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冰川冻土 ›› 1983, Vol. 5 ›› Issue (3): 209-216.

• 研究论文 • 上一篇    下一篇

天山博格达峰地区冰碛物细碎屑的岩矿特征

唐永仪   

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

Mineriat Characteristics of the Fine-Grained Moraine in Bogda Region, Tian Shan

Tang Yongyi   

  1. Lanzhou Institute of Glaciology and Cryopedology, Academia Sinica
  • Online:1984-11-25 Published:2012-04-26

摘要: 中日联合天山博格达峰地区冰川考察队在考察期间采集了许多冰碛样品,笔者选择了约40个样品进行了0.25—0.01毫米粒级的偏光显微镜轻重矿物鉴定和选择性粒级磨圆系数测定,并结合郑本兴等人对野外各时代冰川沉积的介绍,参考有关文献,讨论本区冰碛岩矿组合的一般特点及其分布规律。

Abstract: Based on the polarization microscopic analysis of moraine in grain size 0.25-0.01 mm in Bogda Region, the characteristics of its fine-grained fragment component may be summed up as follows:1. General characteristics (1) Complexity of moraine component. It consists of more than 40 kinds of light minerals, heavy minerals and rock debris, one of the characteristics of glacial deposits in moraines of Himalaya and Tian Shan mountains.(2) Low maturity of moraine minerals. Shown in the high rate of heavy components and unstable heavy minerals, low index of maturity in minerals (<2), weak weathering, poor sorting, low index of roundness (2-3), etc.,another characteristic of glacial deposits.(3) Wavy valley shape of roundness index curve particular to glacial moraine deposits.2. Regularity of regional distribution of fine-grained components.The content of acanthconite on the top of Mt. Bogda is higher than that on the northern and southern slopes. The content of pyroxene and amphibole on the northern and southern slopes is higher than that on the top of Mt. Bogda. The type of mineral groups is simple on the top of Mt. Bogda and on the southern slope, but complex on the northern slope, reflecting mineral distribution as mentioned above shows the closer relationship of the glacial sedimentation to bedrocks in Bogda region than that in other localities.3. Mineral characteristics of moraine in different glacial perieds.(1) In the moraine from ancient to actual, the contents of heavy component and unstable heary mineral change from low to high, and the contents of stable heavy mineral and ZTR value vary from high to low. It .shows that mineral maturity of ancient moraine is higher than the modern moraine. This characteristic may be taken as the basis of glaciation division.(2) The mineral composition of moraine changes from complex type to simple as the moraine turns from ancient to modern. This regularity correspounds to different glaciations and their dimensions, clear evidences of development and decline of glaciers.