|
What is the Geologic History of the
Grand Canyon?
These 1900 square miles of rock architecture
make up one of the most unique geological areas
on the face of the earth. There are really two
separate geologic stories. The first story is
older than Grand Canyon history itself as the
rocks provide evidence dating to the Paleozoic
Era (550--250 million years ago) and scattered
remnants of Precambrian era (2000 million years).
There is a missing 225 million years of Grand
Canyon history since Kaibab limestone was laid
down, washed away by rain and carried to the
delta by the Colorado River. Also missing are
the 65 million years of the recent Cenozoic
era; the missing records are indicated in the
history of the nearby Vermillion Cliffs rock
and the the staircase plateaus of southern Utah
which do show these geologic features.
The second story is about how the Grand Canyon
came into existence.
When and how was the Grand Canyon created?
The canyon itself is believed to have been
created in the past five to six million years,
which is recent compared to the age of the rock.
The simple answer for its creation is erosion
by the Colorado River, which continues to shape
the canyon today along with rain, snowmelt,
and feeder streams running through it. Though
the canyon is semi-arid, the storms that do
occur are sudden and violent.
What gives the rock its distinctive
colors and shapes?
Different rock layers have different responses
to erosion:
Some
form slopes
Some
form cliffs
Some
erode more quickly than others
The shadings of color are due to minerals imparting
tones of red, yellow, and green. Because of
the limited rainfall, vegetation is scarce,
leaving the rock exposed instead of covered
with lush green color.
Does the Grand Canyon have the oldest
exposed rock in the world?
No, the oldest exposed rocks at the canyon
are 2 billion years old. The oldest rocks in
the world are nearly 4 billion years old.
How big is it?
It has over a million acres of land covering
1904 square miles. In river miles, it runs 277
miles beginning at Lees Ferry and ending at
Grand Wash Cliffs. It's deepest point is 6,000
feet. The elevations are from 1200 to 9100 feet.
How did the Grand Canyon become a National
Park?
Mining settlements developed along the rim
in the 1880s, but residents soon saw that tourism
would become more profitable than mining. In
1893 it became protected as a National Forest
Reserve and later as a National Monument. It
received park status in 1919, three years after
the National Park Service was established. The
mission of the National Park Service is to preserve
the park and all of its features, including
the processes that created them, and to provide
for it's enjoyment by park visitors in a way
that will leave the canyon unspoiled for future
generations.
What is the human history of the Grand
Canyon?
The earliest inhabitants came 11,000 years
ago, Paleo-Indians who crossed an ancient land
bridge over the Bering Strait. These ancient
people were hunters of large prehistoric elephants,
mastodons, and mammoths. About 1500 years ago,
the Anasazi arrived in the area, leaving evidence
of more than 2,000 sites. The latest Native
American group to occupy the region were Navajos.
Europeans arrived with the Spanish Conquistadors,
who were more interested in gold than the canyon.
The first record of an American expedition was
an army survey party seeking a new supply route,
which resulted in disappointment. However, in
1869 John Wesley Powell created national interest
with his famous trip down the Colorado River.
Recreational Development History
In the early days, tourists made the trip by
stagecoach. Then in 1901 a railway was developed
from Williams, Arizona to the South Rim. By
1905 the El Tovar Grand Hotel was built on the
canyon's edge. The area was further developed
by The Fred Harvey Company, who was hired to
make the Grand Canyon experience enjoyable for
visitors. They hired Mary E. Colter as an interior
decorator, whose contribution of blending manmade
structures into the landscape continues in park
philosophy today. Today Xanterra Parks &
Resorts is the primary concessionaire on the
South Rim, and they continue in the Fred Harvey
tradition of fine hospitality.
Fauna History
The park is home to 75 species of mammals,
24 types of lizards, 24 kinds of snakes, and
300 species of birds. The Kaibab squirrel with
its white tail and tufted ears is native only
to the North Rim. The pink rattlesnake is found
only at lower elevations in the canyon. For
fossils records, visit the Kaibab Formation
beds near Bright Angel Lodge. You'll find dozens
of different kinds of fossils exposed on the
trail.
You can stand at the edge and think about gazing
over 2 billion years of history, but most likely
you will simply lose your breath lost in the
inconceivable beauty of nature's creation.
|
