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#2551 2025-08-03 16:54:50

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 51,261

Re: Miscellany

2351) River Nile

Gist

The River Nile, which runs through several countries in East and North Africa, is regarded as the longest river on Earth, running nearly 6,700 kilometers from its source in Lake Victoria to its mouth in the Mediterranean.

The Nile River's depth varies, but it generally ranges from 26 to 36 feet (8 to 11 meters) deep on average. While some parts of the river, like Lake Victoria (a source of the Nile), can be much deeper, with maximum depths of up to 273 feet, the main river channel is typically within that 26-36 foot range, according to A-Z Animals.

The Nile River is estimated to be 30 million years old, according to a study published in Nature Geoscience. This is significantly older than previous estimates, which placed its age at around 6 million years. Scientists discovered that the Nile's unique path is linked to the movement of rock in the Earth's deep mantle, which has kept it flowing in the same general direction for millions of years

Summary

The Nile is a river in Africa. It is the longest river on Earth (about 6,650 km or 4,132 miles), though other rivers carry more water.

Its longest section starts in Lake Victoria, and flows into the Mediterranean Sea near Alexandria.

This longest part is called the White Nile. It flows from Lake Victoria in Uganda, and through Sudan to Khartoum. There it is joined by the Blue Nile to form the Nile proper, which then flows through Egypt. The Blue Nile comes from Ethiopia near the Red Sea. The two branches meet near Khartoum, in Sudan. About 300 million cubic metres of water flow down the Nile each day.

The Nile is essential to the drier countries in the north of Africa. On the Nile there are many boats: it is one of the easiest ways to get around. Historically, most cities in Egypt are built next to the river, and the pyramids are close to the Nile. The Nile has always provided most of the water used to grow crops in Egypt: much of the rest of the country is a desert. In ancient times the Nile flooded every year and the people would starve if there was not enough water for the crops. The Ancient Egyptians got papyrus from the Nile to write on. Papyrus is made from a plant which grows near the Nile.

Many different types of animals live in or near the waters of the Nile, including crocodiles, birds, fish and many others. Not only do animals depend on the Nile for survival, but also people who live there need it for everyday use like washing, as a water supply, keeping crops watered and other jobs.

Pyramids were built close to the Nile because they needed the granite stones from Aswan to be transported by barges down the Nile.

Details

The Nile River flows over 6,800 kilometers (4,000 miles) before emptying into the Mediterranean Sea. For thousands of years, the river has provided a source of irrigation to transform the dry area around it into lush agricultural land. Today, the river continues to be a vital freshwater resource for millions of northeast Africans who rely on it for irrigation, drinking water, fishing, and hydroelectric power.

Even today, families come to the banks of the Nile River to gather water for their day, against the backdrop of ancient Egyptian ruins.

The Nile River, the longest river in the world, flows from south to north through northeastern Africa. It begins in the rivers that flow into Lake Victoria (located in modern-day Kenya, Tanzania and Uganda) and travels more than 6,800 kilometers (4,000 miles) to the north, emptying into the Mediterranean Sea on Egypt’s coast. The river’s three main tributaries are the Atbara, the Blue Nile and the White Nile. The entire Nile River basin—made up of interconnected streams, lakes and rivers—threads its way through 11 African countries: Burundi, Democratic Republic of the Congo, Egypt, Eritrea, Ethiopia, Kenya, Rwanda, South Sudan, Sudan, Tanzania and Uganda.

The Nile River was critical to the development of ancient Egypt. The soil of the Nile River Delta between Cairo, Egypt and the Mediterranean Sea is rich in nutrients, due to the large silt deposits the Nile leaves behind as it flows into the sea. The banks of the Nile all along its vast length contain rich soil as well, thanks to annual flooding that deposits silt. From space, the contrast between the Nile's lush green river banks and the desert through which it flows is obvious.

For millennia, much of Egypt's food has been cultivated in the Nile Delta region. Ancient Egyptians developed irrigation methods to increase the amount of land they could use for crops to support a thriving population. Beans, cotton, flax and wheat were important, abundant crops that could be easily stored and traded.

The Nile River Delta was also an ideal growing location for the papyrus plant. Ancient Egyptians used the papyrus plant in many ways, such as making cloth, boxes and rope, but by far its most important use was in making paper. Besides using the river's natural resources for themselves and trading them with others, early Egyptians also used the river for bathing, drinking, recreation and transportation. Today, National Geographic Explorer Raghda (Didi) El-Behaedi studies how ancient societies responded to a shrinking water supply, particularly focusing on Lake Moeris and the Nile. Informed by technologies such as remote sensing and GIS, El-Behaedi seeks to better understand ancient landscapes and subsequently bolster cultural heritage preservation efforts in Egypt.

Today, 95 percent of Egyptians live within a few miles of the Nile. Canals bring water from the Nile to irrigate farms and support cities. The river's water is a vital resource for millions of people who depend on it for irrigation, drinking water, fishing and hydroelectric power. The river has served as an important transportation route for thousands of years. Today, some residents of Cairo have begun using private speed boats, water taxis or ferries to avoid crowded streets.

Dams, such as the Aswan Dam in Egypt, have been built to help to tame the river and provide a source of hydroelectric power. However, the silt and sediment that used to flow north, enriching the soil and building the delta, is now building up behind the dam. Instead of growing in size through the soil deposits, the delta is shrinking due to erosion along the Mediterranean Sea. In addition, annual flooding no longer occurs along parts of the Nile. These floods were necessary to flush and clean the water of human and agricultural waste. As a result, the water is becoming more polluted.

The many habitats in the Nile River basin support biodiversity in the region. The basin is home to a variety of animals, including the hippopotamus, the monitor lizard and the fearsome Nile crocodile. The Nile River Delta is also a vital winter stopover for millions of birds migrating along the East African flyway.

The rivers and lakes are filled with a variety of freshwater fish, including the sharp-toothed tigerfish and the Nile perch, a large fish that can grow to weigh more than 79 kilograms (175 pounds). Fishing is a way of life for many inhabitants of northeast Africa, who depend on it for food and a way to earn money. Today, however, the Nile River system is threatened by pollution, as it harms the fish and other wildlife that live in its aquatic environment. This pollution is also impacting the people who depend on the Nile for their drinking water and for irrigating their crops.

With so many countries sharing and relying on the interconnected water resource that is the Nile River basin, it is essential for them to cooperate in regard to its use. Unfortunately, these countries do not always agree on how to manage the water supply. One of the countries most impacted by pollution and water shortages is Egypt, which gets 90 percent of its water from the Nile. As the country’s population increases, experts say Egypt’s demand for water may soon exceed its supply. The United Nations predicts that Egypt will face a water shortage by 2025.

This need for cooperation led to the formation of the Nile Basin Initiative (NBI) in 1999. The NBI brings representatives from all 11 countries in the Nile River basin together to discuss ways to manage and share the water. In 2010, one NBI initiative saw four nations—Ethiopia, Rwanda, Tanzania and Uganda—enter into a Nile River water-sharing agreement. The agreement, called the Cooperative Framework Agreement, allows the countries to use the Nile River system in their borders to encourage cooperation and sustainability. Kenya and Burundi later signed onto the agreement, which remains in place today.

There are still disagreements over the management of the Nile's waters. Ethiopia recently built its own dam, the Grand Ethiopian Renaissance Dam, over the Blue Nile tributary. The Blue Nile supplies most of the water that flows into the Nile River. This has created conflict between Ethiopia and the two countries, Egypt and Sudan, that are downriver. Egypt and Sudan depend on the flow of water from the Blue Nile.

The dam, however, is a big benefit to Ethiopia. It will allow all of its citizens to have access to electricity. In 2015, the three "downriver" countries impacted by Ethiopia's dam—Egypt, Ethiopia and Sudan—signed an agreement to cooperate as the dam was built and its reservoir slowly filled. The Grand Ethiopian Renaissance Dam is now Africa's largest dam. It began producing electricity in 2022.

Additional Information

The Nile (also known as the Nile River or River Nile) is an important river in Africa that flows northwards into the Mediterranean Sea. At roughly 6,650 km (4,130 mi) long, it is among the longest rivers in the world. Its drainage basin covers eleven countries: the Democratic Republic of the Congo, Tanzania, Burundi, Rwanda, Uganda, Kenya, Ethiopia, Eritrea, South Sudan, Sudan, and Egypt. It plays an important economic role in the economy of these nations, and it is the primary water source for South Sudan, Sudan and Egypt.

The Nile has two major tributaries: the White Nile and the Blue Nile. The White Nile, being the longer, is traditionally considered to be the headwaters, while the Blue Nile actually contributes 80% of the water and silt below the confluence of the two. The White Nile begins at Lake Victoria and flows through Uganda and South Sudan, while the Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet at the Sudanese capital of Khartoum.

After Khartoum the river flows north, almost entirely through the Nubian Desert, to Cairo and its large delta, joining the Mediterranean Sea at Alexandria. Egyptian civilization and Sudanese kingdoms have depended on the river and its annual flooding since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of the Aswan Dam. Nearly all the cultural and historical sites of Ancient Egypt developed and are found along river banks. The Nile is, with the Rhône and Po, one of the three Mediterranean rivers with the largest water discharge.

More Information

Nile River, the longest river in the world, called the father of African rivers. It rises south of the Equator and flows northward through northeastern Africa to drain into the Mediterranean Sea. It has a length of about 4,132 miles (6,650 kilometres) and drains an area estimated at 1,293,000 square miles (3,349,000 square kilometres). Its basin includes parts of Tanzania, Burundi, Rwanda, the Democratic Republic of the Congo, Kenya, Uganda, South Sudan, Ethiopia, Sudan, and the cultivated part of Egypt. Its most distant source is the Kagera River in Burundi.

The Nile is formed by three principal streams: the Blue Nile (Arabic: Al-Baḥr Al-Azraq; Amharic: Abay) and the Atbara (Arabic: Nahr ʿAṭbarah), which flow from the highlands of Ethiopia, and the White Nile (Arabic: Al-Baḥr Al-Abyad), the headstreams of which flow into Lakes Victoria and Albert.

The name Nile is derived from the Greek Neilos (Latin: Nilus), which probably originated from the Semitic root naḥal, meaning a valley or a river valley and hence, by an extension of the meaning, a river. The fact that the Nile—unlike other great rivers known to them—flowed from the south northward and was in flood at the warmest time of the year was an unsolved mystery to the ancient Egyptians and Greeks. The ancient Egyptians called the river Ar or Aur (Coptic: Iaro), “Black,” in allusion to the colour of the sediments carried by the river when it is in flood. Nile mud is black enough to have given the land itself its oldest name, Kem or Kemi, which also means “black” and signifies darkness. In the Odyssey, the epic poem written by the Greek poet Homer (7th century bce), Aigyptos is the name of the Nile (masculine) as well as the country of Egypt (feminine) through which it flows. The Nile in Egypt and Sudan is now called Al-Nīl, Al-Baḥr, and Baḥr Al-Nīl or Nahr Al-Nīl.

