Over the past 50 years, especially since 1973, CAS has conducted a great number of large-scale expeditions to the Qinghai-Tibet Plateau (Tibet Plateau), involving scientists from various institutions and universities at home and abroad. These studies have scored fruitful achievements, which are playing an important role in social and economic progress, infrastructure construction, and ecological conservation of the region. To mark the 30 years research of the plateau, a symposium was held on Oct. 21 and 22 in Beijing.
With a total area of over 2.5 million square million kilometers, the Plateau is known as the “roof of the world” because of its unmatched elevation. Bordering the Pamirs in the west, Hengduan Mountains in the east, Kunlun-Qilian Mountains in the north and Himalayas in the south, it is one of the most unique geological regions on the earth. Its uplifting is one of the key events in natural history and therefore it is as an ideal geological unit for probing the formation and evolution of the lithosphere and the tectonic mechanism of the crust movement.
Since the late Cenozoic era, the Plateau's rise has imposed deep-going and far-reaching influence on the evolution and differentiation in the natural setting of its adjoining regions so that its natural conditions and ecosystems play a special role in the global change and is inseparable with the latter as its regional response to the global change is not negligible. Hence, the Plateau is the Mecca for scientists from various fields, like geology, biology, resources and the environment. In addition, the Plateau is the key for solving fundamental problems of geo-kinetics in the lithosphere and global change while the prospects for introducing sustainable development to the Plateau are both brilliant and promising.
A brief view of the Plateau-surveying history in retrospect
Since the later half of the 19th century, some foreign explorers and scientists came to the Plateau to conduct trekking expeditions in various forms. During the 1930s, Liu Sheng'e, Xu Jinzhi, Sun Jianchu and other Chinese scientists started exploring the flora, geography and geology of the Plateau. Their surveys were of positive significance in our understanding of the Plateau in a scientific way. But their work was fragmentary and scattered so that the majority of the Plateau was still unknown to us. After 1950, the surveying activities independently carried out by Chinese scientists on the Plateau came into a new era and as a result, world-renowned achievements have been accomplished in both theoretical exploration and applied research.
Since the 1950s, Chinese government has attached a special importance to the investigation of the Plateau's environment and natural endowment. In order to promote the Plateau's socio-economic development, it set requirements for making clear and evaluating the Plateau's natural conditions and natural resources, exploring natural calamities and their prevention. Hosted by either the central authorities or regional administration, both research bodies or industrial departments have organized various expeditionary teams for multi-disciplinary investigation and established permanent organs to conduct field observation, experimentation and on-the-spot research. During the 1950s and 1960s, a number of Chinese scientists were sent to carry out studies in the eastern part and heartland of Tibet, Qilian Mountains caught between Qinghai and Gansu provinces, Qaidam Basin, Kunlun Range, the vicinity surrounding the Mt. Qomolongma (Mt. Everest), Hengduan Mountains, central and southern parts of Tibet. At the mid-1960s, some mountaineering surveys were arranged and completed for the areas around the Mt. Xixabangma and Mt. Qomolongma.
In 1972, CAS formulated a Plan of Comprehensive Survey of the Plateau from 1973 to 1980, and in the next year, an expeditionary survey was organized to make its investigative work for the new stage, leading to an all-round and multi-disciplinary inspection of the Plateau in the whole decade of the 1970s. In the 1980s, a comprehensive survey was conducted to investigate the Hengduan Mountains, Mt. Namjagbarwa, Kara-Kunlun Mountains-Kunlun Mountainous Area and Hoh-Xil Wilderness, forming the first stage of the Plateau's comprehensive survey. During the 1990s, two CAS-sponsored projects were enlisted into the National "Pandeng" Program and the national network for key basic research projects under the titles of “A research on the formation, evolution environmental change and ecosystems of the Qinghai-Tibet Plateau” and the “Formation, Evolution of Tibetan Plateau withIts Environment and Resource Effects” respectively, forming the second stage of the surveying drive. In comparison with the first stage, the new move features its research direction exclusively spearheading to the research frontiers of the international community and poor links in the regional investigation in the past surveying activities, a transformation course from the qualitative exploration to a semi-qualitative and semi-quantitative one, from a static and typical approach to probes into the dynamic processes and related mechanisms, and from a uni-discipline to the multi-disciplinary teamwork and from regional research to its integration with the global change. The progress means the ever-deepening development of the research work.
