科研之友
微信
新浪微博
Facebook
分享链接
摘要
Tuotuo River basin is one of the birthplaces of the Yangtze River，and its widely distributed perma? frost has an important impact on the process of production and confluence，ecosystem，and even regional climate in the source area of the Yangtze River. The investigation and understanding of the distribution and characteris? tics of permafrost in this region can provide basic data support for studying the interaction between permafrost and climate，hydrology and ecology in the source region of the Yangtze River. From October to November 2020，we carried out a 50-day field investigation of permafrost in the source area of Tuotuo River and arranged 32 boreholes in different underlying surface types，different geomorphic parts，and different altitudes，with a total drilling depth of 1，200 meters. This paper is a preliminary summary of the characteristics of permafrost and the development of underground ice in the source area of the Tuotuo River based on the data of drilling and exploratory pits. The results show that the permafrost in the source region of the Tuotuo River has formed some taliks under the influence of rivers and geothermal energy to a certain extent，and its lower bound of per? mafrost is roughly between 4 650 m and 4 680 m. The average permafrost table depth exposed by boreholes is （2. 47±0. 98）m，and residual thawed interlayers exist in some areas. Affected by lithology and geothermal of shallow surface sediments，the permafrost base depth exposed by drilling holes is relatively shallow，with an av? erage of 19. 3 m，and permafrost is relatively thin，with an average thickness of 15. 0 m. The maximum perma? frost base depth and thickness of permafrost revealed by drilling holes are 75. 0 m and 72. 7 m，respectively. To? pography，sediment characteristics，and geothermal conditions are the main reasons that affect the large spatial difference of permafrost thickness. The ground ice in the study area is mainly distributed at a depth of more than 15. 0 m. At the same time，the shrinking pingo and lithalsa are also found. These phenomena also imply that the permafrost in the study area is in the process of degradation.
- 单位