The Nile River basin, which covers about one-tenth of the area of the continent, served as the stage for the evolution and decay of advanced civilizations in the ancient world. On the banks of the river dwelled people who were among the first to cultivate the arts of agriculture and to use the plow. The basin is bordered on the north by the Mediterranean; on the east by the Red Sea Hills and the Ethiopian Plateau; on the south by the East African Highlands, which include Lake Victoria, a Nile source; and on the west by the less well-defined watershed between the Nile, Chad, and Congo basins, extending northwest to include the Marrah Mountains of Sudan, the Al-Jilf al-Kabīr Plateau of Egypt, and the Libyan Desert (part of the Sahara).

The availability of water from the Nile throughout the year, combined with the area’s high temperatures, makes possible intensive cultivation along its banks. Even in some of the regions in which the average rainfall is sufficient for cultivation, marked annual variations in precipitation often make cultivation without irrigation risky.

Al-Jizah. Giza Necropolis, Giza Plateau, Cairo, Egypt. Side view of Sphinx with the Great Pyramid of Khufu (Cheops) rising in the background. The sides of all three of the Giza pyramids are astronomically oriented to be north-south, east-west

The Nile River is also a vital waterway for transport, especially at times when motor transport is not feasible—e.g., during the flood season. Improvements in air, rail, and highway facilities beginning in the 20th century, however, greatly reduced dependency on the waterway.

Physiography of Nile River

It is thought that approximately 30 million years ago the early Nile, then a much shorter stream, had its sources at about 18° to 20° N latitude. Its main headstream may then have been the present Atbara River. To the south lay the vast enclosed drainage system containing the large Lake Sudd. According to one theory on the evolution of the Nile system, about 25,000 years ago the East African drainage to Lake Victoria developed an outlet to the north, which sent its water into Lake Sudd. With the accumulation of sediments over a long period, the water level of this lake rose gradually, and, as a result of the overflow, the lake was drained, spilling over to the north. The overflow waters of Lake Sudd, rapidly forming a riverbed, linked the two major parts of the Nile system, thus unifying the drainage from Lake Victoria to the Mediterranean Sea.

The basin of the present-day Nile falls naturally into seven major regions: the Lake Plateau of East Africa, the Al-Jabal (El-Jebel), the White Nile, the Blue Nile, the Atbara, the Nile north of Khartoum in Sudan and Egypt, and the Nile delta.

The Lake Plateau region of East Africa produces a number of headstreams and lakes that feed the White Nile. It is generally agreed that the Nile has several sources rather than one. The furthest headstream may be regarded as the Kagera River, which rises in the highlands of Burundi near the northern tip of Lake Tanganyika and then flows into Lake Victoria. The Nile proper, however, rises from Lake Victoria, the second largest freshwater lake in the world, which has an area of more than 26,800 square miles and forms a huge but shallow lake. The Nile begins near Jinja, Uganda, on the north shore of the lake, flowing northward over Ripon Falls, which has been submerged since the completion of the Owen Falls Dam (now the Nalubaale Dam) in 1954. The northward stretch of the river, known as the Victoria Nile, enters the shallow Lake Kyoga (Kioga) and, passing through its swamp vegetation, flows out in a westerly direction, descending into the East African Rift System over Murchison (Kabalega) Falls before entering the northern end of Lake Albert. Unlike Lake Victoria, Lake Albert is a deep, narrow lake with mountainous sides. There the waters of the Victoria Nile unite with the lake waters, passing northward as the Albert Nile—a portion of the river, somewhat wider and slower, that is fringed with swampy growth and is navigable for steamers.

The Nile enters South Sudan at Nimule, and from there to Juba—a distance of some 120 miles—it is called the Al-Jabal River or Mountain Nile. This section of the river descends through narrow gorges and over a series of rapids, including the Fula (Fola) Rapids, and receives additional water from short tributaries on both banks; it is not commercially navigable. Below Juba the river flows over a large and very level clay plain, which extends through a narrow valley with hill country on either side, lying some 1,200 to 1,500 feet (370 to 460 metres) above sea level, and through the centre of which flows the main stream. As the gradient of the Nile there is only 1:13,000, the great volume of additional water that arrives during the rainy season cannot be accommodated by the river, and, as a result, during those months almost the entire plain becomes inundated. This circumstance promotes the growth of enormous quantities of aquatic vegetation—including tall grasses and sedges (notably papyrus)—that collectively is called sudd, literally meaning “barrier,” and the region is known as Al-Sudd. These great masses of vegetation, the growth of which is exacerbated by the gentle flow of the water, break off and float downstream, effectively choking the main stream and blocking the navigable channels. Channels have become further choked since the 1950s by the rapid spread of the South American water hyacinth.

This basin receives drainage from numerous other streams. The Al-Ghazāl (Gazelle) River flows in from western South Sudan, joining the Al-Jabal at Lake No, a large lagoon where the main stream takes an easterly direction. The waters of the Al-Ghazāl undergo extensive loss through evaporation, and only a small proportion of them ever reach the Nile. A short distance above Malakal the main stream is joined by the Sobat (Baro in Ethiopia), and downstream from there the river is called the White Nile. The regime of the Sobat is quite different from the steady flowing Al-Jabal, with a maximum flow occurring between July and December; the annual flow of the Sobat is about equal to the water lost through evaporation in Al-Sudd marshes.

The White Nile, about 500 miles in length, supplies some 15 percent of the total volume entering Lake Nasser (called Lake Nubia in Sudan) downstream. It begins at Malakal and joins the Blue Nile at Khartoum, receiving no tributaries of importance. Throughout this stretch the White Nile is a wide placid stream, often having a narrow fringe of swamps. The valley is wide and shallow, thus causing a considerable loss of water by both evaporation and seepage.

The Blue Nile drains from the lofty Ethiopian Plateau, where it descends in a north–northwesterly direction from a height of about 6,000 feet above sea level. Its reputed source is a spring, considered holy by the Ethiopian Orthodox Church, from which a small stream, the Abay, flows down to Lake Tana (T’ana), a fairly shallow lake with an area of about 1,400 square miles. The Abay leaves Lake Tana in a southeasterly direction, flowing through a series of rapids and plunging through a deep gorge. It is estimated that the lake supplies the river with only about 7 percent of its total flow, but this water is important since it is silt-free. The river then flows west and northwest through Sudan to join the White Nile at Khartoum. In the greater part of its course from Lake Tana down to the Sudanese plains, it runs in a canyon that in places is 4,000 feet below the general level of the plateau. All of its tributaries also run in deep ravines. While the White Nile at Khartoum is a river of almost constant volume, the Blue Nile has a pronounced flood season (late July to October) caused by the summer monsoon rains over the Ethiopian Plateau and the rapid runoff from its numerous tributaries; historically, it was this surge that contributed most to the annual Nile floods in Egypt.

The Atbara River, the last tributary of the Nile, flows into the main stream nearly 200 miles north of Khartoum. It rises in Ethiopia at heights of 6,000 to 10,000 feet above sea level, not far from Gonder, to the north of Lake Tana. The two principal tributaries that feed the Atbara are the Angereb (Arabic: Baḥr Al-Salam) and the Tekezē (Amharic: “Terrible”; Arabic: Nahr Satīt). The Tekezē is the most important of these, having a basin more than double the area of the Atbara itself. It rises among the high peaks of the Ethiopian highlands and flows north through a spectacular gorge to join the Atbara in Sudan. For most of its course in Sudan, the Atbara is well below the general level of the plains. Between the plains and the river, the ground is eroded and cut into by gullies formed by water running off the plains after rainfall. The Atbara rises and falls rapidly, like the Blue Nile. In flood it becomes a large, muddy river, and in the dry season it is a string of pools. The Atbara contributes more than 10 percent of the total annual flow of the Nile, but almost all of this comes in the period of July to October.

Along the stretch of the Nile north of Khartoum, which is sometimes called the United Nile, two parts can be distinguished. The first part, which stretches from Khartoum to Lake Nasser, is about 830 miles in length; there the river flows through a desert region where rainfall is negligible, although some irrigation takes place along its banks. The second part includes Lake Nasser—which contains the water held back by the Aswan High Dam in Egypt—and below the dam the irrigated Nile valley and delta region.

Below Khartoum, the Nile flows 50 miles northward until it reaches Sablūkah (Sababka), the site of the sixth and highest cataract. There the river cuts through hills for a distance of eight miles. Flowing northward at Barbar, the river takes an S-bend, in the middle of which, from Abū Ḥamad to Kūrtī and Al-Dabbah (Debba), it flows southwestward for about 170 miles; the fourth cataract is in the middle of this stretch. At the end of this bend, at Dongola, it again resumes a northerly direction, crossing the third cataract and flowing into Lake Nasser.

For the 800 miles from the sixth cataract to Lake Nasser, the riverbed alternates between gentle stretches and series of rapids. Outcropping crystalline rocks that cross the course of the Nile cause the five famous cataracts. Because of these cataracts, the river is not completely navigable, although sections between the cataracts are navigable by sailing vessels and by river steamers.

Lake Nasser, the second largest man-made lake in the world, has a potential maximum area of 2,600 square miles; it inundates more than 300 miles of the Nile’s course, including the second cataract near the border between Egypt and Sudan. Immediately below the high dam is the first cataract, which was once an area of rock-strewn rapids that partially obstructed the flow of the river. From the first cataract to Cairo—a distance of about 500 miles—the Nile flows northward in a relatively narrow flat-bottomed groove, sinuous in outline and generally incised into the underlying limestone plateau, which averages 10 to 14 miles in width and is enclosed by scarps that rise in places to heights of 1,500 feet above the river level. For the last 200 miles of its course before reaching Cairo, the Nile shows a strong tendency to hug the eastern edge of the valley floor, so that the greater part of the cultivated land is found on the left bank.

North of Cairo the Nile enters the delta region, a level triangular lowland. In the 1st century ce the Greek geographer Strabo recorded the Nile as fanning out into seven delta distributaries. The flow has since been controlled and redirected, so that the river now flows across the delta to the sea through two main distributaries, the Rosetta and the Damietta (Dumyāṭ) branches.

