The scenery of Taihu Lake is very beautiful. Do you know the cause of the formation of Taihu Lake? Scientists hav
The scenery of Taihu Lake is very beautiful. Do you know the cause of the formation of Taihu Lake? Scientists have only put forward several hypotheses to explore the causes of Taihu Lake, but which one is the real reason remains to be explored!
Taihu Lake, located in the southern edge of the Yangtze River Delta, was called Zhenze and Juqu in ancient times, and also called Wuhu and Lize. It is one of the five largest freshwater lakes in China, with a boundary of 30 55' 40 "~ 365 438+0 32' 58" north latitude and 65 438+065 438+09 52' 32 "~ 65 438 east longitude.
The water in Taihu Lake is shaped like a bergamot. Taihu Lake, as the center of the water network in the south of the Yangtze River, is rich in resources and has nurtured people in the basin. It has been called "wuyue" since ancient times. Scholars of all ages were even more intoxicated with it, leaving many well-known poems. Taihu Lake has beautiful scenery and rich products, and the nearby Yangtze River Delta is dotted with rivers and lakes, which has always been the land of plenty in China.
There are many peaks around Taihu Lake, and the famous tea Biluochun and Taihu Red Orange are the tributes of the ancient court. Taihu Lake is also rich in all kinds of aquatic products, among which whitebait in Taihu Lake, with crystal clear body and tender meat, is a delicious dish at the banquet. However, it is such a beautiful and magnificent Taihu Lake, which enjoys a good reputation at home and abroad, and its causes are still debated until today.
As early as the early 20th century, China geographer Ding Wenjiang and foreign scholar Haydenschm believed that the deposition of great rivers led to the formation of Taihu Lake. They pointed out that 5000 years ago, Jiangyin was along the coast, east of Jiangyin, south of Rugao and north of Haining, including Taihu Lake, which is a theoretical description of the origin of Taihu Lake.
In 1930s, due to the discovery of underground lacustrine and marine sediments in the lake area, the academic circles had a mature and systematic view on the formation of Taihu Lake. Famous geographers such as Zhu Kezhen and Wang Huzhen put forward the theory of lake genesis, which has been enriched into new contents in the future. In 194 1, Feschmann, a German, proposed that it would pass through Taicang, Jiading Waigang, Shanghai Maqiao and Jinshan Caojing and reach the vicinity of Wangpan Mountain in Hangzhou Bay. The coastline of the 3rd century. By measuring the carbon-14 of shell fragments under Maqiao cultural site in Shen Gang, researchers basically concluded that Shen Gang was an ancient coastline 6000 years ago.
Professor Chen from Haikou Institute of Geography, East China Normal University, etc. On the basis of summarizing previous studies, the lake theory is developed and perfected. This statement is mainly inferred from the existence of marine deposits in Taihu Plain, and it is believed that a large amount of sediment brought by the Yangtze River gradually accumulated in the downstream, which made the Yangtze River Delta at that time extend to the sea continuously, thus forming a sand mouth.
Later, the sand mouth gradually extended around the northeast bank of the ancient Taihu Lake, turned to the southeast, connected with the sand mouth on the north bank of Qiantang River, and surrounded the ancient Taihu Lake. Later, due to the continuous deposition of sediment, this lagoon gradually became a large and small lake completely isolated from the ocean, and Taihu Lake is the main body of these scattered lakes. After continuous desalination, it became today's Taihu Lake.
In recent years, with the continuous study of geology, geomorphology, hydrology, archaeology and literature in Taihu Lake area, especially in dozens of places 5,000 years ago? From the Neolithic sites 6000 years ago to the discovery of Han and Tang sites, many researchers questioned the problems existing in the lake theory. They think that in the process of seawater infiltration into the ancient land, although it is eroded and deposited at the same time, this situation is unbalanced for the whole ancient land. Although there are lake landforms in some places, it has no overall significance.
Therefore, although the lake theory can explain the topography and geological deposits of Taihu Plain, it is difficult to explain why there are Neolithic sites and paleontological fossils in the hinterland of Taihu Plain and under the peat layer at the bottom of the lake today, which is also inconsistent with the distribution range of Holocene continental strata. Therefore, many people suggested that most of Taihu Plain was originally land, so ancient residents could live together on it.
People speculate that it is around 6000? 10000 years ago, Taihu Lake was a flat plain where people once lived and lived. Because of the low terrain, the lake was finally full, and people were flooded before they could move things.
As for the formation of this depression in Taihu Lake, people think it is related to crustal movement. Taihu Lake area may always be a zone where the earth's crust is sinking. Because of the low terrain, the flowing water collected from all directions cannot be discharged in time, and naturally a lake is formed. The theory of "plain flooding" in Taihu Lake has not received more spread and response, and another theory of causes has suddenly appeared. Recently, a group of young geologists explained the formation of Taihu Lake with a brand-new view.
They boldly assumed that perhaps in the distant ancient times, a huge meteorite flew from outer space and landed in the position of Taihu Lake. In other words, the huge Taihu Lake turned out to be a meteorite! They estimate that this meteorite has caused a strong impact on the earth's crust, and its energy may reach the energy generated by the explosion of billions of tons of explosives, or equal to the energy of 65.438+million atomic bombs that exploded over Hiroshima, Japan.
Young people who put forward the "meteorite impact" hypothesis listed the following aspects of evidence:
First, from the external outline of Taihu Lake, its northeast is concave inward and its shore is very broken; In the southwest, it protrudes outward, and the lake rocks are very neat, like a smooth arc, which is very similar to the shape of craters left over from some foreign continents.
Secondly, the researchers found in the investigation that the rock fractures around Taihu Lake have amazing regularity. There are many tensile cracks in the rocks in the northeast of Taihu Lake, while the cracks in the southwest are mostly formed by extrusion. This abnormal situation of formation fracture will only appear when it is subjected to a huge impact from the northeast.
Thirdly, the researchers also found that there are breccia with very complex composition around Taihu Lake. Observing these rocks under the microscope, we can also see the metamorphism caused by the impact force. In addition, they also found a lot of cosmic dust and molten glass near Taihu Lake, which can only be produced under the impact of meteorites.
From the above evidence, they infer that the meteorite swooped down from the northeast. Because the southwest of Taihu Lake is just below the meteorite front, the impact force is the largest, so radioactive fracture occurs, while the northeast is subjected to tensile force, forming a tensile fracture perpendicular to the impact direction.
Due to the huge impact of meteorites, the rocks are broken, forming mixed breccia, and the rocks are impacted and metamorphic. At present, there is no unified understanding of the causes of Taihu Lake, but these different viewpoints are helpful to promote further investigation and research. With the deepening of exploration, I believe that people will eventually be able to uncover the mystery of the cause of Taihu Lake.