The research on Quaternary geological landforms in China mainly focuses on Quaternary glacial landforms, Quaternary geological landforms in coastal areas, Quaternary geological landforms in northwest loess areas, ancient humans, active structures and so on.
1. Study on Quaternary Glaciers and Paleoenvironment
Great progress has been made in the study of Quaternary glaciers since 1980s, including the investigation of Antarctic ice sheets and Arctic ice sheets, the study of the ice center on the Qinghai-Tibet Plateau, the study of mountain glaciers' cataloguing and glacier meltwater runoff, the glacier landforms in the west of China, and the new understanding of Quaternary glacier remains and environment in the east of China.
Scientists in China started their research on Antarctica late. 1982, Xie xianchu made his first wintering expedition in Kaixi station, and made a lot of detailed research on the ice core in the last ice age. By 2008, China has organized 24 Antarctic expeditions and established the Great Wall Station and Zhongshan Station. 1990, Qin Dahe made its first scientific expedition across the Antarctic continent, and studied the distribution characteristics of stable isotopes δ 18O, δD and excess deuterium (ex D) and their significance to paleoclimate records. These related studies show that the study of Antarctic glaciology in China has reached a new level. In July, 2004, China's first Arctic scientific research station, Yellow River Station, was built in New Olsen, Spitsbergen Islands.
At the same time, in the mid-1980 s, the ice core of Dunde ice cap in Qilian Mountain was studied, and more detailed evidence of Holocene climate fluctuation was obtained than other data such as sporopollen. 1992, Yao Tandong and others conducted an ice core study on the Gu Liya ice sheet (6300m, the largest ice sheet in Central Asia) in the West Kunlun Mountains, and drilled an ice core with a time span of over 654.38+10,000 years, which is of great significance for reconstructing the climate and environmental changes in the Qinghai-Tibet Plateau since the late Pleistocene.
China Glacier and Environment (2000), edited and published by Shi Yafeng, summarizes the important achievements of Quaternary Glacier and Environment Research in western China. During this period, some work has also been done on the controversy over the Quaternary glacial remains in eastern China. In the 1920s, Li Siguang proposed that there were Quaternary glacial remains in middle and low mountains such as Taihang Mountain, Lushan Mountain and Huangshan Mountain, which could be divided into four glacial periods. His ice age division has always been the standard of ice age division in eastern China. Since 1980, some glaciologists have put forward different understandings through a large number of field investigations on loess deposition, sporopollen analysis, vertebrate paleontology and red weathering crust (Shi Yafeng et al., 1989), and their achievements are reflected in the book Quaternary Glaciers and Environmental Problems in Eastern China. In recent years, the debate about Quaternary glaciers in eastern China has gradually cooled down.
2. Quaternary geological research in northwest loess area.
The breakthrough of Quaternary research in China lies in the progress of loess research in China, and the time series of Quaternary environmental changes has been established. At present, time series of various environmental changes have been established in the study of global change, among which China loess, deep-sea sediments and polar ice cores are the three pillars of Quaternary research. Loess has become an ideal carrier of Quaternary paleoenvironment and paleoclimate information because of its special geographical location and formation mode. The loess research in China has roughly gone through the following four stages.
Modern Loess Research The beginning of loess research in China is closely related to the participation of foreign geologists. /kloc-in the 9th century, R. Pumpelly opened the door to loess research in China, and he put forward the theory of loess lake deposition. Richthofen confirmed Pompeii's lake deposition theory and became the founder of loess weathering theory. Obruchev divided loess into hot loess and cold loess, which revealed the duality and regional significance of loess for the first time. Chinese geologists began to study loess from 1920. During the period of 1930, P. Teilhard de Chardin and Yang studied the stratigraphy and paleontology of loess. In this pioneering work, they divided the loess into two parts: Malan loess in the upper part and red soil areas A, B and C in the lower part; According to the ancient vertebrate fossils contained in it, the Quaternary can be divided into three stages: early, middle and late.