The Nile delta, the prototype of all deltas, comprises a gulf of the prehistoric Mediterranean Sea that has been filled in; it is composed of silt brought mainly from the Ethiopian Plateau. The silt varies in its thickness from 50 to 75 feet and comprises the most fertile soil in Africa. It forms a monotonous plain that extends 100 miles from north to south, its greatest east–west extent being 155 miles between Alexandria and Port Said; altogether it covers an area twice that of the Nile valley in Upper Egypt. The land surface slopes gently to the sea, falling some 52 feet from Cairo in a gentle gradient. In the north, on the seaward border, are a number of shallow brackish lagoons and salt marshes: Lake Marout (Buḥayrat Maryūṭ), Lake Edku (Buḥayrat Idkū), Lake Burullus (Buḥayrat Al-Burullus), and Lake Manzala (Buḥayrat Al-Manzilah).

Nile-River-Facts-Image-2.jpg


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#2552 2025-08-04 21:10:26

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 51,261

Re: Miscellany

2352) The Gand Canyon

Gist

The Grand Canyon offers one of the most visible examples of a worldwide geological phenomenon known as the Great Unconformity, in which 250 million-year-old rock strata lie back-to-back with 1.2 billion-year-old rocks. What happened during the hundreds of millions of years between remains largely a mystery.

About 5 million visitors a year visit Grand Canyon National Park to see this immense chasm stretching more than 277 miles long, up to 18 miles wide, which attains a depth of over a mile (6,000 feet).

The Grand Canyon is a massive gorge in northern Arizona, carved by the Colorado River. It's renowned for its layered bands of red rock, revealing millions of years of geological history. The canyon is a popular national park, offering breathtaking views, hiking, and other recreational activities.

Summary

The Grand Canyon in northern Arizona in the United States is one of the most spectacular canyons in the world. It is a 277-mile- (446-kilometer-) long gorge cut through high plateaus by the Colorado River. It is noted for its fantastic shapes and colors. Within the walls of the canyon stand imposing peaks, canyons, and ravines. In general, the color of the canyon is red, but each stratum (a layer of the Earth) or group of strata has a distinctive hue—buff and gray, delicate green and pink, and, in its depths, brown, slate-gray, and violet. The Grand Canyon is an immensely popular tourist destination, with several million visitors per year.

The Grand Canyon extends in a winding course from the mouth of the Paria River, near the northern boundary of Arizona, to Grand Wash Cliffs, near the Nevada line. The canyon ranges in width from about 525 feet (160 meters) to 18 miles (29 kilometers). It reaches a depth of 1 mile (1.6 kilometers) below the rim’s surface. The North Rim, at approximately 8,200 feet (2,500 meters) above sea level, is some 1,200 feet (365 meters) higher than the South Rim. Grand Canyon National Park, which encompasses the Grand Canyon, was established in 1919. Its area was greatly enlarged in 1975 by the addition of adjoining lands so that it now extends from Lake Powell to Lake Mead. Today Grand Canyon National Park covers 1,218,375 acres (493,059 hectares).

The North and South rims of the Grand Canyon are connected by a 215-mile- (346-kilometer-) long highway and by a 21-mile- (34-kilometer-) long trans-canyon trail. Scenic drives and trails lead to all important features. Mule-pack trips and river rafting are popular ways of viewing and experiencing the beauty of the vast canyon. Visitors also can take helicopter and small-plane flights over the canyon or ride a 65-mile (100-kilometer) scenic railway from the city of Williams northward to the South Rim.

The Grand Canyon has many varieties of squirrels, coyotes, foxes, deer, badgers, bobcats, rabbits, chipmunks, and kangaroo rats. Bird species include bald eagles, peregrine falcons, and the rare California condor. Willow trees and cottonwoods grow at the bottom of the canyon where there is plenty of water. There are magnificent forests on the North Rim of the canyon where the soil is moist and deep. There are also drought-resistant plants, including numerous species of cactus.

No other place on Earth compares with the Grand Canyon for its record of geological events. The rocks at the bottom of the canyon date back more than 2.5 billion years. The Grand Canyon was formed through erosion, as the Colorado River wore away rock and cut the canyon. The cutting began about six million years ago, when the river began following its present course. The river’s speed and large volume and such “cutting tools” as sand, gravel, and mud account for its incredible cutting capacity.

Early Native Americans lived in and near the Grand Canyon for several thousand years before Europeans arrived. The national park contains ruins of many ancient villages and cliff dwellings built by the Ancestral Pueblo people. The first sighting of the Grand Canyon by Europeans is credited to the Francisco Coronado expedition of 1540. In the early 1800s trappers examined the canyon, and various expeditions sent by the U.S. government to explore and map the West began to record information about it. In 1869 American geologist and anthropologist John Wesley Powell organized the first party to travel the canyon by boat. By the 1870s extensive reports on the area were being published.

In 1893 President Benjamin Harrison set aside a portion of the canyon area as Grand Canyon Forest Reserve. President Theodore Roosevelt redesignated it a game preserve in 1903 and a national monument in 1908. In 1919 the U.S. Congress officially established Grand Canyon National Park. In 1979 the park was designated a UNESCO World Heritage site.

Details

The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles (446 km) long, up to 18 miles (29 km) wide and attains a depth of over a mile (6,093 feet or 1,857 meters).

The canyon and adjacent rim are contained within Grand Canyon National Park, the Kaibab National Forest, Grand Canyon–Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. President Theodore Roosevelt was a major proponent of the preservation of the Grand Canyon area and visited it on numerous occasions to hunt and enjoy the scenery.

Nearly two billion years of Earth's geological 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. While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago. Since that time, the Colorado River has driven the down-cutting of the tributaries and retreat of the cliffs, simultaneously deepening and widening the canyon.

For thousands of years, the area has been continuously inhabited by Native Americans, who built settlements within the canyon and its many caves. The Pueblo people considered the Grand Canyon 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.

Geography

The Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, and it is also one of the six distinct physiographic sections of the Colorado Plateau province. Even though it is not the deepest canyon on land in the world (Kali Gandaki Gorge in Nepal is much deeper), the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon. These rock layers record much of the early geologic history of the North American continent.

Uplift associated with mountain formation later moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has also resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid. The uplift of the Colorado Plateau is uneven, and the Kaibab Plateau that the Grand Canyon bisects is over one thousand feet (300 m) higher at the North Rim than at the South Rim. Almost all runoff from the North Rim (which also gets more rain and snow) flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon (following the general tilt). The result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side.

Temperatures on the North Rim are generally lower than those on the South Rim because of the greater elevation (averaging 8,000 feet or 2,400 meters above sea level). Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon (State Route 67) is limited during the winter season due to road closures.

Geology

The Grand Canyon is part of the Colorado River basin, which has developed over the past 70 million years. For more than 150 years, scientists have gathered data, proposed new ideas, and debated sometimes contentious theories about the geologic origins of the Grand Canyon and the Colorado River. Formation of the Grand Canyon and the Colorado River may involve a complex history in which multiple factors and geologic processes have interacted over time and in different locations.

In the most recent round of "old river" vs. "young river" controversy, researchers have challenged estimates that had placed the age of the canyon at 5–6 million years. The research has aroused considerable controversy because it suggests a substantial departure from prior widely supported scientific consensus.

In a 2008 study, Victor Polyak examined caves near the Grand Canyon and placed their origins about 17 million years ago. The study, which was published in the journal Science in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon.

In another 2008 study, Rebecca Flowers reported on apatite (U-Th)/He thermochronometry results suggesting that parts of the Grand Canyon had reached a depth near to the modern depth around 20 million years ago. In a subsequent study published in the journal Science in 2012, she suggested that the western part of the Grand Canyon could be as old as 70 million years.

The emerging scientific consensus is that the canyon is made up of multiple segments which formed at different times and eventually connected to become the waterway now traversed by the Colorado River. Of the three central segments, the "Hurricane" was formed 50–70 million years ago, and the "Eastern Grand Canyon" was cut 15–25 million years ago. In contrast, the "Marble Canyon" and "Westernmost Grand Canyon" segments at the ends of the canyon were carved in the last five to six million years.

The major geologic exposures in the Grand Canyon range in age from the two-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 270-million-year-old Kaibab Limestone on the Rim. Within that there is a gap, the Great Unconformity, between 1.75 billion and 1.25 billion years ago for which no deposits are present.

Then, between 1.25 billion and 730 million years ago, intermittent sediments began to form the Grand Canyon Supergroup. Many of the formations were deposited in warm shallow seas, near-shore environments (such as beaches), and swamps as the seashore repeatedly advanced and retreated over the edge of a proto-North America. Major exceptions include the Permian Coconino Sandstone, which contains abundant geological evidence of aeolian sand dune deposition. Several parts of the Supai Group also were deposited in non-marine environments.

The great depth of the Grand Canyon and especially the height of its strata (most of which formed below sea level) can be attributed to 5,000–10,000 feet (1,500–3,000 m) of uplift of the Colorado Plateau, starting about 65 million years ago (during the Laramide orogeny). This uplift has steepened the stream gradient of the Colorado River and its tributaries, which in turn has increased their speed and thus their ability to cut through rock.

Weather conditions during the ice ages also increased the amount of water in the Colorado River drainage system. The ancestral Colorado River responded by cutting its channel faster and deeper.

The base level and course of the Colorado River (or its ancestral equivalent) changed 5.3 million years ago when the Gulf of California opened and lowered the river's base level (its lowest point). This increased the rate of erosion and cut nearly all of the Grand Canyon's current depth by 1.2 million years ago. The terraced walls of the canyon were created by differential erosion.

Between 100,000 and 3 million years ago, volcanic activity deposited ash and lava over the area, which at times completely obstructed the river. These volcanic rocks are the youngest in the canyon.

Additional Informtion

Grand Canyon, immense canyon cut by the Colorado River in the high plateau region of northwestern Arizona, U.S., noted for its fantastic shapes and coloration. The U.S. Congress officially established Grand Canyon National Park in 1919 and in 1979 the park was designated a UNESCO World Heritage site. It is an immensely popular tourist destination, with several million visitors per year.

The Grand Canyon lies in the southwestern portion of the Colorado Plateau, which occupies a large area of the southwestern United States and consists essentially of horizontal layered rocks and lava flows. The broad, intricately sculptured chasm of the canyon contains between its outer walls a multitude of imposing peaks, buttes, gorges, and ravines. It ranges in width from about 175 yards (160 meters) to 18 miles (29 km) and extends in a winding course from the mouth of the Paria River, near Lees Ferry and the northern boundary of Arizona with Utah, to Grand Wash Cliffs, near the Nevada state line, a distance of about 277 miles (446 km); the first portion of the canyon—from Lees Ferry to the confluence with the Little Colorado River—is called Marble Canyon. The Grand Canyon also includes many tributary side canyons and surrounding plateaus.

