Where is the largest canyon in the world?

Also known as the East African Rift Valley or the Afro-Arabian Rift Valley.

[Edit this paragraph] Introduction to Rift Valley

The Rift Valley in East Africa is the largest fault zone on the world continent, which looks like a huge scar from satellite photos. When flying over the vast Indian Ocean and entering the equatorial sky of the East African continent, looking down from the window, a huge "knife mark" appeared on the ground, which suddenly made people feel amazing and magical. This is the famous "East African Rift Valley", also known as "East African Grand Canyon" or "East African Earth Trench".

Because this rift valley has actually gone beyond the scope of East Africa and extended to the Dead Sea, some people call it the "Africa-Arabia Rift Valley System".

Part of the largest rift valley on the earth's surface. It extends south from Jordan, across Africa and ends in Mozambique. The total length is 6400 kilometers (4000 miles) and the average width is 48-64 kilometers (30-40 miles). There are the Jordan River, the Dead Sea and the Gulf of Aqaba in the north. It flows southward along the Red Sea into the Danajir depression in Ethiopia, followed by Lake Rudolph (now called Lake Turkana), Lake Naivasha and Lake Magadi in Kenya. A section of the eastern edge of Tanzania is not obvious because of erosion. After the Rift Valley in East Africa, it reached the Indian Ocean coast of Mozambique through the Shire Valley. The bifurcated rift in the west extends in an arc from the northern end of Nyasha Lake, passing through Lake Lukwa, Lake Tanganyika (the second deepest lake in the world), Lake Kivu, Lake Edward and Lake Albert. Rift lake is deep, like a fjord. The plateau near the rift valley generally inclines upward toward the rift valley, and some lakes are far below the sea level. The average drop to the bottom of the valley is 600-900 meters (2,000-3,000 feet), and some areas exceed 2,700 meters (9,000 feet). It is speculated that the rift valley was formed in Pliocene and Pleistocene, and some areas were accompanied by large-scale volcanic activity at the same time, thus forming peaks such as Mount Kilimanjaro (5895 m [19340 ft]) and Mount Kenya (5 199 m [17058 ft]).

This great rift valley, which is equivalent to 65438+ 0/6 of the earth's circumference, is magnificent. It is the largest rift zone in the world. Some people vividly call it "a big scar on the earth's epidermis", which has fascinated many people throughout the ages.

[Edit this paragraph] Rift branch

This rift zone is located in the east of Africa, starting from the mouth of Zambezi River in the south, passing through Shire Valley to the north of Lake Malawi (Nyasa Lake), and then splitting into two branches:

East branch rift zone: it is the main rift, along the east side of Lake Victoria, passing through Tanzania and central Kenya to the north, crossing the Ethiopian Plateau into the Red Sea, and then extending from the Red Sea to the Jordan Valley to the northwest, with a total length of nearly 6,000 kilometers. The rift valley here is about tens to 200 kilometers wide, and the bottom of the valley is mostly flat. There are steep cliffs on both sides of the rift valley, and the height difference between the bottom and the top of the cliff ranges from several hundred meters to 2000 meters.

West branch rift zone: generally along the west side of Lake Victoria, it passes through a series of lakes such as Lake Tanganyika and Lake Kivu from south to north, and gradually disappears to the north, with a relatively small scale, with a total length of 1700 km. There are many volcanoes on the plateau on both sides of the Rift Valley in East Africa, such as Mount Kilimanjaro, Mount Kenya and Nyiragongo, and there are about 30 beaded lakes at the bottom. These lakes are long and narrow and deep. Among them, Lake Tanganyika is 670km long from north to south and 40km to 80km wide from east to west, making it the longest lake in the world, with an average water depth of 1 130m, making it the second deepest lake in the world after Lake Baikal in North Asia.

[Edit this paragraph] Formation reason

More than 654.38 million years ago, the fracture of the earth's crust formed this huge subsidence zone. According to the theory of plate tectonics, this is the place where the land masses are separated, that is, eastern Africa is just in the zone where mantle materials rise and flow strongly. Under the action of upwelling, the crust of East Africa rises to form a plateau, and upwelling in opposite directions on both sides is dispersed, which makes the fragile part of the crust crack and sag, becoming a rift zone. The average speed of tensile fracture is 2 cm ~ 4 cm per year, which is still going on, and the rift zone is still expanding to both sides. Because this is an active area of crustal movement, there are many volcanoes and earthquakes.

The Great Rift Valley in East Africa is a geographical wonder that runs through East Africa, the largest rift zone in the world, and is known as the scar of the earth. It is said that due to the crustal plate movement about 30 million years ago, the strata in eastern Africa broke. Geologists predict that the African continent will break into two continental plates along the rift valley in the future.

