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Global plate
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Global plate
catalogue
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* 1 concept
* 2 Historical evolution of plate tectonic theory
* 3 Plate distribution
* 4 Plate boundary
* 5 board movement
* 6 See.
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concept
Plate is a concept put forward by plate tectonics. According to the plate tectonic theory, the lithosphere is not a whole, but divided into many blocks, which are called plates. There are other small dishes in the plate.
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Historical evolution of plate tectonic theory
Croatian seismologist Mohorovicic discovered the crust-mantle boundary between the crust and the mantle.
2. 19 13 Guetenberg discovered the nuclear-mantle boundary (CMB)->; The earth is stratified, which can specify the depth of the partition.
3. 19 15 meteorologist Wei Gena put forward the theory of continental drift based on geological evidence, which was not accepted because of the lack of power source for drift.
4. 1929 Holmes thinks that the thermal convection under the continental crust is the cause of continental division and drift, and puts forward the viewpoint of convergence and tension crack for the first time.
5. The marine crust was discovered in the period of1940s, with a thickness of only seven kilometers, which is different from the granite of continental crust.
6. 1954 Japanese seismologist wadati and American geologist Benioff discovered that there is an inland inclined wadati-benioff zones connecting the trench and the volcanic island arc, which is a pioneer of plate tectonic theory.
7. 1956 Owen and others measured the paleomagnetism of the land and found that if the magnetic pole was pushed back, the land would drift for a long time, and the moving path was very close to that described by Wegener.
8. 1959 Heezen and Tapp of Columbia University drew the first topographic map of the seabed based on the water depth data, which clearly showed the ridges and trenches.
9. 1962 Hess pointed out that mantle thermal convection caused the oceanic crust to extend outward from the mid-ocean ridge (MOR) and disappear into the trench, forcing the mainland to move horizontally. Plate theory has developed from the initial idea of horizontal movement to the idea that the movement inside the earth affects the surface.
In the 10. 1960' s, the paleomagnetic inversion schedule of the land was obtained, and it was also considered that the alternation of positive and negative magnetic poles on both sides of the ocean ridge should be caused by the lateral growth of the ocean crust.
1 1. Now, we have been able to grasp the age of ocean crust, the expansion speed of ocean ridges and the subduction speed of trenches around the world, and we can mark the shape, distribution, movement speed and movement history of plates.
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Plate distribution
At present, the world can be divided into seven plates-Pacific plate, Eurasian plate, African plate, Australian plate, North American plate, South American plate and Antarctic plate-and more than a dozen smaller plates.
The plate is actually the lithosphere, including the crust and a small part of the upper mantle. Therefore, there is no distinction between "continental plate" and "ocean plate", but it is named "continental plate" and "ocean plate" according to its composition.
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plate boundary
It is divided into extensional plate boundary, convergent plate boundary and dislocation plate boundary. Convergent plate boundaries are areas where plates are pressed against each other, which are characterized by trenches, volcanic island arcs and folded mountains. The boundary of extensional plates is an area where plates stretch each other, which is characterized by rifts and mid-ocean ridges in geomorphology. The boundary of dislocation plate is the area where two plates rub against each other.
Source: Longteng Culture Publishing House, edited by Professor Wang Zhiming of Basic Earth Science in Senior Middle School (full).
There are three modes of plate movement: convergence, divergence and conservation, which constitute three different types of boundaries. Convergent plate boundaries are mutually pressing plates, such as Himalayas, Central Mountains, Alps, island arcs, trenches, etc. Extend plate boundaries, such as mid-ocean ridges (offshore extension) and East African Rifts (onshore extension). The conservative plate boundary refers to the transform fault related to ocean ridges, whose movement mode is similar to the strike-slip fault on the surface, and its area has not changed, so it is called conservativeness.
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plate movement
The plate moves above the asthenosphere and is driven by mantle convection column.