The greatest depths of the Grand Canyon lie more than a mile (some 6,000 feet [1,800 meters]) below its rim. The deepest and most spectacularly beautiful section, 56 miles (90 km) long, is within the central part of Grand Canyon National Park, which encompasses the river’s length from Lake Powell (formed by Glen Canyon Dam in 1963) to Lake Mead (formed by Hoover Dam in 1936). The North Rim, at approximately 8,200 feet (2,500 meters) above sea level, is some 1,200 feet (365 meters) higher than the South Rim. In its general color, the Grand Canyon is red, but each stratum or group of strata has a distinctive hue—buff and gray, delicate green and pink, or, in its depths, brown, slate-gray, and violet.

Geologic history

Although its awesome grandeur and beauty are the major attractions of the Grand Canyon, perhaps its most vital and valuable aspect lies in the time scale of Earth history that is revealed in the exposed rocks of the canyon walls. No other place on Earth compares to the Grand Canyon for its extensive and profound record of geologic events. The canyon’s record, however, is far from continuous and complete. There are immense time gaps; many millions of years are unaccounted for, owing to gaps in the strata that resulted either from vast quantities of materials being removed by erosion or because there was little or no deposition of materials. Thus, rock formations of considerably different ages are separated by only a thin distinct surface that reveals the vast unconformity in time.

Briefly summarized, the geologic history of the canyon strata is as follows. The crystallized, twisted, and contorted unstratified rocks of the inner gorge at the bottom of the canyon are Archean granite and schist more than 2.5 billion years old. Overlying those very ancient rocks is a layer of Proterozoic limestones, sandstones, and shales that are more than 540 million years old. On top of them are Paleozoic rock strata composed of more limestones, freshwater shales, and cemented sandstones that form much of the canyon’s walls and represent a depositional period stretching over 300 million years. Overlying those rocks in the ordinary geologic record should be a thick sequence of Mesozoic rocks (about 250 to 65 million years old), but rocks dating from the Mesozoic Era in the Grand Canyon have been entirely eroded away. Mesozoic rocks are found nonetheless in nearby southern Utah, where they form precipitous butte remnants and vermilion, white, and pink cliff terraces. Of relatively recent origin are overlying sheets of black lava and volcanic cones that occur a few miles southeast of the canyon and in the western Grand Canyon proper, some estimated to have been active within the past 1,000 years.

The cutting of the mile-deep Grand Canyon by the Colorado River is an event of relatively recent geologic history that began not more than six million years ago, when the river began following its present course. The Colorado River’s rapid velocity and large volume and the great amounts of mud, sand, and gravel it carries swiftly downstream account for the incredible cutting capacity of the river. Before Glen Canyon Dam was built, the sediments carried by the Colorado River were measured at an average of 500,000 tons per day. Conditions favourable to vigorous erosion were brought about by the uplift of the region, which steepened the river’s path and allowed deep entrenchment. The depth of the Grand Canyon is the result of the cutting action of the river, but its great width is explained by rain, wind, temperature, and chemical erosion, helped by the rapid wear of soft rocks, all of which steadily widened the canyon. An experiment was conducted in March 2008, in which water equivalent to about 40 percent of the river’s original flow was released from Glen Canyon Dam for a period of 60 hours to measure the erosion and deposition of sediments along the river. Researchers monitoring the experiment noted additional sand deposition at numerous locations along the river following the release.

The most significant aspect of the environment that is responsible for the canyon is frequently overlooked or not recognized. Were it not for the semiarid climate in the surrounding area, there would be no Grand Canyon. Slope wash from rainfall would have removed the canyon walls, the stair-step topography would long ago have been excavated, the distinctive sculpturing and the multicolored rock structures could not exist, the Painted Desert southeast of the canyon along the Little Colorado River would be gone, and the picturesque Monument Valley to the northeast near the Utah state line would have only a few rounded hillocks.

Terrestrial plant and animal fossils are not abundant in the Grand Canyon’s sedimentary rocks because of the age of the rocks. Fossils are mostly of primitive algae and such marine species as mollusks, corals, trilobites, and other invertebrates.

Animal life in the Grand Canyon area today, however, is varied and abundant. Common mammals are the many varieties of squirrels, coyotes, foxes, deer, badgers, bobcats, rabbits, chipmunks, and kangaroo rats. In addition, the canyon region is home to a great many bird species, including raptors such as bald eagles and peregrine falcons and the rare California condor. Fish species include trout and (in the Little Colorado River) the rare humpback chub (Gila cypha).

Plant life is also varied. In the bottom of the canyon, where temperatures in the summer can reach a high of 120 °F (49 °C), are willows and cottonwoods, which require abundant water during the growing season. Drought-resistant plants include tamarisks, yuccas, agaves, and numerous species of cactus. Efforts have been made to eradicate stands of the invasive tamarisk. On the canyon rims, north and south, there is a wide assortment of plant life. Typical of the South Rim, which receives about 15 inches (380 mm) of precipitation annually, is a well-developed ponderosa pine forest, with scattered stands of piñon pine and juniper. Bush vegetation consists mainly of scrub oak, mountain mahogany, and large sagebrush. On the North Rim, which receives 26 inches (660 mm) of precipitation annually, are magnificent forest communities of ponderosa pine, white and Douglas fir, blue spruce, and aspen. Under less drier conditions the plant life reverts to the desert varieties.

History

Many pueblo and cliff-dweller ruins, with accompanying artifacts, indicate prehistoric occupation. The first sighting of the Grand Canyon by a European is credited to the Francisco Coronado expedition of 1540 and subsequent discovery to two Spanish priests, Francisco Domínguez and Silvestre Vélez de Escalante, in 1776. In the early 1800s trappers examined it, and sundry expeditions sent by the U.S. government to explore and map the West began to record information about the canyon. The first known descent of the river by boat through the canyon was in 1869, during an expedition to the area led by geologist and ethnographer John Wesley Powell. During the 1870s Powell and others conducted subsequent expeditions to the region, and extensive reports on the geography, geology, botany, and ethnology of the area were published.

A portion of the canyon area was set aside as Grand Canyon Forest Reserve by Pres. Benjamin Harrison in 1893, and it was redesignated a game preserve (1903) and national monument (1908) by Pres. Theodore Roosevelt before the U.S. Congress officially established Grand Canyon National Park in 1919. The park’s area was greatly enlarged in 1975 by the addition of adjoining federal and other lands. In 1979 the park was designated a UNESCO World Heritage site. It is an immensely popular tourist destination, with several million visitors per year.

Three Native American reservations (Navajo, Havasupai, and Hualapai) adjoin the Grand Canyon. Kaibab National Forest surrounds the main portion of the national park to the north and south, and Grand Canyon–Parashant National Monument (designated 2000) is north of the western portion of the park, extending westward to the Nevada border. Other public lands near the canyon include Pipe Spring, Rainbow Bridge, and Grand Staircase–Escalante national monuments; Zion National Park; and Glen Canyon and Lake Mead national recreation areas.

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#2553 2025-08-05 21:05:03

Jai Ganesh
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Registered: 2005-06-28
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Re: Miscellany

2353) Desert

Gist

Most experts agree that a desert is an area of land that receives no more than 25 centimeters (10 inches) of precipitation a year. The amount of evaporation in a desert often greatly exceeds the annual rainfall. In all deserts, there is little water available for plants and other organisms.

A desert is any large, extremely dry area of land with sparse vegetation. It is one of Earth's major types of ecosystems, supporting a community of distinctive plants and animals specially adapted to the harsh environment.

Summary

A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the land surface of the Earth is arid or semi-arid. This includes much of the polar regions, where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location.

Deserts are formed by weathering processes as large variations in temperature between day and night strain the rocks, which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting fragments and rubble strewn over the desert floor are further eroded by the wind. This picks up particles of sand and dust, which can remain airborne for extended periods – sometimes causing the formation of sand storms or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing dunes. Other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones, often forming desert pavements, and little further erosion occurs. Other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate. There may be underground water sources in the form of springs and seepages from aquifers. Where these are found, oases can occur.

Plants and animals living in the desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles, and often spines to deter herbivory. Some annual plants germinate, bloom, and die within a few weeks after rainfall, while other long-lived plants survive for years and have deep root systems that are able to tap underground moisture. Animals need to keep cool and find enough food and water to survive. Many are nocturnal and stay in the shade or underground during the day's heat. They tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine. Some animals remain in a state of dormancy for long periods, ready to become active again during the rare rainfall. They then reproduce rapidly while conditions are favorable before returning to dormancy.

People have struggled to live in deserts and the surrounding semi-arid lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, and oases have provided opportunities for a more settled way of life. The cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Desert farming is possible with the aid of irrigation, and the Imperial Valley in California provides an example of how previously barren land can be made productive by the import of water from an outside source. Many trade routes have been forged across deserts, especially across the Sahara, and traditionally were used by caravans of camels carrying salt, gold, ivory and other goods. Large numbers of slaves were also taken northwards across the Sahara. Some mineral extraction also takes place in deserts, and the uninterrupted sunlight gives potential for capturing large quantities of solar energy.

Details

A desert is any large, extremely dry area of land with sparse vegetation. It is one of Earth’s major types of ecosystems, supporting a community of distinctive plants and animals specially adapted to the harsh environment.

Desert environments are so dry that they support only extremely sparse vegetation; trees are usually absent and, under normal climatic conditions, shrubs or herbaceous plants provide only very incomplete ground cover. Extreme aridity renders some deserts virtually devoid of plants; however, this barrenness is believed to be due in part to the effects of human disturbance, such as heavy grazing of cattle, on an already stressed environment.

According to some definitions, any environment that is almost completely free of plants is considered desert, including regions too cold to support vegetation—i.e., “frigid deserts.” Other definitions use the term to apply only to hot and temperate deserts, a restriction followed in this account.

Origin

The desert environments of the present are, in geologic terms, relatively recent in origin. They represent the most extreme result of the progressive cooling and consequent aridification of global climates during the Cenozoic Era (65.5 million years ago to the present), which also led to the development of savannas and scrublands in the less arid regions near the tropical and temperate margins of the developing deserts. It has been suggested that many typical modern desert plant families, particularly those with an Asian centre of diversity such as the chenopod and tamarisk families, first appeared in the Miocene (23 to 5.3 million years ago), evolving in the salty, drying environment of the disappearing Tethys Sea along what is now the Mediterranean–Central Asian axis.

Deserts also probably existed much earlier, during former periods of global arid climate in the lee of mountain ranges that sheltered them from rain or in the centre of extensive continental regions. However, this would have been primarily before the evolution of angiosperms (flowering plants, the group to which most present-day plants, including those of deserts, belong). Only a few primitive plants, which may have been part of the ancient desert vegetation, occur in present-day deserts. One example is the bizarre conifer relative welwitschia in the Namib Desert of southwestern Africa. Welwitschia has only two leaves, which are leathery, straplike organs that emanate from the middle of a massive, mainly subterranean woody stem. These leaves grow perpetually from their bases and erode progressively at their ends. This desert also harbours several other plants and animals peculiarly adapted to the arid environment, suggesting that it might have a longer continuous history of arid conditions than most other deserts.