[Edit this paragraph] The origin of mankind

How did the Great Rift Valley form? According to the investigation of geologists, about 30 million years ago, due to the strong crustal fracture movement, the mainland drifted away from the Arabian ancient land mass, forming a rift. At that time, the crust in this area was in a period of great movement, and the whole area was uplifting, and the mantle material under the crust rose and bifurcated, resulting in great tension. It is under this tension that the crust breaks and a rift is formed. Due to the continuous uplift movement, the crustal fracture is constantly produced, and the underground lava is constantly pouring out, gradually forming a tall lava plateau. Volcanoes on the plateau have become numerous peaks, and the subsidence area of faults has become the bottom of the Great Rift Valley in East Africa.

According to the analysis of geophysical exploration data, it is concluded that there are many active volcanoes in the Great Rift Valley in East Africa, and the uplift phenomenon is still spreading to the two wings. Although the speed is very slow, with an average annual expansion rate of only 2 to 4 centimeters in the past 2 million years, if it continues to develop, one day in the future, the East African Rift Valley will eventually separate its eastern land from the African continent, thus creating new oceans and numerous islands.

The Rift Valley in East Africa is also one of the earliest cradles of human civilization. In the late 1950s, a prehistoric skull fossil was found in Oduwe Valley in northern Tanzania, west of the east branch of the East African Rift Valley. According to the determination and analysis, this skull fossil was named "East African Warrior" 2 million years ago. 1972, a 2.9 million-year-old skull was excavated on the shore of Lake Turkana in the northern part of the rift valley. Its sacrifice is very similar to that of modern people, and it is considered as a typical "capable person" who has completed the transformation from apes to humans. 1975, the remains of "homo habilis" dating from 3.5 million years ago were found in the rift valley at the junction of Tanzania and Kenya, and the footprints of "homo habilis" 22 meters long were found in the hardened volcanic ash layer. This shows that as early as 3.5 million years ago, there were people who could walk upright in the Rift Valley, belonging to the earliest members of mankind.

This series of archaeological discoveries in the Great Rift Valley in East Africa proves that Africa, once described by western colonists as "barbaric, poor and backward", is actually one of the cradles of human civilization and a land with splendid ancient civilization.

[Edit this paragraph] Landscape

Rift lake

At the bottom of the rift valley is an open Yuan Ye, and more than 20 long and narrow lakes are scattered in the valley like a string of glittering sapphires. Lake Navasha and Lake Nakuru in the middle are habitats for birds and other animals, and are also important tourist areas and wildlife reserves in Kenya. Lake Navasha is the highest lake in the rift valley, with an altitude of 1.900 meters. Lake Magadi in the south produces trona, which is an important mineral resource in Kenya. Lake Turkana in the north is one of the birthplaces of human beings, where ancient human skull fossils of 2.6 million years ago were found.

The Great Rift Valley in East Africa is also a huge natural livestock pond, where most lakes in Africa are concentrated, with about 30 large and small, such as Abbe Lake, Sarah Lake, Turkana Lake, Magadi Lake, Victoria Lake (located on the plateau between the East and West Rift Zones) and Jiaojia Lake. The former is the largest lake in Africa, and the lake is very shallow. Lake Malawi (7 times the maximum width and 706 meters deep, making it the fourth deepest lake in the world) and Lake Tanganyika (0.3 times the maximum width and 0.470 meters deep, making it the second deepest lake in the world). These lakes spread out in long strips and beaded along the palaces of the rift valley, becoming a great beauty on the East African plateau.

The lakes in these rift zones are blue, vast and ever-changing. They are not only tourist attractions, but also rich in water resources, with fertile land, lush vegetation and numerous wild animals. Elephants, hippos, African lions, rhinos, antelopes, foxes, flamingos and vultures all live here. The governments of Tanzania, Kenya and other countries have turned these places into wildlife parks or nature reserves. For example, Lake Nakuru, located in the suburb of Nakuru, the capital of Kenya's Canyon Province, is a lake rich in bird resources, with more than 400 species of birds, which is a key national park in Kenya. Among many birds, there is a bird named Fleming, which is called the most beautiful bird in the world. Under normal circumstances, there are more than 50,000 flamingos in the lake area, reaching 1.5 million at most. When thousands of birds fly or perch on the lake, from a distance, there is a rosy glow, which is very beautiful.