In 1950s, the new upsurge of loess research in China made great contributions to loess research in China, and Academician Liu Dongsheng did a lot of work during this period. 1957, Academician Liu Dongsheng and others separated old loess (earlier than Malan loess) and new loess (Malan loess and its later loess). He and Academician Zhang Zonghu (1962) named the early and middle Pleistocene loess Wucheng Loess and Lishi Loess, and they were named in 1964, 1965 and 65445. The research by Zhu Xianmo and Shi Yuanchun shows that the red band sandwiched between loess layers is essentially a brown soil type paleosol layer. This achievement gives people a new understanding of loess, thus confirming that the extremely thick loess plateau has been deposited in the form of sandstorm since 260Ma. In the middle of the dry sandstorm, there are many times when the climate becomes warm and humid, forming ancient soil. During this period, Academician Zhang Zonghu made a detailed study on the engineering properties of loess on the Loess Plateau.
Since 1970s, with the development of new disciplines and technologies, such as paleomagnetism, geochemistry, isotope geochemistry and chronology, loess research has entered the stage of combining observation with measurement experiment from naked eye observation. Magnetic susceptibility has been regarded as a climate substitute index to reflect the Quaternary environmental changes, and further promoted the global comparison of loess with deep-sea sediments and ice cores.
Since the mid-1980s, in the stage of quantitative and comparative research, Academician An Zhisheng proposed that loess and paleosol represent the winter monsoon and summer monsoon of paleoclimate environment respectively, focusing on the formation of loess and paleosol and the interpretation of their environmental information. Later, Academician Ding Zhongli used the ratio of particle content in loess and paleosol, and the particle size was 0. 002 ~ 0.0 10 mm is used as a proxy index of winter wind transport intensity. The grain size curve is consistent with the deep-sea oxygen isotope. Guo uses the ratio of weathering intensity represented by FeO and Fe2O3 in loess and paleosol as a proxy index of summer monsoon, and can also be compared with deep-sea oxygen isotope. Through comparative study, Academician Ding Zhongli found that the change of loess and paleosol sequence can almost be compared with the circulation of oxygen isotopes in deep-sea sediments since 6,543,800+0.8 million years, thus linking continental ice sheets and sea ice with inland climate change. 1985 Liu Dongsheng and others published the book Loess and Environment, which is a summary of the early research at this stage. Later, Zhang Zonghu and others published the book Loess in China (1989). Sun Jianzhong published Loess Research (2005), which discussed all aspects of loess.
At present, the research fields of loess mainly focus on grain size, paleontology, geochemistry, environmental magnetism and so on. The progress in these aspects indicates that the loess research in China has been in the leading position in the world.
3. Quaternary geology and geomorphology of Qinghai-Tibet Plateau
Although China organized four scientific expeditions to the Qinghai-Tibet Plateau in 1950s and 1960s, and achieved some remarkable results, due to the conditions at that time, the areas and contents of the expeditions were limited. 1973, China Academy of Sciences once again organized a comprehensive scientific expedition on the Qinghai-Tibet Plateau with a large team and extensive contents, and published the Series of Scientific Expeditions on the Qinghai-Tibet Plateau. Among them, the survey results of Quaternary geology and geomorphology are mainly reflected in books such as Quaternary Geology of Tibet, Tibetan Glaciers, Tibetan Geomorphology, and Time, Range and Form of Uplift of the Qinghai-Tibet Plateau, which is one of the most important achievements since the founding of New China.