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involve
* plate tectonic theory
* continental drift theory
* seafloor spreading theory
* mantle thermal convection hypothesis
From "blog.org/wiki/%E6% 9d% BF% E5% a1%8a"
Page Classification: Geography | Geology
Plate tectonics
Wikipedia, the encyclopedia of freedom
(adapted from plate tectonics)
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Plate tectonics, or "plate tectonics hypothesis", "plate tectonics" or "plate tectonics", is a geological theory developed to explain the phenomenon of continental drift. According to this theory, the lithospheric plates of the earth are assembled; The world is divided into six plates, and the positions of the sea and the land are constantly changing. According to this theory, the outermost layer of the earth's internal structure is divided into two parts: the outer lithosphere and the inner asthenosphere. This theory is based on two independent geological observations: seafloor spreading and continental drift.
catalogue
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* 1 Precambrian
* 2 Cambrian
* 3 Ordovician
* 4 Silurian
* 5 Devonian
* 6 Early Carboniferous
* 7 Late Carboniferous
* 8 Permian
* 9 Triassic
* 10 Jurassic
* 1 1 Late Jurassic
* 12 Cretaceous
* 13 Cretaceous-Tertiary extinction
* 14 Eocene
* 15 Miocene
* 16 Late Ice Age
* 17 modern world
* 18 future world
*19 65438+500 million years later
* 20.25 billion years later
* 2 1 source
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precambrian
Late Precambrian supercontinent and "Ice Room" World (650 million years ago)
1 1 100 million years ago, the Rodinia supercontinent began to split. The world in the late Precambrian is very close to the present climate and is an "ice room" world.
Rodinia split in half about 750 million years ago, forming an ancient ocean.
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Cambrian Period
Cambrian: the beginning of Paleozoic (565,438+400 million years ago)
For the first time in CAMBRIAN, a large number of hard-shelled organisms appeared. Shallow seas flooded the mainland. The supercontinent Gondwana began to form near the South Pole.
The Iapetus Ocean expands between the ancient Laurentia (North America), the Baltic Sea (Northern Europe) and Siberia.
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Ordovician period
The ancient oceans separated the continents (458 million years ago).
During the Ordovician, the ancient ocean separated Laurentia, Baltic Sea, Siberia and Gondwana. The end of Ordovician is one of the coldest periods in the history of the earth. The south of Gondwana is completely covered with ice.
Iapetus Ocean separates the Baltic Sea from Siberia, and the Paleotethys Ocean separates Gondwana, the Baltic Sea and Siberia. The pan-ocean covers most of the northern hemisphere.
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Silurian Period
In Paleozoic, the ocean closed and the continents began to collide (425 million years ago).
The collision between Laurentia and the Baltic Sea continent closed the northern part of God's sea and formed the "old red sandstone" continent. Coral reefs expanded and land plants began to cover the barren continent.
Continental collision formed the Caledonian Mountains in Scandinavia and the Apara Mountains in northern Great Britain, Greenland and the east coast of North America.
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Devonian Period
Devonian: The Age of Fish (390 million years ago)
In Devonian, the ocean closed in early Paleozoic, forming a "pre-Pangaea" continent. Freshwater fish migrate from the southern hemisphere to North America and Europe. Forests originally grew in ancient Canada near the equator.
Plants grew in large numbers, forming coal in today's northern Canada, northern Greenland and Scandinavia.
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Early carboniferous
Pangu continent began to form in the early Carboniferous (356 million years ago).
In the Early Carboniferous, the Paleozoic ocean between Europe, America and Gondwana closed, forming the Appalachian Mountains in Apara and the Variscan Mountains in Vilis. The Antarctic began to form an ice sheet, and quadruped vertebrates began to develop in the coal swamp near the equator.
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Late carboniferous
Late Carboniferous: The Great Coal Marsh Age (306 million years ago)
In the Late Carboniferous, the continent consisting of North America and Europe collided with Gondwana in the south, forming the western half of Pangea. Most of the southern hemisphere is covered with ice, and a huge coal swamp is formed along the equator.
Centered on the equator, Pangu continent extends from the South Pole to the North Pole, separating the ancient Mediterranean and the ancient ocean on the east and west sides.
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Permian Period
The end of Permian: the greatest extinction since ancient times (255 million years ago)
In Permian, a huge desert covered the western Pan-continent. At the same time, reptiles spread all over the supercontinent. 99% of the creatures disappeared in the extinction event, marking the end of Paleozoic.
