We decided, for our Science Project, that we would learn about the Grand Canyon
and its layers. It is located in Arizona and is one of the greatest natural
wonders of the world that is around eighteen miles wide and nearly 280 miles
long. The width and depth of the Canyon vary from place to place. At the South
Rim, near Grand Canyon Village, it’s a vertical mile, which is about 5000 feet
from rim to river. The width of the Canyon at Grand Canyon Village is 10 miles
from rim to rim; though in places it is as much as 18 miles wide. Another way to
look at the enormous size is by the time a trip takes. From the bottom of the
Canyon and back on foot is a two-day journey. Rim-to-rim hikers generally take
three days one-way to get from the North Rim to the South Rim. A trip through
Grand Canyon by raft can take two weeks or longer and experienced backpackers
have spent weeks in the more remote areas of the Canyon. In 1975 the park was
nearly doubled in size by the inclusion of Grand Canyon National Monument and
Marble Canyon National Monument and portions of Glen Canyon and Lake Mead
national recreation areas. The effects of tourism and federal water management
policies led the government to take steps to protect the canyon’s environment
during the 1990s. In March 1996 a controlled flood through Glen Canyon Dam was
generated as a way to re-create natural spring flooding through the canyon. The
results of this led to a new water-management plan. This plan incorporates
flooding to restore the canyon’s natural ecosystems, which had been changed by
the construction of Glen Canyon Dam in 1963. In 1997 the government restricted
small planes and helicopters from flying over the canyon and was considering
other ways to limit the effects of tourism on the park. The sites of the park
are incredible with its beauty and mystery. One of the main attractions is the
Colorado River, which is about 242,000 square miles of land ranging from the
states of Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada and California.
From here, at an altitude of 9,010 feet, the Colorado begins it's flow
southwestward toward the Gulf o f California and the Pacific Ocean. By the time
the river enters the Grand Canyon, at Lee’s ferry, its altitude has fallen to
3,110 feet, dropping over one mile since its beginning. The river will drop
another 2,200 feet before it reaches the other end of the Grand Canyon, the
Grand Wash Cliffs 277 miles away. The park itself includes over a million acres
of land 1,218,375.54 acres. The Grand Canyon has been sculpted in general by the
downward cutting of the Colorado River, which flows through the canyon's lowest
portions. Other factors have also played a part. The Kaibab Plateau, which forms
the northern rim of the canyon, is about 1200 ft higher than the Coconino
Plateau, which forms the southern rim. Water from the northern side has flowed
into the canyon, forming tributary valleys, while the streams of the southern
plateau flow away in a southerly direction without carving valleys in the canyon
walls. The underlying rock beds also have a southwestern slant, with the result
that groundwater from the north finds its way into the canyon, but water from
the south does not. In the entire canyon region, jointing and faulting has
broken the rocks, and fractures in the rocks resulting from these processes have
contributed to the rapid erosion of the gorge. Being named a national monument
in 1906 by Theodore Roosevelt first protected this park. A famous quote by
Roosevelt was he proclaimed it to be “the most impressive piece of scenery I
have ever looked at”. Congress named it a National Park in 1919. Back in 1869,
when Major John Wesley Powell led the first expedition through Grand Canyon, he
used wooden boats. Although they were not a very good design, they worked, and
for seventy years, those who followed Powell’s route experimented with
different designs and techniques, refining to a science the art of rowing wooden
boats in whitewater. The extreme variations in elevation from the depths of the
canyon to the northern rim create four distinct zones of climate and plant life.
Dense virgin forests of aspen, pine, fir, and spruce grow on the colder northern
rim. The southern rim though, is sparsely covered with piñon and juniper.
