When did Li Siguang discover Quaternary glaciers?
[Blocked advertisement]
After these important discoveries, Li Siguang published papers such as Quaternary Glacier in the Yangtze River Basin and Quaternary Glacier Phenomenon in Huangshan Mountain, Anhui Province, and later published a monograph Lushan Mountain in the Ice Age. He proposed that Lushan Glacier can be divided into three glacial periods, the oldest being "Poyang Lake Glacier", which occurred in the early Pleistocene and was the largest, and the green gravel beside Poyang Lake was important evidence. Then came the "Dagu Ice Age", which belonged to the early Middle Pleistocene, represented by the ochre mud and gravel in Dagushan area. The relatively new one is the "Lushan Ice Age", which belongs to the late Middle Pleistocene, and its scale has been greatly reduced. After the founding of the People's Republic of China, some scholars suggested that the "Dali Ice Age" was later than the "Lushan Ice Age" and belonged to the late Pleistocene, represented by the moraine in Cangshan, Dali, Yunnan. In this way, the Quaternary has the above four glacial periods, which correspond to the four classical glacial periods proposed by German punk and brukner at the beginning of the 20th century based on the study of Quaternary glacial deposits in Alps.
Li Siguang's theory about Quaternary Glaciers in eastern China had collaborators and supporters in the early days, including a group of China geologists such as Li Jie, and foreign geologists, such as Fessman in Austria, Narifkin in the former Soviet Union and Miller in the United States. The existence of Quaternary glaciers in China has attracted the attention of international geologists.
Shi Yafeng, the pioneer of modern glacier research in China, questioned the existence of Quaternary glaciers in the middle and low mountainous areas in eastern China in the early 1980s. They believe that the so-called "ice bucket" in Lushan area does not have ice sill and ice bucket chassis topography, but is the result of the joint action of hillside block movement and running water erosion: "U-shaped valley" is a wide valley formed by running water acting on syncline valley or controlled by weak stratum; "Mud gravel" is the accumulation of gravity, ice-melting mud flow and ancient mud flow. They further concluded that the Quaternary temperature, snow line and area ratio of glacier accumulation area (AAR) in the middle and low mountainous areas in eastern China (below 3000m above sea level) were not suitable for glacier development. Whether there are glaciers in the Quaternary in eastern China has become an unsolved case. At present, this academic debate continues.
But in the west of China, there is no doubt about the existence of Quaternary glaciers. As early as the early 1940s, when the famous geologist Huang led the petroleum geological survey in Xinjiang, he studied the Quaternary glacial sediments at the southern foot of Tianshan Mountain, published two papers, expounded the evidence of the existence of ice ages, and divided them into three ice ages, represented by different moraines. The moraine series mentioned above can still be found today, and a consensus has been reached in the whole academic circle.
The appearance of glaciers has a great influence on the global climate and biological development, especially the Quaternary glaciers, which directly affect the living environment of human beings. Studying and confirming Quaternary glaciers has both special theoretical significance and universal practical significance, so it has always attracted people to make unremitting efforts.