中国黄土高原古土壤中粘粒移动问题探讨

黄土高原黄土沉积剖面中常出现若干古土壤层,该层往往是碳酸钙被淋失而粘粒含量特高的土壤发生层。因而对于该层粘粒来源引起了很大的争论。残积粘化论者认为黄土层中古土壤中的粘粒以伊利石为主,且为钙镁饱和,亲水能力差,不易发生机械淋溶现象。但是不论现代或古代土壤发生层中的确发生粘粒局部位移和富聚等现象,如结耕体外常见有发亮胶膜的出现和在薄片观察中可见光性定向粘粒和螺纹状聚集等现象。本文除确认上述现象存在外,

CLAY MOVEMENT IN PALEOSOLS OF THE LOESS PLATEAU IN CHINA

There are several Paleosols which contain a high proportion of clay with the leaching out of lime carbonates in loss profile. The origins of the clays have caused great argument. Researchers who maintain the point of view of residual argillification have thought that the clays in the paleosols are dominated by illites with Iime-magnesia saturation and have very weak hydrophility and mechanical eluviation. But, the phenomena of clay partial translocation and accumulation do exist in either recent soils or paleosols. For instance, the shining cutan outside the ped or optical orientation clay particles and whorl-shaped aggregates in the thin section investigations or both of them were observed. This paper, besides the affirmation to the existence of above phenomena, indiGates that the causes of the phenomena are different from those of phenimena which result from the mechanical eluviation and illuviation in common soil profile in that they were caused by intensive biological effect, espectially by bio decay and minerslization and mineral feedback and "biosynthesis" (biogenetic) of the clay minerals in two to one crystalline structure on the surface of mollisols in which herbage had grown lushly at the early stage of the soil formation, and "mitcro-ice wedge like" actions particually the later even leads to the formation of star-clove of garlic-shaped soil masses with smooth and shining surface within the transitional areas between claying hirizons and C horizons.