The Uinkaret volcanic field is an area of monogenetic volcanoes in northwestern Arizona, United States, located on the north rim of the Grand Canyon.
Uinkaret volcanic field
Basalts from the Uinkaret volcanic field flow into the Grand Canyon from its North Rim. On the right is Lava Falls, with Vulcan's Throne at the top, just above the brightly lit cliff face at top center. Vulcan's Throne is about 73,000 years old. These are among the most recent features of the Grand Canyon. The topmost layers over which the lava flowed, the Kaibab Limestone, was deposited in Early Permian time, around 290 million years ago.
Vulcan's Throne (top right) and Lava Falls, 2008 aerial photo
The Colorado River is one of the principal rivers in the Southwestern United States and in northern Mexico. The 1,450-mile-long (2,330 km) river, the 5th longest in the United States, drains an expansive, arid watershed that encompasses parts of seven U.S. states and two Mexican states. The name Colorado derives from the Spanish language for "colored reddish" due to its heavy silt load. Starting in the central Rocky Mountains of Colorado, it flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora.
The Colorado River at Horseshoe Bend, Arizona, a few miles below Glen Canyon Dam
Headwaters of the Colorado River in Rocky Mountain National Park, Colorado
Colorado River in the Grand Canyon seen from Pima Point, near Hermit's Rest
Colorado River as it exits the United States into Mexico beneath the San Luis Colorado-Colonia Miguel Aléman Bridge (September 2009)
