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冰川冻土 ›› 1983, Vol. 5 ›› Issue (3): 37-46.

• 研究论文 • 上一篇    下一篇

天山博格达峰北坡冰川的成冰作用

谢自楚1, 王仲祥2, 张文敬1, 伍光和1   

  1. 1. 中国科学院兰州冰川冻土研究所;
    2. 兰州大学
  • 出版日期:1984-11-25 发布日期:2012-04-26

Ice Formation of the Glaciers on the Northern Slope of Bogda, Tian Shan

Xie Zichu1, Wu Guanghe2, Wang Zhongxiang1, Zhang Wenjing1   

  1. 1. Lanzhou Institute of Glaciology and Cryo pedology, Academia Sinica;
    2. Department of Geology and Geography, Lanzhou University
  • Online:1984-11-25 Published:2012-04-26

摘要: 中国大陆性冰川的成冰作用主要是在粒雪层的冷暖状况交替时期进行,并以融水下渗-再冻结作用为主要方式[1-5]。通常根据雪层厚度、冷储量、融水量、渗浸深度和它们之间的比例关系区分冷渗浸-重结晶、渗浸、渗浸-冻结等成冰类型,并划分相应的成冰带。本次考察中,我们试图了解博格达峰北坡冰川成冰作用的特殊性,独特的成冰带谱结构以及二十多年来气候变化在成冰过程中的反映。观测主要在四工河4号冰川及古班博格达扇状分流冰川上进行。

Abstract: This article tries to give a description of the peculiarity of the ice formation of the glaciers on the northern slope of Bogda, its unique belt pattern structure and the reflection of climatic changes on ice formation process in the last twenty years.In the area investigated, the temperature is low and the precipitation high, providing cold storage and material sources favourable for ice formation. At the same time, the existence of paleo-peneplain at about 4000 m a. s. 1., close to the snow line of the modern little ice age, is advantageous for the formation of mature cirques or firn basins on it.Because the glaciers are comparatively stable at present, the firn line and the zero-equilibrium line are more suited to the landforms. The surface slope of the glacier at its height is very small, therefore infiltration-congelation belt widely develops with its width far more wider than all other glaciers in the source area of the Urumqi river. The infiltration-congelation belts grow on the gentle passes at about 4100 m a. s. 1., forming inversion phenomemon of ice formation belt.In the past it is believed that the thickness of the firn layer of the infiltration belt in the eastern Tian Shan is less than 5 m. According to data from drilling, the authors found that it may reach 10 m thick, i. e., close to the bottom of active layer. This shows that on the profile of the firn layer there must be many annual layers and that the time of ice formation lasts also much longer than 2-4 years as estimated in the past.Frequent avalanche and avalanche cone and accumulation of snow drift in Bogda Mts. arc important supply source for the glaciers. Melt water from the surface of the avalanche cone can make the temperature of the firn in the active layer reach 0℃ in summer, shewing a thermal infiltration in ice formation. Temperature turns back to negative in the winter and a cold infiltration ice formation appears again. In view of the above, the authors suggest a conception of the ice formation in the form of an avalanche cone.