When did the source of almost all of the Imperial Valley's water, start to form the Grand Canyon?
about 5 to 6 million years ago
Title: Mars
Passage: 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.
Title: Imperial Valley
Passage: The Imperial Valley extends southward for 50 miles (80 km) from the southern end of the Salton Sea into Mexico. Part of a trough stretching from the Coachella Valley to the Gulf of California, it is almost entirely below sea level -- 235 feet (72 m) below at the edge of the Salton Sea. Its hot desert climate is characterized by daily temperature extremes. It was once part of the Gulf of California, from which it was cut off by the dam - like deposits of the Colorado River Delta Fan as it carved out the Grand Canyon. Bordered by sand dunes and barren mountains, it was uninhabited until 1901, when the Imperial Canal was opened and diverted Colorado River water into the valley through Mexico. Flood - waters in 1905 -- 07 destroyed the irrigation channels and created the Salton Sea now filled by the New River and irrigation run - off. The rivers in the southern part of the Salton Sea river basin flow south to north.
Title: Chihuahua (state)
Passage: The main mountain range in the state is the Sierra Madre Occidental reaching a maximum altitude of 10,826 ft (3,300 m) known as Cerro Mohinora. Mountains account for one third of the state's surface area which include large coniferous forests. The climate in the mountainous regions varies Chihuahua has more forests than any other state in Mexico making the area a bountiful source of wood; the mountainous areas are rich in minerals important to Mexico's mining industry. Precipitation and temperature in the mountainous areas depends on the elevation. Between the months of November and March snow storms are possible in the lower elevations and are frequent in the higher elevations. There are several watersheds located in the Sierra Madre Occidental all of the water that flows through the state; most of the rivers finally empty into the Río Grande. Temperatures in some canyons in the state reach over 100 °F in the summer while the same areas rarely drop below 32 °F in the winter. Microclimates found in the heart of the Sierra Madre Occidental in the state could be considered tropical, and wild tropical plants have been found in some canyons. La Barranca del Cobre, or Copper Canyon, a spectacular canyon system larger and deeper than the Grand Canyon; the canyon also contains Mexico's two tallest waterfalls: Basaseachic Falls and Piedra Volada. There are two national parks found in the mountainous area of the state: Cumbres de Majalca National Park and Basaseachic Falls National Park.
Title: Grand Canyon
Passage: 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.
Grand Canyon Imperial Valley