When did Tanggu become land?

In the 20th century, the global population increased sharply, the economy prospered unprecedentedly, the consumption of land resources and energy accelerated, and the environmental quality declined rapidly, which reached an unbearable level. What is the way out? Many countries have turned their eyes to the vast sea. "2 1 century will be the ocean century", which has become the consensus of the international community. Developing Bohai Sea will be a key step for Tianjin's future development.

Bohai basin has experienced many vicissitudes.

Looking at the Bohai Sea from space is like a dove spreading its wings and flying to Tianjin. Bohai Sea is surrounded by Liaodong Peninsula, Liaohe Plain, East Yanshan, North China Plain and Shandong Peninsula, and only Jiaoliao Strait is connected with the Yellow Sea in the east. The Bohai Sea is 550 kilometers long from north to south, 346 kilometers wide from east to west, with a coastline of 3,700 kilometers and a water area of1.300 million mu. It is a semi-closed inland sea. Because it is the northernmost sea in China, it was called "North Sea" in ancient times. It is also the geographical center of Bohai Economic Zone, one of the three coastal economic zones in China.

Bohai basin began to form at the end of Mesozoic 65 million years ago. Strong tectonic movement took place in North China, and the crust was stretched and thinned into several blocks. Some plots have risen to mountain plateaus, such as Yanshan, Taihang Mountain, Jiaodong and Shanxi. Some blocks sink into rift basins, such as Bohai Sea, North China Plain and Songliao Plain. The sediments washed down by rivers in mountainous areas are deposited in the basin, forming a Cenozoic stratum with a thickness of several kilometers, and the central Bohai Sea is the thickest, reaching 10 km.

Bohai basin is an inland closed basin, which has not been connected with the open sea for a long time. Until 2.5-5 million years ago, strong crustal movement disconnected Liaodong and Jiaodong blocks, forming a strait and long island chain, and the Bohai Sea was connected with the open sea. 1During the Great Ice Age from 2000 to 2.5 million years ago, the global sea level dropped sharply130m, and the Bohai Sea and the Yellow Sea became land. For a long time, Bohai Basin was covered by yellow sand. Until1.20 thousand years ago, the ice age ended, the temperature rose, the sea level rose, and the Bohai Sea resumed its blue waves. The coastline once reached Baodi, Wuqing and Jinghai. At that time, Tianjin was still a Wang Yang.

Many fossils of whales and dolphins were dug up in the soil around Baodi and Ninghe River. The sight of whales and dolphins cruising in Tianjin thousands of years ago is hard for modern people to imagine, but it did exist.

In recent thousands of years, the Bohai Sea has gradually retreated to the coastline of the Song Dynasty to the salt water selling area, and to the coastline of the Ming Dynasty to Tanggu District. "Vicissitudes" is the best way to describe the Bohai Sea.

Rich in resources and superior location.

The thick Tertiary strata in Bohai Basin are rich in oil, natural gas and geothermal resources, and the proven oil reserves of several oil fields in Bohai area account for about half of the country. Bohai Sea is the area with the highest geothermal flow value in North China, and the high-temperature hot water has not been explored and developed, so far it is unknown. Bohai Sea is also rich in chemical raw materials. At the beginning of the 20th century, Li Yong Soda Factory, the first modern chemical enterprise in China, was located on the Bohai Sea. It is no exaggeration to say that Bohai Sea and Tianjin are the cradles of China's chemical industry. The Bohai Sea provides shipping convenience for relevant coastal ports, and the drowning valley in the Bohai Sea provides the possibility of building a deep-water port. It also provides space and biological resources for mariculture. For example, adzuki bean crab is an excellent feed for protein. There are abundant fresh water and hot water resources in the seabed strata of Bohai Sea, which can provide high-quality drinking water and heating for artificial islands and offshore platforms in the future.

Unique natural and cultural heritage

Historical changes have left a large number of natural and cultural heritages for the Bohai Sea. The long island chain in the east of Bohai Sea and the phenomenon of mirage and dragon water absorption that occurs every year are natural wonders, which are very rare in other areas. The granite cliffs and beaches in Beidaihe are beautiful and quiet. The ancient coastal remains of Tianjin-Huanghua shell dike are rare at home and abroad.

Legend has it that Qin Shihuang had been to Beidaihe in order to seek immortality and yearn for the sea. Cao Cao's poem "Jieshi in the East, Watching the Sea" during the Three Kingdoms period is evidence. Temple Island has the relics and legends of Li Shimin's crusade in the Tang Dynasty and the Eight Immortals crossing the sea in the Song Dynasty.

The hometown of Han Yu, a great writer, is also on the coast of Bohai Sea. Shanhaiguan and Laolongtou are the starting points of the Great Wall in Wan Li, and historical figures related to the Great Wall, such as Meng Jiangnv, Liu Bowen, Qi Jiguang and Yan Song, have left their footprints. Historical figures such as Li Hongzhang, Yuan Shikai and Liang Qichao are all closely related to Tianjin. Li Dazhao, one of the founders of China * * * Production Party, was born in Bohai Sea. A famous saying written by Chairman Mao on the Bohai Sea is now engraved on the huge granite stone on the bank of Beidaihe. These are extremely valuable tourism resources.

Develop Bohai sea

Take care of Bohai sea

Bohai Sea is shallow, generally 10 to 30 meters, and the deepest point near Beihuangcheng Island is 50 to 70 meters. Shallow water makes the wind and waves small, which is suitable for building offshore construction facilities such as artificial islands and has broad prospects. But the Bohai Sea also has weaknesses, including at least three major problems.

The first is environmental pollution. More and more industrial and agricultural wastewater from coastal areas without environmental protection treatment is finally injected into the Bohai Sea, making the Bohai Sea a sea that hides evil and practices evil, while the Bohai Sea is a semi-closed inland sea with only a narrow strait to communicate with the outside world, with poor self-purification ability and basically more pollutants. Environmental testing data show that the most serious marine pollution in China is the Bohai Sea. Therefore, when developing and utilizing the Bohai Sea, we must pay special attention to environmental protection and restore its good natural ecological environment.

The second is the problem of sea level rise and storm surge. According to the sea level bulletin of the State Oceanic Administration, the sea level in the Bohai Sea rises by an average of 2 mm per year. After 50 years, it will rise by 0. 1 m, and when astronomical tides and large easterly winds are superimposed, storm surges will be generated, resulting in tsunamis.

The third is the earthquake problem. Bohai Sea is the place with the thinnest crust, the highest geothermal flow value and the largest tectonic movement energy in North China. The largest active fault in North China, the Tanlu fault, runs through the Bohai Sea from south to north, and the most frequent earthquake in North China is here. 1888 and 1969 are very close to each other, separated by 86549.

These are natural and man-made disasters, so we should pay full attention to them in Bohai development projects to avoid losses. The sustainable development of economy and society is the principle of modern construction and development, and development is the last word. We should face up to these problems with a positive attitude and start to solve them. The development of Bohai Sea will greatly promote the research and protection of Bohai Sea.