Ecosystems

Desert floras and faunas initially evolved from ancestors in moister habitats, an evolution that occurred independently on each continent. However, a significant degree of commonality exists among the plant families that dominate different desert vegetations. This is due in part to intrinsic physiologic characteristics in some widespread desert families that preadapt the plants to an arid environment; it also is a result of plant migration occurring through chance seed dispersal among desert regions.

Such migration was particularly easy between northern and southern desert regions in Africa and in the Americas during intervals of drier climate that have occurred in the past two million years. This migration is reflected in close floristic similarities currently observed in these places. For example, the creosote bush (Larrea tridentata), although now widespread and common in North American hot deserts, was probably a natural immigrant from South America as recently as the end of the last Ice Age about 11,700 years ago.

Migration between discrete desert regions also has been relatively easier for those plants adapted to survival in saline soils because such conditions occur not only in deserts but also in coastal habitats. Coasts can therefore provide migration corridors for salt-tolerant plants, and in some cases the drifting of buoyant seeds in ocean currents can provide a transport mechanism between coasts. For example, it is thought that the saltbush or chenopod family of plants reached Australia in this way, initially colonizing coastal habitats and later spreading into the inland deserts.

Environment

Deserts are varied and variable environments, and it is impossible to arrive at a concise definition that satisfies every case. However, their most fundamental characteristic is a shortage of available moisture for plants, resulting from an imbalance between precipitation and evapotranspiration. This situation is exacerbated by considerable variability in the timing of rainfall, low atmospheric humidity, high daytime temperatures, and winds.

Average annual precipitation ranges from almost zero in some South American coastal deserts and Libyan deserts to about 600 millimetres (24 inches) in deserts in Madagascar, although most recognized deserts have an annual rainfall below 400 millimetres. Some authorities consider 250 millimetres the upper limit for mean annual precipitation for true deserts, describing places with a mean annual rainfall of between 250 and 400 millimetres as semideserts. Regions this dry are barely arable and contribute to human food production only by providing grazing lands for livestock.

The arid conditions of the major desert areas result from their position in subtropical regions to either side of the moist equatorial belt. The atmospheric circulation pattern known as the Hadley cell plays an important role in desert climate. In areas close to the Equator, where the amount of incoming solar energy per unit surface area is greatest, air near the ground is heated, then rises, expands, and cools. This process leads to the condensation of moisture and to precipitation. At high levels in the atmosphere, the risen air moves away from the equatorial region to descend eventually in the subtropics as it cools; it moves back toward the Equator at low altitudes, completing the Hadley cell circulation pattern. The air descending over the subtropics has already lost most of its moisture as rain formed during its previous ascent near the Equator. As it descends, it becomes compressed and warmer, its relative humidity falling further. (For further discussion of relative humidity, see biosphere: Humidity.) Hot deserts occur in those regions to the north and south of the equatorial belt that lie beneath these descending, dry air masses. This pattern may be interrupted where local precipitation is increased, especially on the east sides of continents where winds blow onshore, carrying moisture picked up over the ocean. Conversely, deserts may be found elsewhere, as in the lee of mountain ranges, where air is forced to rise, cool, and lose moisture as rain falling on the windward slopes.

Rainfall in deserts is usually meagre. In some cases several years may pass without rain; for example, at Cochones, Chile, no rain fell at all in 45 consecutive years between 1919 and 1964. Usually, however, rain falls in deserts for at least a few days each year—typically 15 to 20 days. When precipitation occurs, it may be very heavy for short periods. For instance, 14 millimetres fell at Mashʾabe Sade, Israel, in only seven minutes on October 5, 1979, and in southwestern Madagascar the entire annual rainfall commonly occurs as heavy showers falling within a single month. Such rainfall usually occurs only over small areas and results from local convectional cells, with more widespread frontal rain being restricted to the southern and northern fringes of deserts. In some local desert showers, the rain falling from clouds evaporates before it reaches the ground. Regions near the equatorial margins of hot deserts receive most of their rain in summer—June to August in the Northern Hemisphere and December to February in the Southern Hemisphere—while those near the temperate margins receive most of their rainfall in winter. Rain is particularly erratic and equally unlikely to occur in all seasons in intermediate regions.

In some deserts that are located near coasts, such as the Namib Desert of southwestern Africa and those of the west coasts of the Americas in California and Peru, fog is an important source of moisture that is otherwise scarce. Moisture droplets settle from the fog onto plants and then may drip onto the soil or be absorbed directly by plant shoots. Dew also may be significant, although not in deserts in from the central parts of continents where atmospheric humidity is consistently very low.

In most desert regions atmospheric humidity is usually too low to permit formation of fog or dew to any significant extent. Potential evaporation rates (the rate of evaporation that would occur if water were continually present) are correspondingly high, typically 2,500 to 3,500 millimetres per year, with as much as 4,262 millimetres potential evaporation per year having been recorded in Death Valley in California. Winds are not unusually strong or frequent in comparison with adjacent environments, but the general lack of vegetation in deserts exacerbates the effect of wind at ground level. Winds can induce the erosion of fine materials and the evaporation of moisture and thereby help determine which plants survive in the desert.

Hot deserts, as their name indicates, experience very high temperatures by day, especially in summer. Absolute maximum air temperatures in all hot deserts exceed 40 °C (104 °F), and the highest value recorded, in Libya, is 58 °C (136.4 °F). The temperature of the soil surface can rise even beyond that of the air, with values as high as 78 °C (172 °F) recorded in the Sahara. However, night temperatures can fall dramatically, because the same lack of cloud cover that admits high levels of incoming solar radiation during the day also allows rapid loss of energy through long-wave radiation to the sky at night. Absolute minimum temperatures, except in desert areas close to the sea, are generally below the freezing point. Typical mean annual temperatures are between 20 °C (68 °F) and 25 °C (77 °F).

Temperate or cold deserts occur in temperate regions at higher latitudes—and therefore colder temperatures—than those at which hot deserts are found. These dry environments are caused by either remoteness from the coast, which results in low atmospheric humidity from a lack of onshore winds, or the presence of high mountains separating the desert from the coast. The largest area of temperate desert lies in Central Asia, with smaller areas in western North America, southeastern South America, and southern Australia. While they experience lower temperatures than the more typical hot deserts, temperate deserts are similar in aridity and consequent environmental features including landforms and soils.

The peculiar climatic environment of deserts has favoured the development of certain characteristic landforms. Stony plains called regs or gibber plains are widespread, their surface covered by desert pavement consisting of coarse gravel and stones coated with a patina of dark “desert varnish” (a glossy dark surface cover consisting of oxides of iron). Rocky, boulder-strewn plateaus cut by dry, usually steep-sided valleys called wadis are also found in deserts in many parts of the world. The local topographic and microclimatic variations produced by this rugged surface, and the opportunities for runoff—and in a few places surface accumulation—of rainwater, are important in providing localized habitats for plants and animals. Large areas of loose, mobile sand provide the harshest and poorest of the major desert habitat types.

Desert soils are mainly immature, weakly developed in terms of their soil profiles, and mostly alkaline. Sands, sandy or gravelly loams, shallow stony soils, and alluvium (material deposited by rivers and streams) and scree-derived deposits (rocky material at the base of cliffs) predominate. Although almost always dry, these soils may support well-developed microbial communities, particularly in association with roots. Domestic animals, however, can have a deleterious impact by trampling and compacting the soil; this activity can reduce the infiltration of water and damage vegetation, leading to erosion and redistribution of soil materials.

Biota:

Flora

In most cases floristic links among desert regions are indicated by the presence of related species; it is unusual for identical species to be found in more than one region, except where they have been introduced by humans. (One notable exception is the prickly saltwort [Salsola kali], which occurs in deserts in Central Asia, North Africa, California, and Australia, as well as in many saline coastal areas.) Floristic similarities among desert regions are particularly obvious where no wide barriers of ocean or humid vegetation exist to restrict plant migration. Floristic links can be observed across the great expanse of desert from the Sahara to Central Asia, despite climatic contrasts between the hot environments in areas in and around North Africa and the much colder, though still dry, regions to the northeast. Floristic links are also pronounced from north to south in Africa and the Americas. As expected, the more isolated Australian desert flora has fewer similarities to the floras of other regions.

The daisy family is the most diverse plant family in deserts overall; it is especially numerous in Australia, southern Africa, the Middle East, and North America. However, except for the widespread Artemisia (wormwood) and Senecio, which are ubiquitous, different genera in this family are found in different desert regions. Although grasses predominate in the deserts of Iran, the Sahara, and the Thar Desert of India, members of the daisy family are almost as diverse here also. Another family well represented in deserts and other vegetation types is the bean family.

More locally significant plant families in deserts include the ice plant and lily families in Africa; the cabbage family from the Sahara to Iran; the carnation family in the Middle East; and the myrtle, protea, and casuarina families in Australia. All families also occur in other vegetation types in those same regions and represent elements of regionally prominent groups that have adapted to arid environments.

Members of some other plant families are common in desert vegetation but are not prominent components of other vegetation types. The best example is the chenopod or saltbush family, which is varied and diverse in arid and semiarid regions of Australia, North America, and from the Sahara to Iran, India, and Central Asia but scarce in other ecosystems. The cactus family is very prominent in deserts in the Americas but absent elsewhere. Another example is the smaller and generally less well-known family Frankeniaceae, which is typical of salty habitats and reaches its greatest diversity in deserts from North Africa to Central Asia and in western South America.

Trees and large shrubs are found in desert environments, although they are not often prominent, at least in the driest deserts and in many regions in which they have been virtually eliminated through human action. These desert species commonly belong to the bean family (such genera as Acacia and Cassia in most regions), with conifers being more locally distributed (such as Pinus in North America, Callitris in Australia, and Cupressus in North Africa and the Middle East). Tamarisks (Tamarix) are particularly important on sandy soils in Central Asia and also occur abundantly as introduced plants in parts of the North American and Australian deserts.

Smaller shrubs include Artemisia and Ephedra in Central Asia and North America, Atriplex in both these regions and also Australia, and Larrea in North and South America. Artemisia includes many species in deserts in the Northern Hemisphere, especially in temperate deserts where they dominate the vegetation across very large areas; this genus has not spread to any of the southern deserts.

