摘要
本文在野外考察基础上,通过粒度分析、粘土矿物分析和化学分析,表明塑性泥石流(泥石流新类型)在沉积特征上与常态泥石流(粘性泥石流和稀性泥石流的总称)有明显的区别。细粒含量高(13％以上);SiO_2、Fe_2O_3、Al_2O_3和CaO是沉积物中最主要的化学成分(80％以上);沉积物属于分选“很差型”;土体塑性指数为10.7,属于中塑性上;挠曲构造是该类泥石流典型的沉积构造;剪切应力是塑性泥石流形成的主要动力条件。
This paper mainly discuss the sedimentologic features of plastic debris flow (PDF) (a new type of debris flow discovered recently) and approach its formative condition on the basis of size -analysis, chemical analysis and mechanical analysis. All results identify that fine size content is richer than that of other debris flows, (above 13%), SiO2, Al2O3, Fe2O3 and CaO are the chiefly chemical component (82. 21%). Frequent curve of the sediment in PDF indicate that sediment not only include rich rolling -sediment and leaping -sediment (above 80%), but also a little suspending -sediment, formed at local site and having certain gradding or bedding; Size distributive curve of the sediment show multipeak, clearly tripeak, i.e. - 0. 5-0. 5φ, 2. 0-3. 0φ - 3. 0～-2. 5φ; All size parameters mean that the sediment belong to 'bad gradding type'. Earth of the debris flow is of mediplastic, whose plastic index is 10. 7; Flexure structure is typical sedimentologic structure in PDF, and according to this we think that shera stress must have been the remarkably dynamical condition for PDF to develope.
出处
《沉积学报》
CAS
CSCD
北大核心
1993年第4期37-41,共5页
Acta Sedimentologica Sinica
基金
国家教委博士点基金课题
