青海可可西里地区综合科学考察再报

A SECOND REPORT ON INTEGRATED SCIENTIFIC EXPEDITION IN HOHXILSHAN REGION,QINGHAI PROVINCE

1990年5月21日—8月23日再次考察了青海可可西里地区,在当地地质地理特征,自然地域的分异规律、晚新生代以来自然环境的演化和发展趋势、生物区系的组成及其演变,以及高山医学等多方面的研究,均取得了详实的第一性资料和重要进展。

The Present expedition was organized by Stata Scientific and Technological Commission (China) ,the Chinese Academy of Sciences,the Chinese Environmental Protection Agancy and the People's Government of Qinghai Province. After the past expedition in 1989,the Integrated Scientific Expedition,in this year, constituted by 68 persons of over 20 specialities from 34 different units, made a second expedition in Hohxilshan Region from May to August. The explorers, according their own disciplines,geology,geography and biology,have been divided in to three groups and set up 11 camps along the exploring route. The primary results are as follows:Hohxilshan,located at 34°00′-36°00′N and 89°30′-93°00′E,is situated in the center of the hinterland of Qinghai-Xizang Plateau. It is 250-400km long (east-west) and 200km wide (south-north)and occupies an area of 75,000km2.In Hohxilshan Region,there exist 10 groups or beds of palaebiological fossils from Triassic Period to Quaternary Perid and 5 belts of magmatic rocks. The section of marine deposits of Jurassic System was found in the east toward Ulan U1 Lake,and the fault zone composed by ophiolite complex.occurres in Xijir Ulan Lake,which indicate- there exist the suturing strip of Tethys. Meanwhile,the volcanic rocks of Genzoic Era is commonly distributing in north and east Hohxilshan,but no active volcano was discovered except 6 active fault belts.In Hohxilshan Region, the altitude is generally over 5,000m high,and the plateau plain is preserved inact,in which consists of 95% frozen zone and the frost reaches about 60-70m deep. This region is mostly covered with alpine steppe,but there occur alpine meadon in its south and alpine desert steppe in its west and north because of drying from southeast to northwest. This expedition also shows there is no united glacial sheet during Quaternary Period.In Hohxilshan Region,there are 19 species of big animals, 40 of brids,6 of fishes, 300 of insects and 250 species of higher plants,being 70 genera and 27 families,among which 4 new taxa may be determined. The biological floristic characters can be concluded as. 1. fewr species, but consisting of most endemic elements to Qinghai- Xizang Plateau; 2. great large population numbers. In addition, 68 explorers were studied for highland medical science and more than 20,000 data have been acquired already in the fields.