Before seeing the Great Rift Valley in East Africa, many people imagined that it must be a long, narrow, dark, gloomy and horrible fault flow, with long weeds and rugged rocks inside, and no one set foot in it. In fact, when you come to the Rift Valley, you will see a completely different scene: in the distance, the dense virgin forest covers the peaks of Gong Mian, and the hillside is covered with Xianbinbin and cactus with purple and yellowish flowers. Nearby, the grassland is vast, green bushes are scattered among them, weeds are green, flowers are blooming, and several lakes in the depths of the grassland are sparkling and floating among mountains and rivers. The bottom of the rift valley is flat and magnanimous, with abundant grass and lush forests, full of vitality.

Lake area of the Rift Valley in East Africa

The Rift Valley in East Africa is the main agricultural area in Kenya because of its abundant rainfall and fertile land. In the Rift Valley Lake area of East Africa, rivers flow into the lake from the surrounding highlands, with abundant rainfall and dense river network, Marombe Lake in southern Malawi. It is only 19 km north of the south entrance of Lake Malawi. It is 29 kilometers long, 0/4.5 kilometers wide and covers an area of 420 square kilometers. Water depth 10- 13m. Located in the southern section of the Great Rift Valley in East Africa, the Schiller River runs through it. Originally part of Lake Malawi, it was separated by falling water. Aquatic products are abundant and fisheries are developed. The theory of African origin, which is beneficial to navigation, is the mainstream theory at present. Scientists have found a large number of early hominid fossils in the Great Rift Valley in East Africa, especially the skeletal fossils of "Lucy", showing the morphological and structural characteristics of both humans and apes. The Rift Valley in East Africa is also the region with the most frequent and intense earthquakes in Africa.

In Kenya, the outline of the rift valley is very clear. It runs through the north and south, bisecting the country, and crosses the whole country right across the equator. Therefore, Kenya got a very interesting title: "East African Cross". On both sides of the rift valley, there are cliffs and broken walls, and the mountains are undulating, just like two towering walls. Nairobi, the capital, is located on the eastern "wall" at the southern tip of the Great Rift Valley in East Africa. Climbing the cliff and looking around, I saw the pine and cypress at the bottom of the rift valley deep and unfathomable. An extinct volcano is like a projectile thrown into a canyon, and a lake is like a sparkling gem. Mount Kenya on the side of the Rift Valley in East Africa is 5 199 meters above sea level, which is the second highest peak in Africa.

Great plains of east Africa

This area is the Great Plains of East Africa and the highest landlord in Africa, with mild and cool climate, abundant rainfall, beautiful scenery and rich products, rich in tea, coffee, fruits, pyrethrum and sesame. Here, coffee beans can be picked twice a year, tea can be picked once a year for more than nine months and a half, pyrethrum can be picked once a year from 18 to 14 days, and Ma Yu can be picked every day after maturity.

[Edit this paragraph] Future forecast

Title:/kloc-The eighth continent will appear on the earth in 0/0 million years.

Original text:

In September, 2005, the ground in a place in northern Ethiopia suddenly sank 10 feet, and quickly split to both sides. The big hole was enough to swallow several camels and goats. In the next three weeks, there were 160 earthquakes in this place, forming a large crack with a width of 25 feet and a length of about 0.34 miles.

Tim Wright, a geophysicist at the University of Leeds in the United Kingdom, used satellite radar data to accurately piece together the formation process of this crack. When African and Arabian tectonic plates drift to both sides, the crust between the two plates will weaken. Wright said: "The magma formed at the bottom of the earth's crust will fall periodically, just like a lava lamp, forming a hollow balloon, which will gradually expand. When this' balloon' reaches the critical pressure, it will explode. "

According to Wright's estimation, in the next 654.38+billion years, the crack will continue to expand, when the Horn of Africa will be completely separated from the African continent, forming the eighth continent on earth-East Africa. Wright said that this kind of geological process always happens, but ground cracking usually only happens at the bottom of the sea, which is difficult for people to see. He said: "This is the first time that we have directly observed this extremely important geological process with modern instruments."

This discovery caused a sensation in the scientific community. In 2006, investigation teams from Britain, France, Italy and the United States came from afar. After analysis and research, they predicted that a new continent would be formed after 1 10,000 years, the Great Rift Valley in East Africa would be 10 times longer than it is now, and the Cape of Good Hope in East Africa would be separated from the African continent. In this regard, American geologist Cindy Ebinger said: "Many people think that violent geological phenomena only occurred in distant ancient times, but now we can see that they are happening."