Perennial grasses occur in most deserts. In the Northern Hemisphere, species of Aristida and Panicum are present in most hot deserts, and Stipa is found in temperate deserts. In Australia, spinifex grasses (Plectrachne and Triodia) are widespread.

A few large, common, conspicuous plants provide deserts with much of their regional character. In North America, the Sonoran Desert of northwestern Mexico and the adjacent areas of California and Arizona are dotted with large cacti, especially the tall saguaro (Cereus giganteus), while to the north in the cooler Mojave Desert the characteristic Joshua tree (Yucca brevifolia) is found. The creosote bush (Larrea tridentata) is common in both areas. The spiny, hummock-forming spinifex grasses typify Australian deserts, while fleshy, cactuslike species of Euphorbia are conspicuous in deserts located in parts of southern and eastern Africa.

Fauna

The larger animals of deserts are more regionally distinct than are the plants. Australia—geographically the most isolated continent—is most distinctive. The Australian desert fauna is marked by a very high diversity of reptiles, in comparison with other regions, and fewer mammals, a situation shared in some degree with the South American deserts. Many Australian mammals that are not rodents—the most diverse group of mammals in other deserts—are marsupials. Marsupials include a wide range of kangaroos, wallabies and their relatives, bandicoots, and the burrowing marsupial mole. Many smaller Australian desert mammals have recently become rare or extinct. A common animal in many Australian desert areas today is the European rabbit, which was introduced by humans. Various native species of rabbit and hare are typical occupants of most other desert regions. Camels have been introduced and are also well established in Australian deserts; this region is now the only place where camels occur in a totally undomesticated state.

In the hot deserts of the Old World, most large, herbivorous mammals at the present time, including camels, donkeys, goats, sheep, and horses, are domesticated. Wild species such as gazelles, ibexes, and oryxes are generally rare. Smaller burrowing rodents are more common and varied, as are reptiles. Large carnivores include foxes, hyenas, and several cat species, such as leopards and lynx, although the largest species, the lion, has become extinct there.

Many desert birds are nomadic, a habit that enables these creatures to relocate to areas in which rain has fallen recently and which provide a temporary abundance of food. Seed-eating finches and pigeons are among the typical birds of many desert regions; Australia is again the exception in having few finches but many desert parrots instead—for example, the budgerigar (Melopsittacus undulatus). Carnivorous birds can depend on their prey for water, but seedeaters need to drink and sometimes fly considerable distances to locate surface water.

Population and community development and structure

Desert plants and animals have many peculiar adaptations that enable them to survive long periods of moisture shortage and to take maximal advantage of short, infrequent wet periods.

Perennial plants commonly survive dry times by becoming physiologically inactive. In some cases they remain alive but are desiccated until water becomes available, at which time they rapidly absorb moisture through aboveground parts, swelling and resuming physiological activity. Some plants can absorb dew, which for many is the main water source. Mosses and lichens adopt this strategy, as do some flowering plants, which are sometimes called resurrection plants.

Other desert plants survive dry periods through underground organs such as bulbs, tubers, or rhizomes. These structures are inactive, requiring and using little water until triggered to grow by rain soaking into the soil. They then grow rapidly, using food reserves stored within, flowering and setting seed before soil moisture becomes substantially depleted once more.

Certain plants, including large woody plants and some herbaceous perennials, can remain physiologically active to some extent through dry periods. Plants employ several strategies to carry this off: water storage organs, such as the succulent stems of cacti, euphorbias, and ice plants, hold water until it is needed; very deep root systems reach soil moisture at depth; and certain features, such as leaves of reduced size or hairy or reflective leaves, reduce water loss.

Another typical feature of desert floras is their large proportion of ephemeral plants, which survive dry periods as resistant, dormant seeds. After a rain, the seeds germinate at once and the plants grow quickly, flower early, and complete their reproduction within a few weeks before the soil dries out again. It is primarily plants with this response that cause the deserts to bloom after infrequent storms.

Desert animals show many comparable adaptations to infrequent moisture availability in deserts, resulting in little activity during the usually dry times and intense activity in the brief, infrequent wet periods. During dry conditions many desert animals remain underground in holes or burrows in which the air is relatively cool and humid; more than half of desert animals are subterranean in their habits. Some, such as snails, may remain dormant for long periods, while others, such as burrowing mammals, emerge to feed only at night when conditions are cool and much less dehydrating. Reproduction may cease altogether in years of extreme drought, as it does in some lizards.

It is now clear that in several regions desert environments are expanding—a process called desertification. This process may be defined as land degradation in arid, semiarid, or dry, subhumid areas that results from various factors including climatic variation and human activities. In areas where the vegetation is already under stress from natural or anthropogenic factors, periods of drier than average weather may cause degradation of the vegetation. If the pressures are maintained, soil loss and irreversible change in the ecosystem may ensue, so that areas formerly under savanna or scrubland vegetation are reduced to desert.

There is some evidence that removal of vegetation can also affect climate, causing it to become drier. Bare ground reflects more incoming solar energy and does not heat up as much as ground containing vegetation. Thus, the air that is near the ground does not warm up as much and its vertical movement is reduced, as is atmospheric cooling necessary for condensation and ultimately precipitation to occur.

The main regions currently at risk of desertification are the Sahel region lying to the south of the Sahara, parts of eastern, southern, and northwestern Africa, and large areas of Australia, south-central Asia, and central North America. The arid regions with the longest history of agriculture—from North Africa to China—have generally less well-vegetated deserts. Plant-based desert classification systems from these regions contrast with those from places without such a long history of human usage, such as Australia and the Americas, probably because degradation of the vegetation has been occurring in the Old World regions for a much longer time. Systems incorporating desert vegetation types in Australia and the Americas recognize and include vegetation types with a prominent woody plant (shrub) component and tend to exclude some less arid but heavily altered vegetation types. The present extent of deserts in the Old World is thought to be significantly greater than it would be had human impact not occurred. Support for this view is found in various places, such as the several-thousand-year-old rock art from the central Sahara that illustrates cattle and wildlife in regions now unable to support these creatures.

Biological productivity

In the highly stressful desert environment, productivity is generally very low; however, it is also highly variable from time to time and from place to place.

Temporal variations are caused by the occasional input of moisture; this allows the vegetation to grow for only a short period before arid conditions resume. Spatial variations are due in part to the structural patchiness of the vegetation itself, as surface soil beneath shrubs is several times more fertile than it is between shrubs. Shrub roots contribute to this process by retrieving nutrients from the deep soil and depositing them in litter on the soil surface beneath the shrub canopy. Windblown litter that accumulates around shrubs and the microbial flora found in soil shaded by the shrub canopy also create patchy, fertile areas. Because human disturbance of desert vegetation commonly involves the partial or total removal of the shrub cover, the impact of human disturbance on these ecosystems is significant.

Additional Information

Deserts may seem lifeless, but in fact many species have evolved special ways to survive in the harsh environments.

Far from being barren wastelands, deserts are biologically rich habitats with a vast array of animals and plants that have adapted to the harsh conditions there. Some deserts are among the planet's last remaining areas of total wilderness. Yet more than one billion people, one-sixth of the Earth's population, actually live in desert regions.

What is a desert?

Deserts cover more than one-fifth of the Earth's land area, and they are found on every continent. A place that receives less than 10 inches (25 centimeters) of rain per year is considered a desert. Deserts are part of a wider class of regions called drylands. These areas exist under a “moisture deficit,” which means they can frequently lose more moisture through evaporation than they receive from annual precipitation.

Despite the common conceptions of deserts as hot, there are cold deserts as well. The largest hot desert in the world, northern Africa's Sahara, reaches temperatures of up to 122 degrees Fahrenheit (50 degrees Celsius) during the day. But some deserts are always cold, like the Gobi desert in Asia and the polar deserts of the Antarctic and Arctic, which are the world's largest. Others are mountainous. Only about 20 percent of deserts are covered by sand.

The driest deserts, such as Chile's Atacama Desert, have parts that receive less than .08 inches (2 mm) of precipitation a year. Such environments are so harsh and otherworldly that scientists have even studied them for clues about life on Mars. On the other hand, every few years, an unusually rainy period can produce "super blooms," where even the Atacama becomes blanketed in wildflowers.

Desert animals and plants

Desert animals have evolved ways to help them keep cool and use less water. Camels can go for weeks without water, and their nostrils and eyelashes can form a barrier against sand. Many desert animals, such as the fennec fox, are nocturnal, coming out to hunt only when the brutal sun has descended. Some animals, like the desert tortoise in the southwestern United States, spend much of their time underground. Most desert birds are nomadic, crisscrossing the skies in search of food. And among insects, the Namibian desert beetle can harvest fog from the air for water. Because of their very special adaptations, desert animals are extremely vulnerable to changes in their habitat.

Desert plants may have to go without fresh water for years at a time. Some plants have adapted to the arid climate by growing long roots that tap water from deep underground. Other plants, such as cacti, have special means of storing and conserving water.

Deserts, land use, and climate change

Some of the world's semi-arid regions are turning into desert at an alarming rate. This process, known as desertification, is not caused by drought, but usually arises from deforestation and the demands of human populations that settle on the semi-arid lands. The pounding of the soil by the hooves of livestock in ranching, for example, may degrade the soil and encourage erosion by wind and water. In northern China, growing urbanization, which left much of the land unprotected against wind erosion and the buildup of sediment from the surrounding desert, created a desertification problem, prompting the government to build a "great green wall" as a hedge against encroaching desert.

In existing deserts, some species are in peril because of climate change. Global warming threatens to change the ecology of deserts: Higher temperatures may produce more wildfires that alter desert landscapes by eliminating slow-growing trees and shrubs and replacing them with fast-growing grasses.

Many desert plants can live for hundreds of years. But in California, the iconic Joshua tree—the oldest found was 1,000 years old—may not survive a hotter climate, scientists warn. If they don't survive, that could affect species such as the yucca moth, which lays its eggs inside the Joshua tree flower.

Desert bird species could also be in danger from climate change, as heat waves lead to lethal dehydration.

Paradoxically, the effort to reduce planet-warming greenhouse gas emissions by expanding solar energy has also created some tensions for desert habitats. In the Mojave, the 2013 arrival of the Ivanpah solar thermal plant created concerns about how the facility would affect threatened desert tortoises, and conservationists are working to ensure solar energy projects like these can coexist with wildlife.

Other land use changes also threaten to degrade desert habitats. The downsizing of the Grand Staircase-Escalante National Monument poses a threat to some of the 660 bee species that live in the area, while the prospect of a border wall between the U.S. and Mexico could disconnect a third of 346 native wildlife species from 50 percent or more of their range that lies south of the border, including the desert bighorn sheep.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#2554 2025-08-06 17:35:16

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 51,261

Re: Miscellany

2354) Mongolia : The Most Sparsely Country In The World

Mongolia

Gist

Mongolia is located in Asia between Russia to the north and China to the south. Situated on mountains and plateaus, it is one of the world's highest countries with elevation averaging 5,180 feet (1,580 meters). Mongolia is 435 miles (700 kilometers) from the Yellow Sea.

