What Is a Cliff?
The word cliff is derived from an old English word “clif” which refers to a near vertical or extremely vertical rock exposed from the surface. The main processes through which cliffs are formed are erosion, weathering, and tectonic activity. Cliffs are a common feature on the coastal lines, mountainous regions, escarpments, and along the river banks. Scientists have established that as the cliff agents invade an area, some rocks known as the sedimentary rocks become resistant to weathering. They are, therefore, left protruding vertically leading to the formation of a cliff. An outstanding feature of a cliff is a scree slope found in the base. A cliff can be big enough to form a mountain and some of the largest cliffs are found underwater in the sea
How Are Cliffs Formed?
Cliff formation is catalyzed by various agents. The major sedimentary rocks that form a cliff are dolomite, sandstone, and limestone. Types of igneous rocks which form cliffs include granite and basalt. The major processes involved in the formation of a cliff are discussed below.
Water and Erosion
A point of weakness is created when waves from the sea hit the land leading to a cut known as a notch. The notch erodes further resulting into a cave. The cave develops hallows along the land leading to a mass of hard rock. With time, more erosion takes place making the overhanging hard part of the cave to collapse into the sea. The sea water washes away the fallen part leading to the formation of a cliff. Continuous erosion and weathering cause the cliff to enlarge and retreat more into the land. Continuous lapping of water against the adjacent rocks leads to the formation of a vertically cut feature. Over thousands of years, only the very hard rocks are left standing, either vertically or sloping. The process leads to the formation of both huge and small cliffs.
Cliffs are also formed along a river. As the river water flows with velocity, the water begins cutting the earth. Cliff walls are consequently formed on either side of the river like the Grand Canyon. During the rainy season, when water levels are higher, the speed of water increases leading to expansion of the cliff.
Formation By Glaciers
Though the process took place a long time ago, it is believed that some cliffs were formed from glaciers. During the ice age, glacier covered the earth. With global warming, the glacier began moving across the earth. Due to the great weight and velocity the glacier, it formed some depressions as it flowed across the globe. Expansive cliffs were therefore created since glaciers have tremendous weight. Such cliffs are scattered with rock outcroppings as the main feature. Glaciers lead to the formation of triangularly shaped cliffs which are broad hence known as truncated spurs.
Formation of a Cliff Through Tectonic Activity
Below the earth surface, there are huge tectonic plates. The plates shift from time to time. In case two plates come into contact with each other, huge pressure is created forcing one of the plates to move upwards and protrude. Though the process may take time, mountains and cliffs are created. When the tectonic plates meet and exert extreme pressure on each other, we may experience earthquakes leading to tears on the earth surface. The wears and tears can be extreme enough to form a cliff.
Formation From Escarpments
An escarpment is a common type of cliff that arises out of the movement of a geologic fault or occurrence of a landslide. Some rocks of different hardness may become incompatible leading to differential erosion of the layers. Such erosion will lead to the formation of a cliff. With time wearing-off occurs through agents such as water or wind leading to one side being more eroded than the other. Coastal cliffs can also be classified as steep escarpments that form when the sea levels rise.
Large and Famous Cliffs in the World
Though some of the most massive cliffs are underwater, there are various cliffs that are found on the land and attract huge attention from researchers. The Nanga Parbat’s Rupal face is known to be a large cliff at 15,000 feet (4,600 meters) from the base. The eastern side of the Great Trango in Karakoram Mountain in Pakistan is also a large cliff. At 1,300 meters high, the cliff has a vertical elevation made of two pillars stacked on each other. In Europe, the highest cliff is the Troll wall, located in Norway. The cliff is famous for jumpers due to the vertical inclination. The Kalaupapa cliff in Hawaii in the USA is also considered a large cliff. With 1,010 meters vertical wall, the cliff is a major tourist attraction site since it measures 2000 feet above the Pacific Ocean. The Mitre Peak has the north face side as a major cliff. At 1,683 meters high the cliff drops to Milford Sound in New Zealand. The most dramatic vertical drop of a cliff is found on Mount Thor. Located on Baffin Island in Arctic Canada, the cliff stands at 1370 meters (4500 feet). The cliff is famous for the overhanging section at the top measuring 480 meters (1600 feet). The vertical drop of the Mount Thor is at 1,250 meters (4,100 feet). Astronomers have discovered that the highest cliff in our solar system is Verona Rupes, measuring more than 20 kilometers (12 miles) high. The cliff is located on a moon of the Uranus planet on Miranda.
Importance Of Cliffs
A cliff can act as a tourist attraction. Some cliffs offer a habitat for plants and animals. Some birds nest in the cliffs due to the absence of predators in such rugged landscapes. It has been observed that the outlook of cliffs change with time as the weathering process continues. Natural occurrences such as earthquake and heavy rains such as the El Nino lead to the advancement of a cliff. Mining can be carried on cliffs since some contain precious rare minerals like marble. The landscapes of major cliffs, especially along the coast, have evolved organically enabling human adaptations. The result is the evolution of a land management system that is sustainable and incorporates biological diversity.