What is the deepest rift zone in the world?

The largest rift zone in the world: Yarlung Zangbo Grand Canyon (the deepest is 6009 meters).

The largest rift valley in the world: the Great Rift Valley in East Africa

The Great Rift Valley in East Africa is the longest rift zone in the world and is known as the "scar of the earth". It is about 6500 kilometers long and 50-80 kilometers wide. At the bottom is a long and narrow lowland, sandwiched between the plateaus on both sides, like a huge dry valley, extending in the mountains.

The bottom of the Great Rift Valley in East Africa is 500-800 meters lower than the surface of the plateau on both sides on average, and the deep zones are about 3000 meters apart. Cliffs stand on both sides of the strait, and volcanoes stand tall on the plateau; The lake at the bottom of the rift valley makes the lakes and mountains in East Africa more magnificent. The Rift Valley in East Africa is divided into two zones: in the east, it starts from Zambezi River, passes through Lake Malawi, Lake Ethiopia and Lake Turkana, passes through the small lake in Ethiopia, reaches Lake Asare, Red Sea and Gulf of Aqaba, and extends to the Dead Sea and Sea of Galilee; The west gradually disappears from Lake Tanganyika and Lake Kivu to the north of Lake Mobutu.

The natural belt of the Great Rift Valley in East Africa has a magnificent landscape. Many lakes, large and small, are like a string of pearls on the ground. Most of them have one thing in common: the banks are steep and deep, and their shapes are long and narrow.

Lake Tanganyika is the longest lake in the world, about 670 kilometers long, with steep cliffs, rippling blue waves and beautiful scenery. It is the second deepest lake in the world, and its bottom is 662 meters lower than the sea level. Lake Malawi is about 580 kilometers long and its deepest point is 234 meters below sea level. The banks of the Red Sea are also steep, and the sea is deep, reaching the deepest point of 3050 meters. The Gulf of Aqaba is about 1828 meters deep. The deepest part of the Sea of Galilee is 209 meters below sea level.

There are many active and extinct volcanoes near the rift zone, and Mount Kilimanjaro and Mount Meru are world-famous. This is still an unstable area. Nyiragongo volcano is 3470 meters above sea level. At the top of the volcano, there is a crater 300 meters long and 100 meters wide, and there is the only fiery magma lake in the world. Red magma, boiling and rolling, makes a roar, like molten iron rushing, which is another magnificent spectacle of nature. The top of the mountain is covered with dense volcanic smoke all the year round, and there is a pungent smell of sulfur everywhere.

1979, near Lake Asare, a group of volcanoes erupted simultaneously, which increased the distance between Africa and Arabian Peninsula by120cm. This phenomenon has never been observed before.

Scientists believe that the rift zone in East Africa is formed by large faults, and the crustal fracture is caused by thermal convection in the upper mantle. The upwelling of mantle makes East Africa uplift into a plateau, and spreads to both sides with the upwelling, which also makes the crust in a state of tension and produces cracks. First, there are two parallel cracks in the earth's crust. Then, the ground in the middle of the fault gradually sinks, while the two wings of the fault rise relatively, forming two walls of the rift valley and a deep broadband lowland. At the same time, it is accompanied by volcanic and seismic activities. Those low-lying places have accumulated water into lakes.

Scientists believe that today, along the Great Rift Valley in East Africa, a great crustal change is going on. This rift valley is a subsidence zone. The two major plates of the earth's crust, namely the Arabian plate and the African plate, have separated and expanded at a rate of about 2 cm per year, separated by a young Red Sea.

The Rift Valley in East Africa is also expanding, about 1 cm per year. The flight survey of the Great Rift Valley in East Africa also confirmed that a crustal change process is slowly going on here.

According to the theory of mantle heat flow, scientists believe that the Great Rift Valley in East Africa will separate the African continent under this tension. Millions of years later, it may become a bigger fault zone, and a new ocean will separate Kenya, Tanzania and other countries in East Africa from the rest of Africa, making it an East African island much larger than Madagascar.

According to the observation data, American scientists even drew a map of the world's land and sea distribution after 8 million years: Panama will disappear in the waves, Florida Peninsula will be connected with the West Indies and South America, and Greenland will be far away. The Caspian Sea has been filled, the Persian Gulf has become a plateau, and the Great Rift Valley in East Africa has become a new ocean. Caihuaqun Island, Australia and New Zealand are integrated into a new majestic mountain range. Contrary to the karst stone forest, some giant rock forests are not formed by water erosion, but by geological structure, volcanic activity, weathering and sea erosion. Wave Rock in Australia, Ayers Rock and Devil Rock in the United States are all world-famous strange rocks and tourist attractions.