Wildlife includes deer, antelope, cougar, and mountain sheep. Prehistoric Native
American groups lived in the canyon and on its rims; ruins of pueblos and cliff
dwellings remain. The park is bordered on the south by the reservation of the
Havasupai people. In 1990 3,752,901 people attended and were down -5.4%. In 1991
3,905,989 went and were up 4.1%. In 1992 4,547,027 people visited and were
record with a 16.4% increase. In ‘93 4,928,509 visited and were up 8.4%. In
1994 4,704,070 people attended and went down 4.6%. Then in 1995 4,908,073 people
went to the park and were an increase of 4.4%. In 1996 4,730,682 people attended
and went down 3.6%. In ‘97 4,851,931 people came and it went up 2.6%. Finally
in 1998 4,578,089 people came and made a 5.6% decrease from the year before. By
using the charts we concluded that the temperatures at the Inner Canyon were
much hotter than the ones on the South Rim. The inner part had a high
temperature of about 110 degrees and a low temperature of about 37 degrees. The
southern rim had a high temperature of 85 degrees while the low was about 20
degrees. Our main problem was to find the layers of the Grand Canyon. With much
research we discovered all the layers with their exact time formations. We also
found out the colors of the layers, which got lighter as it went higher in
elevation. In a typical section of the canyon, toward its eastern end, nine
separate rock layers can be seen, piled vertically like a stack of pancakes. The
topmost layer is a limestone, the Kaibab limestone. Below this layer is a thick
depositing of sandstone, called the Coconino sandstone, and below that a layer
of soft, shaly rock known as the Hermit shale. Still lower is a series of shales
and sandstones interbedded with each other, collectively termed the Supai
formation. The fossils found in the Supai and the rocks above it suggest that
these rocks were all deposited in the Permian Period, at the end of the
Paleozoic Era, from 225 million to 280 million years ago. However, the Supai may
be slightly older still. Next comes a deposit of light gray-blue limestone, the
Redwall limestone, which in many places has been colored red by seepage from the
Supai beds above. The Redwall is 152 m (500 ft) thick and is easily identified
because of the prominent sheer cliffs that it forms in the canyon walls. This
layer has been identified as belonging to the Mississippian Period (360 million
to 330 million years ago). A thin layer of sandstone, the Temple Butte, beneath
the Redwall, gives evidence of having originated in the Devonian Period (410
million to 360 million years ago). The next three rock layers, consisting of the
brown Muav limestone, the green Bright Angel shale, and the Tapeats sandstone,
all belong to the Cambrian Period (570 million to 500 million years ago), at the
dawn of the Paleozoic Era. Beneath these layers, at the bottom of the canyon,
are the most ancient rocks of all, Precambrian schists and gneisses, from half a
billion to a billion years old. So after all this work, what have we learned? We
have learned that the Grand Canyon is one of the greatest natural formations in
the world. It is not one big smooth canyon, but rather thousands of differently
detailed rocks and ledges. The sight of the magnificent park is unmatched with
any other. It has thousands of millions of different colors, which are beautiful
and spectacular. From the bright morning sun to the evening of a rainbow sunset,
the Grand Canyon has a lovely view no matter what time of day. The rocks and
plants reflect the rays of the sun like the glittering evening ocean. The
Colorado River stretches for thousands of miles and can be seen from almost any
part of the park. From the desert type summer weather to the freezing Snow
Mountains of winter, the appearance of the canyon is different throughout the
whole year. We were glad that we chose the Grand Canyon as our project because
it has proved to be very interesting and exciting to learn about. We learned a
great amount of information on this park and it taught us a lot about nature and
how the Grand Canyon came to be.

Bibliography
“Charts of Canyon” http://highsonoran.com/tempcharts.html “Overall
facts about the Canyon” http://www.nps.gov/grca/facts/index.htm “Grand
Canyon Graphs” http://www.pbs.org/kuat/grandcanyontlood/graphs.html Foster,
Lynn. Exploring the Grand Canyon. Baltimore : Grand Canyon Association. 1990
Schmidt, Jeremy. Grand Canyon National Park (Natural History Guide) Florida :
Houghton Mifflin Co. 1993. Way, Thomas E. Destination : Grand Canyon. New York :
Golden West Publisher. 1990. Whitney, Stephen R. A Field Guide to the Grand
Canyon New York : Mountaineers Books. 1996.