Question: When did the the river where Southern California gets most of its water, start to form the Grand Canyon?

full_context: Document 1: 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 2: 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 3: 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 4: Water in California: Rivers of the Lahontan watersheds in eastern California are part of the high desert Great Basin and do not drain to the Pacific. Most of the water is used locally in eastern California and western Nevada for irrigation. The Owens River of the South Lahontan region, however, is a principal source of water for Los Angeles.
Document 5: Southern California: To the east is the Colorado Desert and the Colorado River at the border with Arizona, and the Mojave Desert at the border with the state of Nevada. To the south is the Mexico–United States border.
Document 6: Red Desert (Wyoming): The Red Desert is a high altitude desert and sagebrush steppe located in south central Wyoming, comprising approximately 9,320 square miles (24,000 km). Among the natural features in the Red Desert region are the Great Divide Basin, a unique endorheic drainage basin formed by a division in the Continental Divide, and the Killpecker Sand Dunes, the largest living dune system in the United States. In the 19th century, the Oregon, California and Mormon Trails crossed the Continental Divide at South Pass, just north of the Red Desert. Today, busy Interstate 80 bisects the desert's southern region while gas field roads cross the desert.
Document 7: Water in California: The Colorado River originates more than 1,000 miles (1,600 km) from California in the Rocky Mountains of Colorado and Wyoming and forms the state's southeastern border in the Mojave Desert. Unlike the other California watersheds, essentially all of the water flowing in the Colorado originates outside the state. The Colorado is a critical source of irrigation and urban water for southern California, providing between 55 and 65 percent of the total supply.
Document 8: 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 9: Colorado River: Colorado River The Colorado River at Horseshoe Bend, Arizona, a few miles below Glen Canyon Dam Countries United States, Mexico States Colorado, Utah, Arizona, Nevada, California, Baja California, Sonora Tributaries - left Fraser River, Blue River, Eagle River, Roaring Fork River, Gunnison River, Dolores River, San Juan River, Little Colorado River, Bill Williams River, Gila River - right Green River, Dirty Devil River, Escalante River, Kanab River, Virgin River, Hardy River Cities Glenwood Springs, CO, Grand Junction, CO, Moab, UT, Page, AZ, Bullhead City, AZ, Lake Havasu City, AZ, Yuma, AZ, San Luis Rio Colorado, SON Source La Poudre Pass - location Rocky Mountains, Colorado, United States - elevation 10,184 ft (3,104 m) - coordinates 40 ° 28 ′ 20 ''N 105 ° 49 ′ 34'' W ﻿ / ﻿ 40.47222 ° N 105.82611 ° W ﻿ / 40.47222; - 105.82611 Mouth Gulf of California - location Colorado River Delta, Baja California -- Sonora, Mexico - elevation 0 ft (0 m) - coordinates 31 ° 54 ′ 00 ''N 114 ° 57 ′ 03'' W ﻿ / ﻿ 31.90000 ° N 114.95083 ° W ﻿ / 31.90000; - 114.95083 Coordinates: 31 ° 54 ′ 00 ''N 114 ° 57 ′ 03'' W ﻿ / ﻿ 31.90000 ° N 114.95083 ° W ﻿ / 31.90000; - 114.95083 Length 1,450 mi (2,334 km) Basin 246,000 sq mi (637,137 km) Discharge for mouth (average virgin flow), max and min at Topock, AZ, 300 mi (480 km) from the mouth - average 22,500 cu ft / s (637 m / s) - max 384,000 cu ft / s (10,900 m / s) - min 422 cu ft / s (12 m / s) Map of the Colorado River basin Wikimedia Commons: Colorado River
Document 10: Colorado River Compact: The Colorado River Compact is a 1922 agreement among seven U.S. states in the basin of the Colorado River in the American Southwest governing the allocation of the water rights to the river's water among the parties of the interstate compact. The agreement was signed at a meeting at Bishop's Lodge, near Santa Fe, New Mexico, by representatives of the seven states the Colorado river and its tributaries pass through on the way to Mexico.
Document 11: 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 12: 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 13: Colorado River (Texas): Colorado River Texas The Colorado River in Austin, as seen from Mount Bonnell. Country United States State Texas Source - location Dawson County - elevation 3,280 ft (1,000 m) - coordinates 32 ° 40 ′ 47 ''N 101 ° 43 ′ 51'' W ﻿ / ﻿ 32.67972 ° N 101.73083 ° W ﻿ / 32.67972; - 101.73083 Mouth Matagorda Bay - location Gulf of Mexico, at Matagorda County, Texas - elevation 0 ft (0 m) - coordinates 28 ° 35 ′ 41 ''N 95 ° 58 ′ 59'' W ﻿ / ﻿ 28.59472 ° N 95.98306 ° W ﻿ / 28.59472; - 95.98306 Coordinates: 28 ° 35 ′ 41 ''N 95 ° 58 ′ 59'' W ﻿ / ﻿ 28.59472 ° N 95.98306 ° W ﻿ / 28.59472; - 95.98306 Length 862 mi (1,387 km) Basin 39,900 sq mi (103,341 km) Discharge for Bay City - average 2,609 cu ft / s (74 m / s) - max 84,100 cu ft / s (2,381 m / s) - min 0 cu ft / s (0 m / s) Map of the Colorado River and associated watershed
Document 14: 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 15: 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.
ground_truth: about 5 to 6 million years ago
sub_queries: where does southern california get most of its water Answer: The Colorado River
when did The Colorado River start to form the grand canyon Answer: about 5 to 6 million years ago