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triassic
At the end of Triassic, Pangu continent was formed (237 million years ago).
Pangu supercontinent formed in Triassic allowed terrestrial animals to migrate from Antarctica to the North Pole. After the Permian-Triassic extinction, life began to diversify again. At the same time, warm water biota spread to the whole Tethys Ocean.
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Jurassic Period
Early Jurassic: Dinosaurs spread all over Pangea (65.438+0.95 billion years ago).
In the early Jurassic, Central Asia and South Asia began to form. The vast ancient Mediterranean separated the northern continent from Gondwana. Although Pangu is still intact, you can hear the rumble that the mainland began to split.
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Late Jurassic
Pangea began to split (65.438+52 billion years ago)
In the middle of Jurassic, Pangu began to split. In the late Jurassic, the middle of the Atlantic Ocean was a narrow ocean, which separated Africa from eastern North America. East Gondwana began to separate from West Gondwana.
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the Cretaceous period
A new ocean opened (94 million years ago)
The South Atlantic opened in Cretaceous. India separated from Madagascar, accelerated northward and crashed into Eurasia. It is worth noting that North America is still connected with Europe and Australia is still a part of Antarctica.
The global climate in Cretaceous was warmer than it is now. Dinosaurs and palm trees appeared in the Arctic Circle, Antarctica and southern Australia. Although there may be some ice sheets in the polar regions in the early Cretaceous, there were no large-scale ice sheets throughout the Mesozoic.
Cretaceous is a period of rapid basin opening. The rapid expansion of mid-ocean ridges has led to the rise of sea level.
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Cretaceous-tertiary extinction
The end of the dinosaur era (66 million years ago)
Hicksulubo hit the earth. The impact of this comet with a diameter of 16 km led to global climate change and the extinction of dinosaurs and many other species. In the late Cretaceous, the ocean continued to widen, and India approached the southern edge of Asia.
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Eocene Epoch
Early Cenozoic: India began to attack Asia (50.2 million years ago)
50 million to 55 million years ago, India began to attack Asia, forming the Qinghai-Tibet Plateau and the Himalayas. Australia, which was originally connected with Antarctica, began to move rapidly northward at this time.
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Miocene Epoch
The world presents a modern structure (6.5438+0.4 million years ago).
20 million years ago, Antarctica was covered with ice and snow, while the northern continent cooled rapidly. The world looks similar to modern times, but please note that Florida and parts of Asia are still under the ocean.
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Late ice age
30 million years ago, the earth entered the igloo climate (18000 years ago).
When the earth is in an "ice room" climate, both poles are covered with ice and snow. The polar ice sheet expands due to changes in the Earth's orbit (Milankovic cycle). The last polar ice sheet expansion occurred 18000 years ago.
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Modern world
There are clear climatic zones in the world today.
We have entered a new stage of continental collision and will eventually form a new Pangu supercontinent. The global climate is warming, because we are leaving the ice age and at the same time, because we are releasing greenhouse gases into the atmosphere.
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Epcot
This may be what the earth will look like 50 million years later (50 million years ago)
If today's plate continues to move, the Atlantic Ocean will widen, Africa will collide with Europe and close the Mediterranean Sea, Australia will collide with Southeast Asia, and California will slide north to the coast of Alaska.
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65438+500 million years later
The Atlantic Ocean began to close (1.500 million years ago)
A new subduction zone will be created along the east coast of North America and South America, which will consume the seabed that separates North America from Africa. 1 100 million years ago, the mid-Atlantic ridge will subduct and the continents will gradually move closer.
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250 million years later
The ultimate Pangea will be formed 250 million years later (250 million years ago).
The bottom of the North Atlantic and South Atlantic will be submerged under North America and South America, resulting in the second Pangea-"the ultimate Pangea". A small ocean basin will sink in the center of this supercontinent.
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data source
:: The ancient map project (www.scotese.com)c. r. Scotese plate tectonic map and continental drift animation.
From "blog.org/wiki/%E6% 9D% BF% E5% 9D% E6% 9E% 84% E9% 80% A0% E8% AE% BA"
Category: Geology