|

About the grand canyon
The Grand Canyon
is a steep-sided gorge carved by the Colorado River in the United
States in the state of Arizona. It is largely contained within the
Grand Canyon National Park — one of the first national parks in the
United States. President Theodore Roosevelt was a major proponent of
preservation of the Grand Canyon area, and visited on numerous
occasions to hunt and enjoy the scenery.
Scientific
discovery's
Longstanding scientific consensus has been that the
canyon was created by the Colorado River over a six
million year period. The canyon is 277 miles (446
km) long, ranges in width from 4 to 18 miles (6.4 to
29 km) and attains a depth of over a mile (1.83
km)(6,000 feet).[1]
Nearly two billion years of the Earth's 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. The "canyon began in the west, followed by
another that formed in the east. Eventually, the two
broke through and met as a single majestic rent in
the earth some six million years ago. [...] The
merger apparently occurred where the river today
bends to the west, in the area known as the Kaibab
Arch."[2]
The Early times in the
Grand Canyon
Before
European immigration, the area was inhabited by Native Americans who
built settlements within the canyon and its many caves. The Pueblo
people considered the Grand Canyon ("Ongtupqa" in Hopi language) a
holy site and made pilgrimages to it. The first European known to
have viewed the Grand Canyon was García López de Cárdenas from
Spain, who arrived in 1540.[3]
In 1869, Major John Wesley Powell, a one-armed Civil War veteran,
made the first recorded journey through the canyon on the Colorado
River. Powell referred to the sedimentary rock units exposed in the
canyon as "leaves in a great story book.
The Geography of The grand canyon
The
Grand Canyon is a massive rift 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. The Grand Canyon is unmatched
throughout the world for the vistas it offers to
visitors on the rim. It is not the deepest canyon in
the world — Cotahuasi Canyon (11598 feet or 3535 m)
and Colca Canyon (10,499 feet or 3,200 m), both in
Arequipa, Peru, and Hells Canyon (7,993 feet or2436
m) on the Oregon-Idaho border, are all deeper but
Grand Canyon is known for its overwhelming size and
its intricate and colorful landscape. Geologically
it is significant because of the thick sequence of
ancient rocks that are beautifully preserved and
exposed in the walls of the canyon. These rock
layers record much of the early geologic history of
the North American continent.
Information obtained
at www.wikipedia.org/wiki/Grand_Canyon
|