water and waterfalls in the Grand Canyon. Its travertine dams and falls show how mineral-rich groundwater builds distinctive canyon features.
Colorado River Compact: A 1922 agreement dividing the Colorado River’s water among participating states. Upstream water allocation affects river flow, sediment transport, and ecosystems downstream.
Colorado Plateau: A high, arid region of the southwestern United States underlain by largely flat-lying sedimentary rocks. Uplift raised the plateau while the Colorado River incised the canyon.
Unconformity: A surface in the rock record representing a gap in deposition or a period of erosion. The Great Unconformity separates ancient crystalline rocks from younger sedimentary layers.
Colorado River drainage: The network of rivers and tributaries that carries water across the Colorado Plateau toward the Gulf of California. The integration of this drainage system established the river route through the canyon.
Little Colorado River: A major tributary that joins the Colorado River near the eastern end of the Grand Canyon. Its confluence marks a striking geological and cultural landmark.
Glen Canyon Dam: A dam on the Colorado River in northern Arizona that created Lake Powell. Its regulated releases altered the river’s flood regime and sediment movement below the dam.

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