摘要
本文通过对豫西罗圈组3条剖面、30多个样品的粒度参数及粒度频率分布的研究、综合分析国内外典型冰碛岩、冰碛物及假冰碛岩的资料,提出平均值、偏度、直方图及散点图在鉴别冰川堆积物中有独特作用,也是区分假冰碛岩的有效方法,而其它参数和图件则有多解性.
It is difficult to distinguish tillites from pseudotillites in the light of megascopic features. Parameters of grain-size and characteristics of size-frequency distribution of the Luoquan Formation tillites are reported in this paper. As to the four size-frequency figures,the histogram has a broad area with low percentage, but the characteristic kurtosis(3. 5-5. 5)is prominent with relatively high percentage. The general feature of CM figure is parallel! to the base line of C=M ,and the mean value of C/M is about 20. Probability curve has not only a broad range,but also a low rate of tilt. The general trend on scatter diagrams is near tillite but far apart from other types of deposits.
Through the comparison and synthesis of tillite,till,turbidite,alluvial fan and mudflow deposits, the authors suggest that the graphic mean,skewness,histogram and especially the scatter diagram are the most useful microscopic criteria for both discriminating glacial sediments and distinguishing tillites from other clastic sediments.
出处
《地质科技情报》
CAS
CSCD
北大核心
1991年第3期43-48,共6页
Geological Science and Technology Information
