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第四纪研究 1991
APPLICATION OF SCANNING ELECTRON MICROSCOPE TO THE STUDY ON MICROTEXTURES OF LOESS
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Abstract:
Since the 1970s,we have systematically studied the textures on the surface of quartzgrains,features of microtextures and the genesis of calcareous dolls in loess and paleosol usingscanning electron microscope.The results are of important theoretical and practical signifi-cance in discussion of the genesis and natures of pedogenesis and engineering geology andthe effects of environmental geology of loess in China.The microtexture types of loess under SEM depend on the contact relation betweencoarse minerals,features of pores and types and degree of cementation.On the basis of abovementioned features,the microtextures of loess in China may be classified into the following3 texture groups and 6 types:1.Supporting-mosaic texture group existing in the loess of the Late Pleistocene:includ-ing (1) supporting-macropore texture and (2) Mosaic-micropore texture.2.Semi-cementation texture group existing in the loess of the Middle Pleistocene:includ-ing (3) supporting macropore semi-cementation texture and (4) Mosaic-micropore semi-cemen-tation texture.3.Cementation texture group existing in the Early Pleistocene:including (5) Flocculentcementation texture and (6) Coagulum cementation texture.Meanwhile,according to the field features we have preliminarily divided the calcareousdolls of loess into five texture types (i.e.,Homogeneous,Concentric,Cored,Radial and Mor-tar structure) and three genesis types (i.e.,Syngenetic dolls,.Pedogenic dolls and Epigeneticdolls).In addition,this paper has highlighted on the method of studying microtextures of loessunder the Scanning Electron Microscope,e.g.,the preparation of samples,the explanation ofpictures,etc.