[Edit this paragraph] China Scientific Research

Reasons for scientific research

At the invitation of Addis Ababa University in Ethiopia, a scientific investigation team composed of scientists from the Institute of Geology and Earth, the Institute of Geography and Resources, and the Institute of vertebrate paleontology and Paleoanthropology of China Academy of Sciences left for Ethiopia and Kenya on February 8, 2007 for a 20-day scientific investigation of the Great Rift Valley in East Africa. The main purpose of this scientific investigation activity includes exploring the complex physical and chemical changes, geological structures and geological processes of the formation and evolution of the Great Rift Valley in East Africa; Tectonic theory of the formation of ground depression; The possible impact of future changes in the Great Rift Valley in East Africa on human beings, such as the impact of natural disasters such as volcanic eruptions, mudslides and floods on global climate change; The influence of the change of the rift valley ecological environment on the world; The origin of mankind and further discussion on cooperation with Africa.

Scientific investigation route

-Arrived in Addis Ababa, Ethiopia on August 2nd.

-Drive to Chencha Mountain at an altitude of 2,500 meters on August 3 to visit the Duoze people, their traditional weaving culture and houses built with bamboo. From here, we can observe all kinds of plants and mountain ecology in the mountains on both sides of the Great Rift Valley.

-Arrive at Nico Wild Park on the morning of August 4th, and observe zebra, Wayne antelope, gazelle and many lowland birds at close range. Take a boat to Chamo Lake in the afternoon, where there are 6 meters of wild crocodiles, hippos and pelicans, which is a good place to observe and study the wild animals in the lake area.

-On August 5th, we visited the Awasa area, where we can see the whole picture of Lake Awasa and the ecology of the Great Rift Valley in East Africa at a glance.

—— Entering the tropical rain forest area on August 6th, mainly investigating the ecological structure of the tropical rain forest.

-On August 7th, we continued to inspect the birds and plants in the no man's land of the rainforest.

-On August 8th, I entered Mount Bari National Park to study Ethiopian endemic plants, birds and various mammals, especially the wild baboons not found in China. Understand the culture of the indigenous Oromo people.

-On August 9th, climb Mount Toulu and Harenah Forest, the third highest mountain in Ethiopia, and start the most difficult journey.

-August 10, crossing Sofoma Cave and Weibi River to investigate the geological changes at the bottom of rift valley.

-On August 1 1, I bypassed Lake Langano and went to O 'Hara Wild Park to visit ostrich farms, gazelles, warthogs, flamingos, pelicans and other birds.

——/kloc-In August of 0/2, we crossed the Rift Valley and arrived in Nazaris to observe volcanic activity.

-On August 13, we drove to Afa, which is farther away and has more frequent volcanic activities, to investigate the volcanic eruption.

-August 14 Visit the local nomadic people in Avash to learn about African tribal culture.

—— August 15 Exchange scientific research results with Ethiopian scientists at Addis Ababa University.

Abstracts of scientific research contents

"The project I brought this time is the study of tree rings in the Great Rift Valley in East Africa." Dr. Liu Xiaohong, Institute of Environment and Engineering in Cold and Arid Regions, Chinese Academy of Sciences, carefully explained his topic to reporters: "The growth process of trees is easily influenced by climatic factors such as precipitation, temperature and humidity, which are like' climate codes' and are quietly written in the tree rings. By studying all kinds of information in tree rings, we can restore the climate situation hundreds or thousands of years ago. The Rift Valley in East Africa is the only region on the earth where the original tree species are well preserved. This scientific research activity should be able to obtain important tree ring information. "

Liu Xiaohong said that there are four main methods to study paleoclimate in the world, besides tree rings, there are loess, lakes and ice cores. The common principle of these methods is that natural climate changes acted on the living things in trees, loess, lakes and glaciers at that time, and the climate of different times formed different accumulation layers, one covering the other, and all the results were well preserved.

"The more important role of paleoclimate research is to find reasons for global warming. Through the study of tree rings and ice cores, we want to know how much carbon dioxide was on the earth thousands and tens of thousands of years ago, and then compare it with the current carbon dioxide content, thus proving the' role' that carbon dioxide plays in global warming. In order to get the ice core, China scientists went to the South Pole many times. This time, they went to the Great Rift Valley in East Africa for scientific research, and they just got more primitive and complete tree ring information, which is a rare opportunity. "

Although he will leave in a few days, Liu Xiaohong can't wait.

[Edit this paragraph] Related books

Title: The Most Beautiful Scar on the Earth's Surface —— Revealing the Great Rift Valley in East Africa (the first scientific investigation in the Great Rift Valley published books)

Publishing House: Huacheng Publishing House, published in June 5438+ 10.

Text: The book has more than 50,000 words.

Pictures: hundreds of wonderful pictures.