From 65438 to 0993, the national climbing project "Study on the Formation, Evolution, Environmental Change and Ecosystem of the Qinghai-Tibet Plateau" led by academicians pushed the study of the Qinghai-Tibet Plateau to a climax again, made a series of significant progress, and published a series of studies on the Qinghai-Tibet Plateau. This paper summarizes the uplift process of the Qinghai-Tibet Plateau and its environmental changes, and the influence of the uplift process of the Qinghai-Tibet Plateau on the formation and development of the China monsoon, and puts forward three tectonic movements (Qinghai-Tibet Movement, Huang Kun Movement and Republican Movement) since 3.4 million years. The height of Qinghai-Tibet Plateau in different stages of Quaternary entered the cryosphere from 800,000 to 600,000 years ago and really developed into the roof of the world. The uplift of the Qinghai-Tibet Plateau has caused neotectonic movement around it, forming a series of active faults, among which the fault activity in the eastern margin is extremely strong, forming the north-south seismic belt with strong seismic activity in China, where the Wenchuan M 8.0 earthquake occurred on May 12, 2008.
Whether there is a large ice sheet in the Quaternary on the Qinghai-Tibet Plateau has been controversial. The focus is: first, has it ever existed? If so, in what era? These questions need to be answered later.
4. Study on the Yangtze River and Yellow River
The study of the Qinghai-Tibet Plateau has also led to the study of the formation and evolution of two major rivers in China-the Yangtze River and the Yellow River. The development history of the Yangtze River has always been a concern of geomorphologists. Shen Yuchang (1965) studied the geomorphology of the upper reaches of the Yangtze River and summarized the geomorphological characteristics of the Jinsha River basin. Yuan Fuli (1958) and Ren Meihua (1959) studied whether Shigu Bay in Jinsha River was captured by rivers. The connection of the Three Gorges of the Yangtze River is the key to realize the connection of the whole Yangtze River. The study shows that the breakthrough time of the Three Gorges should be from the late early Pleistocene to the early middle Pleistocene, and the study also shows that the whole line of the Jinsha River also occurred during this period. In 2006, Yang Dayuan and others published the book The Geomorphological Process of the Yangtze River, which summarized the geomorphology and formation process of the Yangtze River.
The study of the Yellow River has also made a series of progress during this period. The connection between Sanmenxia of the Yellow River and the Three Gorges of the Yangtze River has the same significance. Although many scientists have studied it, they have not reached an agreement on the connection time. Many scholars believe that the cutting of Sanmenxia occurred from the late early Pleistocene to the early middle Pleistocene, which is basically consistent with the cutting time of the Three Gorges of the Yangtze River. Secondly, several grand canyons in the upper reaches of the Yellow River flow through it. Longyangxia was connected about 6.5438+0.5 million years ago, and Zoige ancient lake disappeared in the late Late Pleistocene. At the end of the late Pleistocene, the Yellow River extended to the present source area of the Yellow River. In the late Pleistocene, the water system in the upper reaches of the Yellow River was greatly adjusted.
During this period, the relationship between the evolution of the Yangtze River and the Yellow River and the uplift of the Qinghai-Tibet Plateau was also studied.
5. The study of ancient humans
At the beginning of the 20th century, the discovery of "Beijingers" in Zhoukoudian, Beijing was considered as one of the two most important discoveries in the study of paleontology fossils in China in the 20th century. Her discovery not only filled the gap of ancient human fossils in East Asia, but also advanced human history by hundreds of thousands of years. More importantly, the earliest traces of human use of fire were discovered. Later, Qian Fang discovered "Yuanmou Man" (1965) in Yuanmou, Yunnan Province, which pushed the history of mankind to about 1.7 million years ago.
In the 1970s and 1990s, abundant Homo erectus fossils and stone tools were found in Hubei, Chongqing, Anhui, Jiangsu and Shaanxi, especially the "Jianshi Man" found in Jianshi, Hubei and the "Wushan Man" found in Wushan, Chongqing, which revealed the human history of China for more than two million years. These findings confirmed that eastern China played an important role in the history of human evolution. The discovery of hand axe in Baise basin, Hanshui basin and Lantian basin denied the existence of "Mohs line" and confirmed the existence of hand axe culture in East Asia.
Think about a problem
1) What is the value of studying Quaternary geology and geomorphology?
2) What can the development of Quaternary geology and geomorphology give us?
3) China's contribution to Quaternary geology and geomorphology?