Mongolia’s temperature can fluctuate as much as 35 degrees in one day. The country is very dry and receives only about four inches of rainfall per year. Southern Mongolia is dominated by the Gobi, which is one of the Earth’s coldest deserts and covers about 500,000 square miles (1,295,000 square kilometers).

Summary

Mongolia, historically Outer Mongolia, landlocked country located in north-central Asia. It is roughly oval in shape, measuring 1,486 miles (2,392 km) from west to east and, at its maximum, 782 miles (1,259 km) from north to south. Mongolia’s land area is roughly equivalent to that of the countries of western and central Europe, and it lies in a similar latitude range. The national capital, Ulaanbaatar (Mongolian: Ulan Bator), is in the north-central part of the country.

Landlocked Mongolia is located between Russia to the north and China to the south, deep within the interior of eastern Asia far from any ocean. The country has a marked continental climate, with long cold winters and short cool-to-hot summers. Its remarkable variety of scenery consists largely of upland steppes, semideserts, and deserts, although in the west and north forested high mountain ranges alternate with lake-dotted basins. Mongolia is largely a plateau, with an average elevation of about 5,180 feet (1,580 metres) above sea level. The highest peaks are in the Mongolian Altai Mountains (Mongol Altain Nuruu) in the southwest, a branch of the Altai Mountains system.

Quick Facts

Capital: Ulaanbaatar (Ulan Bator)
Population: (2025 est.) 3,569,000

Some three-fourths of Mongolia’s area consists of pasturelands, which support the immense herds of grazing livestock for which the country is known. The remaining area is about equally divided between forests and barren deserts, with only a tiny fraction of the land under crops. With a total population of fewer than three million, Mongolia has one of the lowest average population densities of any country in the world.

The Mongols have a long prehistory and a most remarkable history. The Huns, a people who lived in Central Asia from the 3rd to the 1st century bce, may have been their ancestors. A united Mongolian state of nomadic tribes was formed in the early 13th century ce by Genghis Khan, and his successors controlled a vast empire that included much of China, Russia, Central Asia, and the Middle East. The Mongol empire eventually collapsed and split up, and from 1691 northern Mongolia was colonized by Qing (Manchu) China. With the collapse of Qing rule in Mongolia in 1911/12, the Bogd Gegeen (or Javzandamba), Mongolia’s religious leader, was proclaimed Bogd Khan, or head of state. He declared Mongolia’s independence, but only autonomy under China’s suzerainty was achieved. From 1919, nationalist revolutionaries, with Soviet assistance, drove out Chinese troops attempting to reoccupy Mongolia, and in 1921 they expelled the invading White Russian cavalry. July 11, 1921, then became celebrated as the anniversary of the revolution. The Mongolian People’s Republic was proclaimed in November 1924, and the Mongolian capital, centred on the main monastery of the Bogd Gegeen, was renamed Ulaanbaatar (“Red Hero”).

From 1921 until the end of the 1980s, Mongolia was a one-party state closely tied to the Soviet Union. It received technical, economic, and military assistance from the Soviet Union and generally followed Soviet guidance in political and economic matters and in the building of a socialist society. However, beginning in 1990, forces for change in Mongolia ended the monopoly of political power by the communists in favour of free multiparty elections, coalition government, a new constitution, greater cultural and religious freedom with more emphasis on Mongol national traditions, a neutral position in international relations, and a transition to a market economy.

Details

Mongolia is a landlocked country in East Asia. It has a border with Russia to the north and the People's Republic of China to the south and southeast. Mongolia's political system is a parliamentary republic.

Mongolia is the biggest landlocked country that does not have a border with an inland sea. Most of the area in Mongolia are grassy steppes. The north and west parts of Mongolia have many mountains. Some of south Mongolia is the Gobi Desert.

There are 2,791,272 people in Mongolia. The country is the 18th biggest country in the world. It has an area of 1,564,116 sq km (603,909 sq mi). Mongolia has the lowest population density of all independent countries in the world. Mongolia has a large rural population. This means that most people do not live in cities. Many Mongolians are nomadic (people who always move from place to place and do not stay in one home). About 30% of the population are nomadic or semi-nomadic. There is also a big horse culture in Mongolia. In the past, most people in Mongolia were Buddhists (51.7%). 40.6% of Mongolians are nonreligious. The third most common religion in Mongolia is Islam. 3.2% of Mongolians are Islamic. Most of the Islamic people are ethnic Kazakhs. Most Mongolians are ethnic Mongols. Only 5% of the population are Kazakhs, Tuvans, and other ethnicities. Most of the ethnic minorities in Mongolia live in Western Mongolia. The largest city, and capital city is Ulaanbaatar. About half of the people in Mongolia live in Ulaanbaatar.

Mongolia is part of the United Nations, Asia Cooperation Dialogue, G77, Asian Infrastructure Investment Bank, Non-Aligned Movement and a NATO global partner. Mongolia joined the World Trade Organization in 1997.

History

The area which is Mongolia has been ruled by various nomadic empires. This was until the great 'Mongol Empire' was founded by Genghis Khan in 1206. After the Yuan Dynasty collapsed, the Mongols became nomads again. After the 16th century, Mongolia were influenced by Tibetan Buddhism. By the end of the 17th century, most of Mongolia was part of an area ruled by the Qing Dynasty. When the Qing Dynasty collapsed in 1911, Mongolia declared independence. But they had to fight against the Chinese. They were helped by the Soviet Union. In 1921, the world accepted its independence. Shortly after the death of Bogd Khaan, the last monarch of Mongolia the monarchy was replaced by a communist government in 1924, and the country was renamed the Mongolian People's Republic. Up until the fall of the Soviet Union, Mongolia was a satellite state for the Soviets. The Mongolian Red Cross Society was set up in 1939. It has its headquarters in Ulaanbaator. Following the break-up of the Soviet Union in 1991, Russia's interest in Mongolia has declined. China and South Korea are currently Mongolia's main trade and political partners.

Government

Mongolia is a parliamentary republic. The people vote for the people in their government. They vote for their President. The President of Mongolia is elected to a four-year term, and cannot be elected president more than twice. The current president is Ukhnaagiin Khürelsükh. He was first elected as president on June 25, 2021. They also vote for the members of their State Great Khural, which is their parliament. The president decides who the prime minister is.

The constitution of Mongolia gives Mongolian people many freedoms. They have the full freedom of expression and religion.

Mongolia has many political parties. The biggest parties are the Mongolian People's Party and the Democratic Party.

Foreign relations

Most of Mongolia's foreign relations are with Russia and China. Mongolia relies on these countries. 36% of imports are from China. 29% of imports are from Russia.

Mongolia has recently had relations with more countries. They have focused on foreign direct investment and trading.

Additional Information

Mongolia is a landlocked country in East Asia, bordered by Russia to the north and China to the south and southeast. It covers an area of 1,564,116 square kilometres (603,909 square miles), with a population of 3.5 million, making it the world's most sparsely populated sovereign state. Mongolia is the world's largest landlocked country that does not border an inland sea, and much of its area is covered by grassy steppe, with mountains to the north and west and the Gobi Desert to the south. Ulaanbaatar, the capital and largest city, is home to roughly half of the country's population.

The territory of modern-day Mongolia has been ruled by various nomadic empires, including the Xiongnu, the Xianbei, the Rouran, the First Turkic Khaganate, the Second Turkic Khaganate, the Uyghur Khaganate and others. In 1206, Genghis Khan founded the Mongol Empire, which became the largest contiguous land empire in history. His grandson Kublai Khan conquered China proper and established the Yuan dynasty. After the collapse of the Yuan, the Mongols retreated to Mongolia and resumed their earlier pattern of factional conflict, except during the era of Dayan Khan and Tumen Zasagt Khan.

In the 16th century, Tibetan Buddhism spread to Mongolia, being further led by the Manchu-founded Qing dynasty, which absorbed the country in the 17th century. By the early 20th century, almost one-third of the adult male population were Buddhist monks. After the collapse of the Qing dynasty in 1911, Mongolia declared independence, and achieved actual independence from the Republic of China in 1921. Shortly thereafter, the country became a satellite state of the Soviet Union. In 1924, the Mongolian People's Republic was founded as a socialist state. After the anti-communist revolutions of 1989, Mongolia conducted its own peaceful democratic revolution in early 1990. This led to a multi-party system, a new constitution of 1992, and transition to a market economy.

Approximately 30% of the population is nomadic or semi-nomadic; horse culture remains integral. Buddhism is the majority religion (51.7%), with the nonreligious being the second-largest group (40.6%). Islam is the third-largest religious identification (3.2%), concentrated among ethnic Kazakhs. The vast majority of citizens are ethnic Mongols, with roughly 5% of the population being Kazakhs, Tuvans, and other ethnic minorities, who are especially concentrated in the western regions. Mongolia is a member of the United Nations, Asia Cooperation Dialogue, G77, Asian Infrastructure Investment Bank, Non-Aligned Movement and a NATO global partner. Mongolia joined the World Trade Organization in 1997 and seeks to expand its participation in regional economic and trade groups.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#2555 Yesterday 17:56:04

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 51,261

Re: Miscellany

2355) Kazakhstan: The Largest Landlocked Country In The World

Gist

Kazakhstan is famous for its diverse landscapes, ranging from vast steppes to towering mountains and the Caspian Sea. It's also known for its rich nomadic history, unique cultural blend of tradition and modernity, and significant natural resources, including oil, gas, and minerals. Additionally, the Baikonur Cosmodrome and the modern architecture of cities like Almaty and Nur-Sultan contribute to its fame.

Summary

Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a small portion in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbekistan to the south, and Turkmenistan to the southwest, with a coastline along the Caspian Sea. Its capital is Astana, while the largest city and leading cultural and commercial hub is Almaty.

Kazakhstan is the world's ninth-largest country by land area and the largest landlocked country. Hilly plateaus and plains account for nearly half its vast territory, with lowlands composing another third; its southern and eastern frontiers are composed of low mountainous regions. Kazakhstan has a population of 20 million and one of the lowest population densities in the world, with fewer than 6 people per square kilometre (16 people/sq mi). Ethnic Kazakhs constitute a majority, while ethnic Russians form a significant minority. Officially secular, Kazakhstan is a Muslim-majority country with a sizeable Christian community.