Format: 16 folio full-color page

Price: 49 yuan.

brief Introduction of the content

The author of this book followed the China Scientific Investigation Association to experience the Rift Valley in East Africa, and created this book by introducing the local history, culture, natural environment and human landscape in East Africa (mainly Ethiopia). The book describes the earliest and most complete ancient human remains, nicknamed "Lucy"; Interesting customs and habits in East Africa and various unique endangered and precious animals; The eight scenic spots that have been included in the world cultural heritage are very informative and interesting. The pictures in the book are all the latest first-hand materials, all of which were taken by the author himself. This book is also prefaced by Mr. Huang Wanbo, a famous paleoanthropologist of Chinese Academy of Sciences, which adds a certain academic nature on the basis of readability.

Editor's recommendation

This book brings together exploration, tourism and archaeology in East Africa. It is not only a rare guide to cultural tourism, but also an interesting textbook of ancient human beings, wildlife and African history in Xian Yi. Opening this book is like visiting the Rift Valley in East Africa.

Africa is the birthplace of mankind, where the earliest and most complete ancient human remains-"Lucy" have been excavated.

There are rare and endangered wild animals, strange and interesting customs and habits, and eight scenic spots listed in the world cultural and natural heritage. You can walk into Ethiopia, the second oldest Christian country in the world, and visit the legendary Ark of God. You can enjoy 13 months of sunshine in Huacheng without a house number.

Brief introduction of the author

Deng Bo: Born in 1972. Leizhou people.

Yangcheng Evening News reporter. Famous documentary photographer. Photographs pay equal attention to humanities and images, and are full of emotion and impact.

One Woman and 600 Children won the second prize of the 10th China Prize for Journalism.

Gan Tang Village Endless Poisonous Water Rolling won the second prize of the 11th China News Award.

12 won the China Prize for Journalism; Re-evaluation of the Gold, Silver and Bronze Awards in China Annual Photojournalism Competition.

15 won the first, second and third prizes of Guangdong News Award.

The Asian regional photography competition won the highest award-the best photographer award.

The first and third sessions won the silver prize of China International Photojournalism Competition (referred to as "Huasai").

The Communist Party of China (CPC) Propaganda Department won the highest prize for hosting a large-scale environmental protection photo exhibition.

Second prize of the third annual United Nations International Folk Photography "Human Contribution Award".

More than a dozen works won the China Evening News News Award, and also won many awards in various photography competitions and news selection held by the state, provinces and cities.

Library catalogue

foreword

Huang Wanbo, the cradle of the rise of mankind

"Comparing vertically and horizontally, there is only one center of human origin on the vast land, and that is Africa."

The African continent on the map looks like the fossil skull of an Australopithecus. The Great Rift Valley spans almost all countries in East Africa, and the longest is in Ethiopia. Afa basin records too many honors and dreams of paleoanthropology.

chapter one

Long live 3.2 million mothers

-Pursuing our common ancestor

Discover the legendary experience of "Lucy". The oldest human skeleton fossil named after The Beatles's famous music confirms the revelry of the discoverer in the 1970s-

"In a sense, I think we found our mother."

chapter two

Visit the Rift Valley in East Africa

The African Rift Valley is not an abyss. Its widest part is more than 200 kilometers, with plains and mountains. All kinds of wonders are at the bottom, with the footprints of "Lucy", which is a paradise for bats, monkeys, lions, baboons, warthogs and flamingos. There are also critically endangered species: wolves, African wild donkeys and black rhinoceros. ...

chapter three

History and heritage

Ethiopia is the second oldest Christian country in the world. It is said that the ark of the Ten Commandments of God is hidden in a mysterious church here. The eight world cultural and natural heritages attest to the brilliant and unimaginable changes of fate experienced by this country. The eighth wonder of the world, the stone-chiseled Libera Cathedral, has been buried for 700 years, but it is still amazing.

chapter four

Beautiful black

"Ethiopia" means "suntanned face". They are beautiful. In this male land, tenderness and wildness are rare. "they still live there ... this is both worrying and a miracle." The writer Paul Telu described the current situation in Africa like this.

chapter five

Wilderness and land

The land in the rift valley breeds ten different ecosystems, such as cactus, shrub, grassland and woodland ... It has a mild climate and rich products, such as tea, fruit and coffee. About one third of the people in the world drink coffee, but few people know that coffee originated in Ethiopia, and the coffee tree is their national tree.

Chapter vi

The capital Addis Ababa

When you come here, you can enjoy 13 months of sunshine a year, including only 5 days in one month. The tallest city in Africa means "flowers". The only capital in the world without a house number is the post office, and there is no postman. Will you get lost in it?