Boyan is located on the great plateau of Western Australia. The altitude of the whole plateau is 180 ~ 600 meters. It consists of Pingdingshan, isolated mountains, wind-eroded cliffs and mountains, as well as flat sand plains, undulating sand ridges and many dry lakes.

Wave rock is like a huge barrier, and the steep rock wall is covered with vertical wavy stripes. People stood in front of the rock wall and looked at it. Waves and rocks are like surging waves and rushing waterfalls, which come head-on and are magnificent. It got its name.

Scientists believe that the basement of the mainland is ancient granite geology, with a history of 1 100 million years, which is larger than the area of France. The climate here is dry and plants are scarce. Under the erosion of wind and sand, after a long time, this strange wind erosion cliff and wave rock have been formed.

In El Lu Lu badminton National Park, about 500 kilometers away from Ayers Hot Springs, there is a huge rock-Ayers Rock lying quietly. It stands out on the desert plain, with a height of 348 meters, a circumference of 9 kilometers at the bottom and an area of about 1.200 hectares. It is the largest monolithic rock in the world.

Ayers Rock has a steep wall, very steep. It usually takes 1.5 hours to climb Ayers Valley from the foot of the rock. As long as you climb to the rock wall above 10 meter, you will see a wonderful picture suddenly unfolding on the flat wasteland: Olgas, 32 kilometers west, lies on the horizon, flashing purple light; More than 30 dome-shaped peaks stand irregularly, forming a charming realm.

The color of Ayers Rock changes with the weather. At dawn, under the sunlight, it appears bright pink or vermilion; In the evening, under the setting sun, it is orange red. During the day, it appears brown, yellow or purple with the change of time and cloud cover.

In the evening and rainy days, Ayers Rock will present a strange landscape. The setting sun falls on the horizon, and the soft light shines on various objects, forming long shadows. Only Ayers Rock still stands brightly, like an island full of light. When the sun fell below the horizon, it turned into a fiery red dome, burning violently. This is the iron oxide particle in the rock, which is red after being illuminated. Soon, the shadow came quickly and shattered the "flame". When the moon rises, Ayers Rock loomed a vague outline from the darkness.

Ayers Rock is vibrant and ancient. Geologists believe that 450 million years ago, the original sandstone of Ayers Rock was in a vertical state because of the uplift and overlap of the blocks. Later, after tens of millions of years of wind and rain, the surrounding sandstone weathered and disintegrated, and only it still stood. This may be because the giant rocks are under pressure from different directions, and the natural joints between rocks and weathered rocks are tightly squeezed, thus preventing water seepage and slowing down weathering, and Ayers Rock has thus left the reputation of "the stone of ten thousand generations".

There is a steep butte in Wyoming, USA. It rises like a boulder, like a stump, and stands like a huge stone pillar in the sky. People call it the "Devil Tower".

The Devil's Tower consists of a cluster of long and straight stone pillars, much like a pile of organ pipes. The bottom of the tower is about 300 meters in diameter, while the top of the tower is only 80-90 meters in diameter. The tower is 265 meters high (with an inclination of 80) and is composed of ochre yellow igneous rocks. But its color is constantly changing with time, wind and rain, and different observation directions. On rainy days, the top of the tower is hidden in thick clouds, and the soaring momentum, coupled with gray and black, gives people a gloomy and terrible feeling.

After the surface of the Devil's Tower was weathered, lichens grew in some places and turned green, yellow-green or brown. The US Congress once selected it as the first "national scenic spot" in the United States, and Americans called it "one of the most amazing peaks on earth". Not long ago, a science fiction film shot in Hollywood used the Devil's Tower as a place where "aliens" landed their spacecraft on the earth.

How did the Devil's Tower come into being? It turns out that this area was once submerged by seawater, and the seabed sediments formed shale, sandstone, gypsum and limestone layers. Later, about 50 million years ago, underground magma seeped out of the ground along the cracks and immersed in sedimentary rocks. Lava completely surrounds the ancient rocks and slowly cools and crystallizes, forming vertically staggered cracks and textures. Later, igneous rocks buried under sedimentary rocks were gradually exposed. After millions of years of wind and rain erosion, those fragile rocks covered outside completely disappeared. After the igneous rock was exposed, the shape of the tower also changed due to erosion. After water seeps into the cracks in the rock, it freezes and expands, causing the stone pillars to crack and collapse. The debris left after the collapse of the stone pillar formed a stone curtain skirt around the bottom of the tower.