Question: When did the body of water containing Shadow Mountain Dam start to form the grand canyon?

full_context: Document 1: Outflow channels: Outflow channels are extremely long, wide swathes of scoured ground on Mars, commonly containing the streamlined remnants of pre-existing topography and other linear erosive features indicating sculpting by fluids moving downslope. Channels extend many hundreds of kilometers in length and are typically greater than one kilometer in width; the largest valley (Kasei Vallis) is around long, greater than wide and exceeds in depth cut into the surrounding plains. These features tend to appear fully sized at fractures in the Martian surface, either from chaos terrains or from canyon systems or other tectonically controlled, deep graben, though there are exceptions. Besides their exceptional size, the channels are also characterized by low sinuosities and high width:depth ratios compared both to other Martian valley features and to terrestrial river channels. Crater counts indicate that most of the channels were cut since the early Hesperian, though the age of the features is variable between different regions of Mars. Some outflow channels in the Amazonis and Elysium Planitiae regions have yielded ages of only tens of million years, extremely young by the standards of Martian topographic features.
Document 2: Mars: The large canyon, Valles Marineris (Latin for ``Mariner Valleys '', also known as Agathadaemon in the old canal maps), has a length of 4,000 km (2,500 mi) and a depth of up to 7 km (4.3 mi). The length of Valles Marineris is equivalent to the length of Europe and extends across one - fifth the circumference of Mars. By comparison, the Grand Canyon on Earth is only 446 km (277 mi) long and nearly 2 km (1.2 mi) deep. Valles Marineris was formed due to the swelling of the Tharsis area, which caused the crust in the area of Valles Marineris to collapse. In 2012, it was proposed that Valles Marineris is not just a graben, but a plate boundary where 150 km (93 mi) of transverse motion has occurred, making Mars a planet with possibly a two - tectonic plate arrangement.
Document 3: Geology: All of these processes do not necessarily occur in a single environment, and do not necessarily occur in a single order. The Hawaiian Islands, for example, consist almost entirely of layered basaltic lava flows. The sedimentary sequences of the mid-continental United States and the Grand Canyon in the southwestern United States contain almost-undeformed stacks of sedimentary rocks that have remained in place since Cambrian time. Other areas are much more geologically complex. In the southwestern United States, sedimentary, volcanic, and intrusive rocks have been metamorphosed, faulted, foliated, and folded. Even older rocks, such as the Acasta gneiss of the Slave craton in northwestern Canada, the oldest known rock in the world have been metamorphosed to the point where their origin is undiscernable without laboratory analysis. In addition, these processes can occur in stages. In many places, the Grand Canyon in the southwestern United States being a very visible example, the lower rock units were metamorphosed and deformed, and then deformation ended and the upper, undeformed units were deposited. Although any amount of rock emplacement and rock deformation can occur, and they can occur any number of times, these concepts provide a guide to understanding the geological history of an area.
Document 4: Grand Canyon: Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago. Since that time, the Colorado River has driven the down - cutting of the tributaries and retreat of the cliffs, simultaneously deepening and widening the canyon.
Document 5: Grand Canyon: The Grand Canyon (Hopi: Ongtupqa; Yavapai: Wi: kaʼi: la, Navajo: Tsékooh Hatsoh, Spanish: Gran Cañón) is a steep - sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters).
Document 6: Grand Lake (Colorado): Grand Lake is Colorado's largest and deepest natural lake. It is located in the headwaters of the Colorado River in Grand County, Colorado. On its north shore is located the historic and eponymous town of Grand Lake. The lake fills a glaciated valley that is dammed in part by glacial till from the Pinedale Glaciation, and is younger than about 12,000 years. Natural tributaries to the lake are the North Inlet and East Inlet, both of which flow out of Rocky Mountain National Park, which surrounds the lake on three sides: Grand Lake is located 1 mile from the Park's western entrance. Grand Lake was named Spirit Lake by the Ute Tribe because they believed the lake's cold waters to be the dwelling place of departed souls.
Document 7: Grand Valley Diversion Dam: The Grand Valley Diversion Dam is a diversion dam in the De Beque Canyon of the Colorado River, about northeast of Grand Junction, Colorado in the United States. It is a high, long concrete roller dam with six gates, which were the first and largest of their kind to be installed in the United States.
