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Prospect Dam is a former lava dam in the Grand Canyon of Arizona, United States. It was the oldest and tallest of several former lava dams in the Grand Canyon. [1] It was formed about 1.2 million years ago as lava flowed down the walls of the Grand Canyon, and temporarily stopped the flow of the Colorado River. [2]
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 geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America. Both marine and terrestrial sediments are represented, including lithified sand dunes from an extinct desert. There are at least 14 known unconformities in the geologic record found in the Grand Canyon.
Lees Ferry is a site on the Colorado River in Coconino County, Arizona in the United States, about 7.5 miles (12.1 km) southwest of Page and 9 miles (14 km) south of the Utah–Arizona state line.
Havasu Falls is a waterfall of Havasu Creek, located in the Grand Canyon, Arizona, United States. It is within Havasupai tribal lands.
The Mount Trumbull Wilderness is a 7,880 acre (31 km2) wilderness area located on the Uinkaret Plateau in the Arizona Strip. It is managed by the Bureau of Land Management.
S P Crater is a cinder cone volcano in the San Francisco volcanic field, 25 miles (40 km) north of Flagstaff, Arizona, United States. It is surrounded by several other cinder cones which are older and more eroded. It is a striking feature on the local landscape, with a well-defined lava flow that extends for 4.3 miles (7 km) to the north. American astronauts use the crater to train for moonwalking.
The Uinkaret volcanic field is an area of monogenetic volcanoes in northwestern Arizona, United States, located on the north rim of the Grand Canyon.
Vulcan's Throne is a cinder cone volcano and a prominent landmark on the North Rim of the Grand Canyon in Arizona, United States. The volcano is adjacent the Colorado River, as it is the source material for Lava Falls and Lava Falls Rapids one of the largest rapids of the Colorado. Vulcan's Throne, about a mile (1.7 km) west of Toroweap overlook, is part of the Uinkaret volcanic field. The journals of traveler George Corning Fraser record a trip to the summit of Vulcan's Throne in 1914. At the time, the surrounding area was used for sheep grazing, and a small reservoir had been constructed at the base of the volcano. Fraser wrote that
Vulcan's Throne is a pure cinder cone covered with scoriae, cinders, clinkers and peperino lying loose on the surface, with a slope, as near as I could measure, from 28° to 31°. A little sage, many cacti and perhaps some other similar low plants grow on it, but otherwise nothing. Climbing it was like ascending a sand-dune. Every step forward involved slipping half way back and boots were soon filled with painful bits of stone.
The Lava Falls Trail is a hiking trail on the North Rim of the Grand Canyon National Park, located in the U.S. state of Arizona. It descends from the north rim of the Grand Canyon just west of the extinct volcano known as Vulcan's Throne to the Colorado River.
The Tuckup Trail is a 100-mile-long (160 km) hiking trail on the North Rim of the Grand Canyon, in Grand Canyon National Park, located in the U.S. state of Arizona.
Pearce Ferry marks the boundary between Lake Mead and the Grand Canyon, where the low sandy banks around the lake give way to imposing, colorfully layered cliffs that enclose the Colorado River for the next 277 miles upstream. Lake Mead, and all of its points of interest, is managed by the National Park Service and available to the public for recreational purposes. A ferry was operated here by the Pearce family starting around 1876.
Bridge Canyon Dam, also called Hualapai Dam, was a proposed dam in the lower Grand Canyon of the Colorado River, in northern Arizona in the United States. It would have been located near Bridge Canyon Rapids in an extremely rugged and isolated portion of the canyon, 235 miles (378 km) downstream of Lees Ferry and at the uppermost end of Lake Mead.
The Colorado River is a major river of the western United States and northwest Mexico in North America. Its headwaters are in the Rocky Mountains where La Poudre Pass Lake is its source. Located in north central Colorado it flows southwest through the Colorado Plateau country of western Colorado, southeastern Utah and northwestern Arizona where it flows through the Grand Canyon. It turns south near Las Vegas, Nevada, forming the Arizona–Nevada border in Lake Mead and the Arizona–California border a few miles below Davis Dam between Laughlin, Nevada and Needles, California before entering Mexico in the Colorado Desert. Most of its waters are diverted into the Imperial Valley of Southern California. In Mexico its course forms the boundary between Sonora and Baja California before entering the Gulf of California. This article describes most of the major features along the river.
The Cardenas Basalt, also known as either the Cardenas Lava or Cardenas Lavas, is a rock formation that outcrops over an area of about 310 km2 (120 mi2) in the eastern Grand Canyon, Coconino County, Arizona. The lower part of the Cardenas Basalt forms granular talus slopes. Its upper part forms nearly continuous low cliffs that are parallel to the general course of the Colorado River. The most complete, readily accessible, and easily studied exposure of the Cardenas Basalt lies in Basalt Canyon. This is also its type locality.
The Unkar Group is a sequence of strata of Proterozoic age that are subdivided into five geologic formations and exposed within the Grand Canyon, Arizona, Southwestern United States. The 5-unit Unkar Group is the basal member of the 8-member Grand Canyon Supergroup. The Unkar is about 1,600 to 2,200 m thick and composed, in ascending order, of the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt. Units 4 & 5 are found mostly in the eastern region of Grand Canyon. Units 1 through 3 are found in central Grand Canyon. The Unkar Group accumulated approximately between 1250 and 1104 Ma. In ascending order, the Unkar Group is overlain by the Nankoweap Formation, about 113 to 150 m thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the Sixtymile Formation, about 60 m (200 ft) thick. These are all of the units of the Grand Canyon Supergroup. The Unkar Group makes up approximately half of the thickness of the 8-unit Supergroup.
The Bass Formation, also known as the Bass Limestone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The Bass Formation erodes as either cliffs or stair-stepped cliffs. In the case of the stair-stepped topography, resistant dolomite layers form risers and argillite layers form steep treads. In general, the Bass Formation in the Grand Canyon region and associated strata of the Unkar Group-rocks dip northeast (10°–30°) toward normal faults that dip 60+° toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area. In addition, thick, prominent, and dark-colored basaltic sills intrude across the Bass Formation.
The Dox Formation, also known as the Dox Sandstone, is a Mesoproterozoic rock formation that outcrops in the eastern Grand Canyon, Coconino County, Arizona. The strata of the Dox Formation, except for some more resistant sandstone beds, are relatively susceptible to erosion and weathering. The lower member of the Dox Formation consists of silty-sandstone and sandstone, and some interbedded argillaceous beds, that form stair-stepped, cliff-slope topography. The bulk of the Dox Formation typically forms rounded and sloping hill topography that occupies an unusually broad section of the canyon.
Toroweap Overlook is a viewpoint within the Grand Canyon National Park in Arizona, United States. It is located in a remote area on the North Rim of the Grand Canyon, 55 miles (89 km) west of the North Rim Headquarters. The overlook is the only viewpoint in the National Park from where the Colorado River can be seen vertically below. The overlook stands 3,000 feet (910 m) above the river.
Hyaloclastite Dam was a 1,201 ft (366 m) high lava dam that occupied the Grand Canyon of the U.S. state of Arizona. It formed during the Pleistocene epoch when basaltic lava flows from the Uinkaret volcanic field blocked the Colorado River. The dam failed catastrophically 160,000 years ago to produce the largest known outburst flood on the Colorado River in the Grand Canyon. A slump block of basalt is the remaining remnant of the Hyaloclastite Dam.