Kazakhstan has been inhabited since the Paleolithic era. In antiquity, various nomadic Iranian peoples such as the Saka, Massagetae, and Scythians dominated the territory, with the Achaemenid Persian Empire expanding towards the south. Turkic nomads entered the region from the sixth century. In the 13th century, the area was subjugated by the Mongol Empire under Genghis Khan. Following the disintegration of the Golden Horde in the 15th century, the Kazakh Khanate was established over an area roughly corresponding with modern Kazakhstan. By the 18th century, the Kazakh Khanate had fragmented into three jüz (tribal divisions), which were gradually absorbed and conquered by the Russian Empire; by the mid-19th century, all of Kazakhstan was nominally under Russian rule. Following the 1917 Russian Revolution and subsequent Russian Civil War, it became an autonomous republic of the Russian SFSR within the Soviet Union. Its status was elevated to that of a union republic in 1936. The Soviet government settled Russians and other ethnicities in the republic, which resulted in ethnic Kazakhs being a minority during the Soviet era. Kazakhstan was the last constituent republic of the Soviet Union to declare independence in 1991 during its dissolution.

Kazakhstan dominates Central Asia both economically and politically, accounting for 60% of the region's GDP, primarily through its oil and gas industry; it also has vast mineral resources, ranking among the highest producers of iron and silver in the world. Kazakhstan also has the highest Human Development Index ranking in the region. It is a unitary constitutional republic; however, its government is authoritarian. Nevertheless, there have been incremental efforts at democratization and political reform since the resignation of Nursultan Nazarbayev in 2019, who had led the country since independence. Kazakhstan is a member state of the United Nations, World Trade Organization, Commonwealth of Independent States, Shanghai Cooperation Organisation, Eurasian Economic Union, Collective Security Treaty Organization, Organization for Security and Cooperation in Europe, Organization of Islamic Cooperation, Organization of Turkic States, and International Organization of Turkic Culture.

Details

Kazakhstan is a landlocked country in the middle of Eurasia. Its official name is the Republic of Kazakhstan. Kazakhstan is the ninth biggest country in the world, and it is also the biggest landlocked country in the world. Before the end of the Soviet Union, it was called "Kazakh Soviet Socialist Republic". The president of the country from 1991 through March 2019 was Nursultan Nazarbayev. Astana is the capital city of Kazakhstan. Almaty was the capital until 1998, when it moved to Astana.

The Kazakh language, which is a Turkic language, is the native language, but Russian has equal official status for all administrative and institutional purposes. Islam is the largest religion- about 70% of the population are Muslims, with Christianity practiced by 26%; Russia leases (rents) the land for the Baikonur Cosmodrome (site of Russian spacecraft launches) from Kazakhstan.

Geography

Kazakhstan is a transcontinental country mostly in Asia with a small western part across the Ural River in Europe. It has borders with the Russian Federation in the north and west, Turkmenistan, Uzbekistan and Tajikistan in the southwest, and China in the far east. The northern border is mostly with Siberia, Russia, so Russia has the longest border with Kazakhstan. Basically, Kazakhstan runs from the Caspian Sea in the west to the mainly Muslim Chinese autonomous region of Xinjiang. Kazakhstan has no ocean shoreline, but borders the Caspian Sea, which boats use to get to neighboring countries. The Caspian Sea is an Endorheic basin without connections to any ocean.

Natural resources

Kazakhstan has plenty of petroleum, natural gas, and mining. It attracted over $40 billion in foreign investment since 1993 and accounts for some 57% of the nation's industrial output. According to some estimates, Kazakhstan has the second largest uranium, chromium, lead, and zinc reserves, the third largest manganese reserves, the fifth largest copper reserves, and ranks in the top ten for coal, iron, and gold. It is also an exporter of diamonds. Kazakhstan has the 11th largest proven reserves of both petroleum and natural gas.

Regions

Kazakhstan is divided into 17 regions. They are divided into districts.

Almaty and Astana cities have the status of State importance and are not in any region. Baikonur city has a special status because it is leased to Russia for Baikonur cosmodrome until 2050.

Each province is headed by an Akim (provincial governor) appointed by the president. Municipal Akims are appointed by province Akims. The Government of Kazakhstan moved its capital from Almaty to Astana on December 10, 1997.

Additional Information

Kazakhstan, landlocked country of Central Asia. It is bounded on the northwest and north by Russia, on the east by China, and on the south by Kyrgyzstan, Uzbekistan, the Aral Sea, and Turkmenistan; the Caspian Sea bounds Kazakhstan to the southwest. Kazakhstan is the largest country in Central Asia and the ninth largest in the world. Between its most distant points, Kazakhstan measures about 1,820 miles (2,930 kilometres) east to west and 960 miles north to south. While Kazakhstan was not considered by authorities in the former Soviet Union to be a part of Central Asia, it does have physical and cultural geographic characteristics similar to those of the other Central Asian countries. The capital is Astana (formerly Nur-Sultan, Aqmola, and Tselinograd), in the north-central part of the country. Kazakhstan, formerly a constituent (union) republic of the U.S.S.R., declared independence on December 16, 1991.

Kazakhstan’s great mineral resources and arable lands have long aroused the envy of outsiders, and the resulting exploitation has generated environmental and political problems. The forced settlement of the nomadic Kazakhs in the Soviet period, combined with large-scale Slavic in-migration, strikingly altered the Kazakh way of life and led to considerable settlement and urbanization in Kazakhstan. The Kazakhs’ traditional customs uneasily coexist alongside incursions of the modern world.

Land:

Relief

Lowlands make up one-third of Kazakhstan’s huge expanse, hilly plateaus and plains account for nearly half, and low mountainous regions about one-fifth. Kazakhstan’s highest point, Mount Khan-Tengri (Han-t’eng-ko-li Peak) at 22,949 feet (6,995 metres), in the Tien Shan range on the border between Kazakhstan, Kyrgyzstan, and China, contrasts with the flat or rolling terrain of most of the republic. The western and southwestern parts of the republic are dominated by the low-lying Caspian Depression, which at its lowest point lies some 95 feet below sea level. South of the Caspian Depression are the Ustyurt Plateau and the Tupqaraghan (formerly Mangyshlak) Peninsula jutting into the Caspian Sea. Vast amounts of sand form the Greater Barsuki and Aral Karakum deserts near the Aral Sea, the broad Betpaqdala Desert of the interior, and the Muyunkum and Kyzylkum deserts in the south. Most of these desert regions support slight vegetative cover fed by subterranean groundwater.

Depressions filled by salt lakes whose water has largely evaporated dot the undulating uplands of central Kazakhstan. In the north the mountains reach about 5,000 feet, and there are similar high areas among the Ulutau Mountains in the west and the Chingiz-Tau Range in the east. In the east and southeast, massifs (enormous blocks of crystalline rock) are furrowed by valleys. The Altai mountain complex to the east sends three ridges into the republic, and, farther south, the Tarbagatay Range is an offshoot of the Naryn-Kolbin complex. Another range, the Dzungarian Alatau, penetrates the country to the south of the depression containing Lake Balkhash. The Tien Shan peaks rise along the southern frontier with Kyrgyzstan.

Drainage

Kazakhstan’s east and southeast possess extensive watercourses: most of the country’s 7,000 streams form part of the inland drainage systems of the Aral and Caspian seas and Lakes Balkhash and Tengiz. The major exceptions are the great Irtysh, Ishim (Esil), and Tobol rivers, which run northwest from the highlands in the southeast and, crossing Russia, ultimately drain into Arctic waters. In the west the major stream, the Ural (Kazakh: Zhayyq) River, flows into the Caspian Sea. In the south the waters of the once-mighty Syr Darya have, since the late 1970s, scarcely reached the Aral Sea at all.

The torrent of the Irtysh River pours some 988 billion cubic feet (28 billion cubic metres) of water annually into the vast West Siberian catchment area. In the late 1970s Soviet authorities developed extensive plans to tap the Irtysh River for use in irrigating the arid expanses of Kazakhstan and Uzbekistan, but the scheme was killed in 1986 because of the large investment required and concern for the project’s possible adverse ecological consequences. This left southern and western Kazakhstan, as before, greatly in need of additional water resources. Kazakhstan also suffers from the disastrous depletion and the contamination (by pesticides and chemical fertilizers) of the Syr Darya flow, on which the republic depends greatly for crop irrigation.

The Caspian Sea, the largest inland body of water in the world, forms Kazakhstan’s border for 1,450 miles of its coastline. Other large bodies of water, all in the eastern half of the country, include Lakes Balkhash, Zaysan, Alaköl, Tengiz, and Seletytengiz (Siletiteniz). Kazakhstan also wraps around the entire northern half of the shrinking Aral Sea, which underwent terrible decline during the second half of the 20th century: as freshwater inflow was diverted for agriculture, the salinity of the sea increased sharply, and the receding shores became the source of salty dust and polluted deposits that ruined the surrounding lands for animal, plant, or human use.

Climate

Kazakhstan’s climate is sharply continental, and hot summers alternate with equally extreme winters, especially in the plains and valleys. Temperatures fluctuate widely, with great variations between subregions. Average January temperatures in northern and central regions range from −2 to 3 °F (−19 to −16 °C); in the south, temperatures are milder, ranging from 23 to 29 °F (−5 to −1.4 °C). Average July temperatures in the north reach 68 °F (20 °C), but in the south they rise to 84 °F (29 °C). Temperature extremes of −49 °F (−45 °C) and 113 °F (45 °C) have been recorded. Light precipitation falls, ranging from 8 to 12 inches (200 to 300 millimetres) annually in the northern and central regions to 16 or 20 inches in the southern mountain valleys.

Soils

Very fertile soils characterize the lands from far northern Kazakhstan down to the more infertile, alkaline soils of the middle and southern areas. The vast stretches of arable land in the northern plains are the most intensely cultivated and productive. Other cultivated areas fringe the mountains in the south and east; irrigation and reclamation, when feasible, extend along river valleys into the deserts. Nuclear bomb testing conducted during the Soviet period near Semey (Semipalatinsk) contaminated the soils in the vicinity.

Plant and animal life

The vegetation on plains and deserts includes wormwood and tamarisk, with feather grass on drier plains. Kazakhstan has very little wooded area, amounting to only about 3 percent of the territory. Many animals, including antelope and elk, inhabit the plains. The wolf, bear, and snow leopard, as well as the commercially important ermine and sable, are found in the hills. Fishermen take sturgeon, herring, and roach from the Caspian Sea. In parts of northeastern and southwestern Kazakhstan, where commercial fishing collapsed as a result of industrial and agricultural pollution, efforts to revive fish populations have shown some success. In 2008 Kazakhstan’s Naurzum and Korgalzhyn state nature reserves were named a UNESCO World Heritage site; both are important habitats for migrating birds, as well as for many other animal species.

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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