Document 8: Grand Canyon: The Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and is also one of the six distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world (Kali Gandaki Gorge in Nepal is much deeper). However, the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent.
Document 9: Deer Creek Dam and Reservoir: The Deer Creek Dam and Reservoir hydroelectric facilities are on the Provo River in western Wasatch County, Utah, United States, about northeast of Provo. The dam is a zoned earthfill structure high with a crest length of . The dam contains 2,810,000 cubic yards (2,150,000 m³) of material and forms a reservoir of capacity. Construction began in May 1938 and was completed in 1941. The reservoir supplies water for agricultural, municipal and industrial use. Recreational activities on and around the reservoir include boating, fishing, camping, swimming and water skiing.
Document 10: Keyhole State Park: The Keyhole Reservoir, an impoundment of the Belle Fourche River, was formed by the Keyhole Dam project of the United States Bureau of Reclamation, completed in 1952. The reservoir has a total capacity of 334,200 acre-feet and water surface of 13,700 acres, which provides storage for irrigation, flood control, fish and wildlife conservation, recreation, sediment control, and municipal and industrial water supply. Although located in Wyoming, the reservoir's waters are allocated by compact to go 90 percent to South Dakota and 10 percent to Wyoming.
Document 11: Geological history of Earth: The geological history of Earth follows the major events in Earth's past based on the geologic time scale, a system of chronological measurement based on the study of the planet's rock layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk - shaped mass of dust and gas left over from the formation of the Sun, which also created the rest of the Solar System.
Document 12: Candor Chasma: Candor Chasma is one of the largest canyons in the Valles Marineris canyon system on Mars. The feature is geographically divided into two halves: East and West Candor Chasmas, respectively. It is unclear how the canyon originally formed; one theory is that it was expanded and deepened by tectonic processes similar to a graben, while another suggests that it was formed by subsurface water erosion similar to a karst. MRO discovered sulfates, hydrated sulfates, and iron oxides in Candor Chasma.
Document 13: Shadow Mountain Dam: Shadow Mountain Dam is a zoned earth-fill dam on the Colorado River in Grand County, Colorado. Constructed between 1944 and 1946, the Shadow Mountain Dam creates the Shadow Mountain Lake, with a structural height of and a drainage area of . Shadow Mountain Lake is a holding reservoir for water pumped up from Lake Granby just to the south through the Granby Pumping Plant and Canal. Shadow Mountain Lake is connected by a short channel to the natural Grand Lake. The west portal of the Alva B. Adams Tunnel is located on Grand Lake. The Adams Tunnel diverts west slope water to the east slope of the Rocky Mountains for use in agriculture and to serve the populated areas of Colorado, including Denver.
Document 14: Tunnel Reservoir: Tunnel Reservoir is an artificial lake and recreational area located in the White Mountains around the town of Greer, Arizona. This reservoir is one of three lakes known as the Greer Lakes. The Greer Lakes include Bunch, Tunnel and River Reservoirs, and are a short distance apart from each other. The boating facility offers a boat launching area, boat trailer parking, restrooms, and space for recreational vehicles. The reservoir is stocked with Rainbow and Brown trout species.
Document 15: Kingsley Dam: Kingsley Dam is located on the east side of Lake McConaughy in central Keith County, Nebraska, and is the second largest hydraulic fill dam in the world. It was built as part of the New Deal project. The dam is tall, long, and wide at its base. On the east side of the dam is Lake Ogallala and on the south side is the Kingsley Hydroelectricity Plant. The Nebraska Game and Parks Commission and Central Nebraska Public Power and Irrigation District are also located in this area. Kingsley Dam, the Kingsley Hydroelectricity Plant, the Morning Glory Spillway, and the Outlet Tower – a large structure near the dam used to release water from the lake – are main visual icons of Lake McConaughy.
ground_truth: about 5 to 6 million years ago
sub_queries: Shadow Mountain Dam >> located on terrain feature Answer: Colorado River
when did Colorado River start to form the grand canyon Answer: about 5 to 6 million years ago