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The reason for the high salinity of Qinghai Lake

Question 1: The natural geographical environment of the first land in western Qinghai. Why does Qinghai Lake have high salinity?

Qinghai Lake is a structurally faulted lake, and the edges of the lake basin are mostly connected by faults with the surrounding mountains. connected. The lake was first formed 200,000 to 2 million years ago. It was originally a large freshwater lake connected to the Yellow River system. At that time, the climate was mild and rainy, and the lake water was discharged into the Yellow River through the Daitang River in the southeast. It was an outflow lake. By 130,000 years ago, due to the neotectonic movement, the surrounding mountains were strongly uplifted. From the end of the Pliocene, the Riyue Mountain and the Bison Mountain in the eastern part of the lake rose rapidly, blocking the Daotang River that originally fed into the Yellow River, forcing it to flow from the east. It flows westward into Qinghai Lake, where Gahai Lake and Erhai Lake appear, and later separates into Haiyan Lake, Shadao Lake and other sub-lakes. [2]

Realm changes

Due to the blockage of the leakage channel, Qinghai Lake evolved into a closed lake. Coupled with the drying of the climate, Qinghai Lake has gradually transformed from a freshwater lake into a saltwater lake. In the Northern Wei Dynasty, the circumference of Qinghai Lake was said to be thousands of miles. In the Tang Dynasty, it was 400 kilometers, and during the Qianlong reign of the Qing Dynasty, it was reduced to 350 kilometers. There are ancient lake embankment ruins about 20 kilometers from the front edge of the Buha River Delta; Chahan City (built in the Han Dynasty), 25 kilometers away from the east bank of the lake, was originally on the lakeside. The east and west sides have retreated by 25 kilometers and 20 kilometers respectively, and the water level has dropped by about 100 meters. Qinghai Lake is oval in shape with a circumference of more than 300 kilometers.

In 1908, the Russian Kozlov speculated that the water level of the lake at that time was 3205 meters and the lake area was 4800 square kilometers; surveying data in the 1950s showed that the lake area of ??Qinghai Lake was more than 4568 square kilometers; 70 A topographic map published in the 1960s measured the lake level at about 3,195 meters. The lake area is 4473 square kilometers; in 1988, the water level was 3193.59 meters, and the lake area was 4282 square kilometers. In 2000, through remote sensing satellite data analysis, the area of ??Qinghai Lake was more than 4256.04 square kilometers. In August 2013, the area of ??Qinghai Lake was 4337.48 square kilometers. [3] The lake has a water volume of 73.9 billion cubic meters, a length of about 104 kilometers, a maximum width of about 62 kilometers, a maximum water depth of 31.4 meters, an average salinity of 12.32 grams per liter, and a salt content of 1.25%. [4]

For specific and related information, please refer to:

Qinghai Lake (Qinghai Lake, Qinghai Province)_Baidu Encyclopedia

baike.baidu/...WSV1si

Question 2: Is the concentration of salt higher in Qinghai Lake or the sea? The salinity of the sea is higher than that of Qinghai Lake.

The average salinity of the sea is 3.5%, while the salinity of Qinghai Lake is 1.5%.

Question 3: What are the factors that affect the salinity of a lake? The reasons that affect the salinity of a lake: It is mainly related to the water chemical composition of the lake (such as Mg 2+ , Ca2+ , Sr2+ , S r/Ca , Mg /Ca, etc.), but the role of these inorganic ions is also affected by other factors, such as the geographical environment (Qinghai Lake, Qinghai-Tibet Plateau, Dongting Lake), which is a very professional topic