The idea of continental drift appeared as early as the beginning of19th century, which was originally put forward to explain the obvious correspondence between the two sides of the Atlantic Ocean. It was not until 19 15 that the German meteorologist Alfred Wegener's The Formation of the Continent and the Ocean came out, which caused a shock in the geological field. In this immortal book, Wei Gena proposed that there was an ancient land on the surface of the Mesozoic earth based on a large number of evidences such as fitting the shape of the continent, paleoclimatology, paleontology, geology and paleopolar migration. Later, after more than 200 million years of drift, it split into the present ocean and land.
Because of the limited understanding of the internal structure and dynamics of the earth at that time, the mechanism of continental drift and dynamics could not be supported by physics. The unfortunate thing about Wei Gena's theory is that he advocates continental drift, but at the same time he thinks that the seabed is stable. Until 20 years after his death, people's interest in continental drift revived by abandoning the theory of submarine expansion of submarine stability.
Early maps of the world clearly showed the zigzag fitting of the relative coastlines of Africa and South America. As early as 180 1, A.Humboldt and his contemporary famous scientists suggested that the coastlines and rocks on both sides of the Atlantic are very similar. Wei Gena first proposed that the continental slope edge in deep sea should be applied to continental fitting. S.W.Carey proved that the contour lines of the two continents can be almost completely fitted at the isobath of 2000 meters below the sea surface. With the help of computer calculation, E.Bullard and others found that there was little difference in fitting results whether using 1000 m isobath or 2000 m isobath. The restoration and fitting work proves that all continents can be restored to form a supercontinent, namely "Pan-continent" named by Wei Gena. Pan-continent is a compound ancient continent composed of Gondwana (southern continent plus India) and Lauea (North America and Eurasia).
When Wei Gena first put forward the idea of continental drift, a lot of evidence came from his study of paleoclimate. He noticed that all continents have rock types formed in a certain geological period, which should not appear under modern conditions: for example, ancient coral reefs and tropical plant fossils are distributed in the polar regions; Ancient ice was found in the equatorial region. Wei Gena applied the principle of "making the past serve the present", and put the center of glacier activity near the rotating pole at that time, while the distribution areas of coral reefs and evaporites were near the equator. Thus, the ancient latitudes of the continents at that time were determined. By comparing ancient latitudes with modern latitudes, Wei Gena came to the conclusion of continental drift.
Wei Gena believes that continental drift provides the best explanation for the striking similarity between animals and plants on modern continents separated by oceans. Some examples that impressed Wei Gena and later investigators are: Mesosaurus, a freshwater reptile with a skeleton structure similar to salamanders, which can be seen in South America and Africa and cannot swim across the ocean; The fossil assemblage of Paleozoic marine invertebrates on both sides of the Atlantic Ocean is very similar. There are many terrestrial reptile fossils in Triassic in Antarctica, and so are other continents. The fossil seed fern of Permian Tongue fern flora (a unique plant combination) is found in all continents of South China and India. The evidence of paleontology has caused controversy. In 1967, Dietz published a comment on controversial evidence, including some interesting charts produced by Holden.
Nowadays, these arguments are traces of history, from which we can see that it is futile to collect new facts with the old framework, and it often leads to absurdity to explain facts with the old theory.
Wei Gena was impressed by the similarity of strata in South America, Africa, India and Australia. Geological phenomena on both sides of the Atlantic further prove that the two continents were once connected.
On two continents on both sides of the North Atlantic, there is a very important ancient mountain system called Caledonian Mountains. Today, Norway on the east coast of the Atlantic Ocean sees the western section of the mountain system, which seems to be submerged under the Atlantic Ocean after crossing Ireland. However, in Newfoundland, Canada, there is an ancient mountain system that seems to have climbed from the Atlantic Ocean. It has many similarities with the Caledonian Mountains in Europe. This mountain system that appears in North America is called the Old Appalachian Mountains. Wei Gena believes that the Appalachian Mountains in North America were once connected with the Caledonian Mountains in Europe. If the continents are pieced together, a continuous mountain system will be formed.
Rocks contain magnetic minerals, which were magnetized when they were formed under the influence of the earth's magnetic field, thus preserving the paleomagnetic records of the direction of the earth's magnetic field when they were formed and where they were formed. By measuring the inclination and inclination of the paleomagnetic field recorded by rocks, the position of the earth's magnetic pole can be calculated when rocks are formed.
People have measured the positions of thousands of ancient magnetic poles from the strata of different periods in various continents, and the line connecting the ancient magnetic poles of any continent in different periods is the apparent pole shift curve of that continent. Comparing and adjusting the apparent polar shift curves of various continents, the results show that all continents were pan-continent 200 million years ago.
Wei Gena eventually died looking for evidence, and his body was found the next year.