Major scientific advances
The formation and evolution of the Plateau's lithospheric structure: A complete series of the Plateau's geological chronicles and several typical sections of stratigraphic samples of the top-ranking international renown have been established; characteristics of the Plateau’s tectonic structure and the crust’s deep mantle as well as the space-and-time distribution of magmatic rock belts and geological bodies are made clear; various hypotheses and models about the Plateau's formation, evolution and its rising mechanism in addition to the synthesized patterns for their dynamic mechanisms and coupling are developed.
The Plateau's uplifting process and changed environment: Since the collision between the Indian subcontinent and the Euro-asian Plate, the uplifting of the Plateau is a multi-staged and uneven process in variable speeds. So far, the Qinghai-Tibet region has roughly undergone three ground surface rises and two degrades during the Cenozoic era; since the turn between the end of Pliocene epoch and the beginning of the early Pleistocene epoch about 3.6 million years ago, the entirety of the Plateau experiences a drastic uplift. Data obtained from ice cores, lacustrine basin cores and loess sections show that the Plateau has its remarkable regionality and peculiarity in the context of the global environmental change.
The response of the East Asian monsoon to the Plateau's rise: Before the Plateau reached the half of its current elevation, the monsoon phenomena of near-earth wind in winter and summer were non-existent in the East Asian areas north to the 30 degree Northern Latitude. The uplifting effects of the Plateau on East Asian monsoon in winter is bigger than that in summer. Modern climate changes on the Plateau have experienced several stages: At the beginning of the 20th century, there was a cold period while in the 1980s, various areas on the Plateau came into a spell of sustained warmth one by one. The Plateau's northern tableland sees a bigger margin in the temperature fluctuation than that emerging in eastern China. So the Plateau is so sensitive that it may be regarded as a harbinger to herald the global climatic change in advance.
The biological zonation and man's adaptation to the Plateau's environment:The Plateau's uplift protects some time-honored biota and gives rise to some new floral and faunal species. The latter lead to new discoveries and new records in the taxonomic affluence of the Plateau. Because of the speciation of new taxa caused by the tectonic uplift, the Hengduan Mountains become a center for floral speciation and origin of new plant species in the world. As the Plateau has less oxygen in its air content, it becomes to be an ideal area for exploring the adaptability and physiological changes of low-land residents after they have come into the Plateau of high elevation.
The natural setting and regional speciation: The types, characteristics and formative evolution patterns of the Plateau's various elements in natural geography have been probed in an allround way. The distributive layout of the vertical structure in a mountainous ecosystem shows the enormous massif effect in connexion with the Plateau's heat sources, giving a full display to the spectacular sights of various land-based ecological phenomena such as vapor channels, dry ravines, frigid alpine shrubs and meadows as well arid cores in high elevations. Based on the distributive traits and regularities of the ground surface characteristics on the Plateau, it is divided into 10 natural belts with different distinctions.
Natural endowment, calamity reduction and regional development: The types, characteristics and distribution of various renewable resources on the Plateau are made clear basically and principles as well norms for evaluating the land use and performance of farming undertakings, forestry or livestock grazing farms are worked out in addition to the partial compilation of various land-use charts and maps. Based on long-term research of the distribution and occurrence patterns of various mountain hazards such as mudslides and snow-caused calamities, the schemes for their prediction, prevention and control are formulated. In the preparatory course of inaugurating the Plateau's natural reserves, the related research work plays a critical role. In the zonation of the Plateau’s agriculture, regional development plans for the middle reaches of Yarlong Zangbo River, Nyang Qu, and the Qamdo Prefecture have been completed.
