Class: 1C Date: 30th August 1998
ccording to the encyclopedia, The Grand Canyon is an exceptionally deep, steep-walled canyon in northwestern Arizona, excavated by the Colorado River. It is about 446 km long, up to 29 km wide, and more than 1500 m deep. The entire canyon is extremely beautiful, containing towering buttes, mesas, and valleys within its main gorge. A spectacular section of the canyon, together with plateau areas on either side of it, are preserved at the Grand Canyon National Park, which receives about four million visitors a year.
he Grand Canyon cuts steeply through an arid plateau region that lies between about 1500 and 2700 m above sea level. This region, although lacking year-round streams in recent years, is sharply eroded, showing such characteristic forms as buttes; it is interspersed with old lava flows, hills composed of volcanic debris, and intrusions of igneous rock. The plateau area has a general downward slope to the southwest and in its upper reaches is sparsely covered with such evergreens as juniper and piñon. Parts of the northern rim of the canyon are forested. Vegetation in the depths of the valley consists principally of such desert plants as agave and Spanish bayonet. In general the entire canyon area has little soil. The climate of the plateau region above the canyon is severe, with extremes of both heat and cold. The canyon floor also becomes extremely hot in summer, but seldom experiences frost in the wintertime.
he 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 365 m 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, the rocks have been broken by jointing and faulting, and fractures in the rocks resulting from these processes have contributed to the rapid erosion of the gorge.
fter this fieldtrip, I hope to learn more about the history and geography of the Grand Canyon.
istory: The explorers of the canyon and the interesting events which happened at the canyon.
eography: I hope to learn more about the rocks of The Grand Canyon and it’s nine separate rock layers ( from the topmost layer to the bottom layer)