Excerpt from China Geography , China National Geographic Magazine

Magical Petrified Wood aired on January 9.

In the 70s of the last century, petrified wood was discovered by local farmers in the mountains of Yanqing County, Beijing, attracting the attention of geologists. As a result, experts began a 30-year scientific expedition, and finally determined that petrified wood was conceived in the Jurassic period 100 million years ago, and its formation was the result of hundreds of millions of years of complex geological movements and external forces. This film will follow geological experts to explore the mystery of the origin of petrified wood.

The Mystery of the Grand Canyon aired on January 8.

The Grand Canyon of the Dadu River in Sichuan is 2,675 meters deep, making it one of the deepest Grand Canyons in the world. Because of the depth, on both sides of the canyon, well-preserved and fully exposed rock formations of different geological eras are neatly arranged from the valley floor upwards. The rock is rich in paleontological fossils, and is a complete and vivid "textbook of geology and biological evolution", with a perfect geological profile of thousands of meters, recording the history of geological evolution for more than one billion years.

Approaching the Qionghai Volcanic Group" was broadcast on January 7.

In the 90s of the last century, when Bai Zhida, a geological expert, investigated the Qionghai area of Hainan, he accidentally discovered that there are a large number of ancient volcanic relics near Haikou, and the forms and types of volcanoes are very rich. After more than ten years of investigation, Bai Zhida and Hainan geologists determined that there had been large-scale volcanic eruptions in the Qionghai and Zhanjiang areas during the Cenozoic, and drew a map of the distribution of ancient volcanoes in this area, which provided a detailed basis for further research on the evolution of the Qiongzhou Strait.

The Mystery of Red Rock Falls aired on January 6.

There is a waterfall with a width of more than 50 meters in Lake Biwa in Dahong Mountain, Suizhou City, Hubei Province, and it is very surprising that the waterfall is not composed of water, but of reddish-brown rocks. This geological wonder attracted Professor Li Jiangfeng of China University of Geosciences and his delegation to visit. With the deepening of the investigation step by step, the mystery of the formation of the red rock waterfall was revealed step by step, and the geological changes of the sea to mulberry fields in hundreds of millions of years in Dahong Mountain also surfaced.

Last night, I came to the periodicals room of the school reading hall bored, and picked up two books: "Tourism Journal" and "China National Geographic". I casually looked at the table of contents of one of the books, and I felt that there seemed to be nothing good about that "Tourism Journal".

China National Geographic" is not bad, it has the "thirteenth goddess" of Gnie - Gnie Mountain, Xinjiang's red crops, and salt roads ......But what attracted me the most was "It's Hard to Believe that China Has Found a Large Number of Abandoned Old Holes"! Isn't it true that we in China regard respecting the old and loving the young as our traditional virtues? How can there be an abandoned old cave???

I looked down with a whole bunch of question marks. In China's Hubei and other places, a large number of abandoned old holes, their existence and the local widely spread legend of abandoning the old, the Chinese nation's tradition of respecting the elderly.

The reason why the lake can not be enclosed for land is that the lake is also an ecosystem, and the large-scale enclosure of the lake will shrink the lake surface and affect the entire ecosystem, and some lakes also have the effect of flood control. For example, Dongting Lake in Hunan and Poyang Lake in Jiangxi Province are located along the Yangtze River, and when the rainy season comes, the water level of these two lakes rises to reduce the water level along the Yangtze River. When the Yangtze River encounters a dry season, the water level of the Yangtze River drops, and the water level of Dongting Lake and Poyang Lake also drops to replenish the water level of the Yangtze River.

Lakes and rivers also function like wetlands. For example, it can provide an intermediate stop for migrating birds to rest. Lakes provide an environment for the development of fish, if maintained for farming.

This will lead to a reduction in biodiversity.

2.In the early stage of maintenance and cultivation, crops will be abundant because the land is fertile, but over time, the fertility of the land will also decline rapidly.

3.Some wetlands have been developed into farmland, and when the rainy season comes, the lake floods farmland and houses.

4.During the dry season, the water level drops quickly, and there are some dangers in the operation of the river. Some shoals will appear. It may cause accidents such as landing on the reef.

5.After the enclosure of the lake, the cooling effect of the lake weakened. This can lead to much warmer than normal temperatures.

If my opinion is uneven, don't blame me. Hope it can help the landlord. If there is any geographical problem. Can hi me.

Although land reclamation from lakes and sea can increase a certain amount of cultivated land, a large amount of farmland reclamation from lakes is easy to cause flooding, affect water quality, destroy vegetation, and cause soil erosion.

In the middle reaches of the Yangtze River, a large number of lakes have been enclosed for farmland, and the area of Dongting Lake has declined rapidly from the original largest freshwater lake. Other freshwater lakes are also rapidly decreasing in size, and some have disappeared altogether. These lakes play a role in water conservancy to receive the flood of the Yangtze River, and the reduction of the lake area directly leads to the lack of space for the diversion of the Yangtze River water, which can easily cause flooding.

The floods of '98 also had something to do with this.

The land reclamation of the sea makes the tidal range of the seawater smaller, the scouring capacity of the tide is reduced, the tidal volume in the port is reduced, and the self-purification ability of the seawater is also weakened, resulting in the deterioration of water quality, and the land of land reclamation is mainly used for urban construction and industrial and agricultural production, and there are more pollutants, especially all kinds of sewage are directly discharged into the sea, resulting in the possibility of eutrophication of seawater is greatly increased, and the probability of causing red tide is also greatly increased, which brings great harm to the coastal marine aquaculture industry and marine fishery production.

China's total cultivated land area is still relatively large, but based on China's large population, China's per capita cultivated land area is small. However, China's sea area is vast, the coastline is long, and the marine resources are abundant. Blindly enclosing lakes and seas to create fields will only destroy the balance of the environment and destroy the ecology.

Moreover, there is no crisis in China's grain production at present, so there is no need to enclose lakes and seas to create fields.

"China's cultivated land area is small, and the per capita arable land is insufficient. ”

This statement is inaccurate. China has a vast land area and a wide area of cultivated land, but due to the large population base, the per capita cultivated land area is small.

However, although the reclamation of land from lakes and the sea seems to be beneficial in the short term, it has been proved by reality to be a kind of damage to the bad environment, especially the reclamation of fields around lakes, which is a great destruction of the ecology. Therefore, various countries have already withdrawn these measures, and China has also implemented the practice of returning farmland to lakes in the Dongting Lake area and returning farmland to forests in other areas. This is the embodiment of practicing the scientific concept of development and adhering to sustainable development.

We are alleviating the pressure on food through scientific research and development of new varieties, and the control of the population can also effectively achieve the optimal use of resources.

You.. Are you kidding? First of all, do you know the role of the lake? Regulating the climate, flood distribution, etc., it is even more impossible to enclose the sea, not only do you need good conditions in the sea, but also the cost is quite high.

In addition, the cultivated land area is small, and the per capita cultivated land is insufficient, can it be solved by simply enclosing lakes and reclaiming land from the sea?

The most important thing is that too many wetlands have been destroyed, resulting in a sharp deterioration of the environment, the reduction and extinction of fishery resources, and a large number of plants and animals. Pronoun:"Forests are the lungs of the earth, and wetlands are the kidneys of the earth"Shouldn't it protect the kidneys?