The earliest continental plate is called Rodinia, which was formed inProterozoic——Mesoproterozoic——Tonian The time is from about 1000 million years ago to 850 million years ago.First occurrence of large spines during the TertiaryCondensate source, forming the ancient continent（Rodinia Pangaea）。
Today there are seven continents on the earth, which was equivalent toGeological ageOfEdiacaran（Sinian）At that time, a supercontinent was formed. The continent began to split after 100 million yearsdevonianAt that time, due to the collision between continents, the continents on the earth were connected again about 245 million years ago, which was equivalent tothe triassic periodScientists call it Pangea.[2]
Distribution
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PangeaAfter three stages of division, the distribution of the present continent was formed.
The first stage: 180 million years ago, in the middle of Jurassic period.
The second stage: Due to the igneous activity on the east coast of North America, the northwest coast of Africa and the center of the Atlantic Ocean, North America is pushed to the northwest.
The third stage: the separation of South America and North America, forming the Gulf of Mexico, Antarctica andMadagascarThe volcanic activity on the border gradually generated the West Indian Ocean.
becausePlate movementWith continuous progress, geologists predict that the continent will form a supercontinent again, which is called Pangea Ultima, and is predicted to form in 250 million years.
Continental drift theory
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Continental drift theoryIt is believed that 200 million years ago, the existing continents on the earth were connected to each other, thus forming a piece ofPrimitive continent, or calledPangea。Pangaea is surrounded by a vast ocean calledPan ocean。180 million years ago, the Pangaea began to split and drift into two large blocks in the north and south. The southern block is called Gondwana, including South America, Africa, India and Pakistansubcontinent, Antarctica andAustralia；North BlockLaoya Ancient Land, includingeurasiaAnd North America.After hundreds of millions of years of vicissitudes, the Pangaea further split and drifted about 65 million years ago, forming Asia, Africa, Europe, Oceania, South AmericaNorth AmericaAnd Antarctica;The Pan Ocean completely disintegrated, forming the Pacific Ocean, the Atlantic Ocean, the Indian Ocean andarctic ocean。
Today's ArcticCanadian BasinIt was 80 million years agoCretaceousAt the end of the period, it began to appear due to plate expansion, andEurasian BasinYounger, just 53 million years old.thatPangeaWhy did it break up with the later Gondwana Ancient Road?Gondwana in its 500 million yearsevolutionIn history, whether it has ever been connected withLaoya Ancient LandOnce again aggregated intoUnited Ancient Land？How did they split, drift and converge step by step, and finally form the land sea pattern of the earth today?Geologists have even further traced how the earlier United Ancient Land was formed, and what was the earth like in the billions of years of history before the United Ancient Land?Their thinking extends to the formation of the earth, the evolution of celestial bodies, and even the essence of the universe.[3]
Plate tectonics
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On“Continental drift theory”, "mantle convection theory", and“Seafloor spreading theory”From 1968 to 1969, X.le Pichen of France, D.P. McKenzin of Britain and W.J. Morgan of the United States further considered the land and the sea floor together, and believed that the ocean floor and land were both part of the lithosphere, and then put forward a new continental tectonic theory -“Continental plate theory”。
The theory gives the distribution map of the world plates, which is divided into six plates, namely, the Pacific plate, the Eurasian plate, the Indian plate, the African plateAmerica and Antarctic Plate.Except that the Pacific plate is entirely oceanic crust, the rest of the plates are composed of continental blocks and ocean basins.
According to the plate tectonic theory, the relatively rigid plate blocks drift on the plastic asthenosphere of the upper mantle, and each makes large-scale horizontal movement due to the convection of the mantle flow and the expansion of the sea floor.The plates are separated and proliferated at the mid ocean ridge, subducted and subducted at the trench, and so on.There are three kinds of relative movements between plates: separation, convergence and translation (shear), which play the role of mutual tension, compression and friction.The interior of the plate is relatively stable, and its surrounding boundary is the zone where the lithosphere is relatively active, with relatively active seismic, volcanic and fault activities.The boundaries between plates are often tectonic active zones such as mid ocean ridges, continental rifts, islands, trenches and transform faults.
The theory of plate tectonics depicts a vivid picture of the earth, striving to grasp the laws of global geological movement as a whole.The theory immediately aroused great response after it was put forward, and was called "new global tectonic theory" by some scholars.The rise of new theories has been verified by a series of major discoveries in the fields of paleomagnetism, marine geomorphology, submarine structure, marine sedimentation, earthquake, etc., and has integrated the research results of various branches of solid earth science, which can better explain the global geotectonics and its evolution, effectively reveal the distribution law of minerals, and reasonably explain the global geothermal, geomagneticThe laws of earthquake and volcanic activity have answered some scientific mysteries that were considered difficult in the past, and thus have been recognized by most scientists in the world.[4]
