黄土是一种典型的结构性土，变形和强度与其微观结构密切相关。黄土的矿物组分、宏微观结构、粒度组成均与自身的形成条件和形成过程有着密切的关系。一直被认为是记录第四纪古气候强度变化的重要档案库。深入研究黄土微观结构与地球化学特征对进一步认识黄土独特的工程地质特性及黄土的沉积环境有重要意义。 洛川坡头黄土剖面是黄土高原标准剖面之一，具有较强的黄土典型性和区域对比性，前人利用洛川黄土开展过大量研究。本文以洛川L1黄土为研究对象，结合扫描电子显微镜、能谱仪分析和图像处理等技术，在保证黄土原有结构的前提下，从多尺度微观结构研究的角度出发，在微观上观察黄土内部细节的特点，从宏观上进行规律统计，开展了黄土微观结构的研究。主要内容是测定了洛川L1黄土300微米级厚度中石英及易风化矿物的粒度分布；并从多尺度的角度对洛川L1黄土的微观结构进行了对比分析。研究结果显示：1）在1~3um处，硅酸盐矿物和碳酸盐矿物的粒度分布曲线均有明显峰值出现，该发现可能为进一步开展相互印证的古气候指标研究提供了新思路；2）通过观察发现：黄土中的颗粒薄膜不仅仅由碳酸盐矿物薄膜组成，还包括大量硅酸盐矿物薄膜。作者认为：黄土中颗粒薄膜不完全是化学风化作用的产物，物理风化对黄土中颗粒薄膜的形成也具有重要影响；3）黄土中存在着大量的针片状矿物，这些矿物既包括石英等不易风化的矿物，也包括云母、高岭石等易风化矿物。根据这些大量粒径大于60um小于100um的针片状易风化矿物的存在，初步推断，黄土的粒径分布有可能比前期研究预想的更均匀；4）黄土中不同矿物组分之间存在着极为明显的咬合现象，作者认为：黄土中的一部分小石英是原地风化成壤的产物；5）通过本次的研究，有可能为黄土高分辨率定年研究提供新思路。 以上方法和技术，对认识黄土的微观结构、反演古气候环境，以及评价黄土工程地质和水文地质问题都有着现实的重要意义。

Loess is a typical structural soil. The deformation and strength of loess have a close relationship with its microstructure. The mineral components, the macro and micro structure, as well as the particle size composition of loess are closely associated with its forming conditions. It has been regarded as an important archive to record the changes of the Quaternary paleoclimatic environment. The further research of the microstructure and the geochemical characteristics of loess have a great significance for further understanding of the characteristic of engineering geology and sedimentary environment. The profile of Luochuan loess is one of the standard profile in the loess plateau. A large number of studies have been carried out on Luochuan loess. Taking Luochuan L1 loess as research objects in this paper. By combining Scanning Electron Microscopy (SEM), English Dialect Society (EDS) and image processing technology, this thesis includes two parts: In 300 Micron-thick level, the particle size distribution of quartz and easily weathering minerals in Luochuan L1 loess were measured.From the perspective of multi-scale,the microstructure of Luochuan L1 Loess were analyzed comparatively. Research shows that:(1) The obvious peak of the particle size distribution of silicate minerals and carbonate minerals can be observed in the size fraction of 1~3um. The findings may provide a new idea for confirming each other in the paleoclimatic index research. (2) It is observed that the granular films in loess not only have silicate minerals films but also have numbers of carbonate mineral films. Author thinks that the granular films in loess is not due to chemical weathering completely,physical weathering also has an important effect on the forming of granular films. (3) There are large number of elongated and flaky particles in Luochuan L1 loess,including not easily weathered minerals such as quartz, easily weathered minerals such as kaolinite and mica. A large number of the elongated and flaky particles in the size fraction of 60~100um infers that the particle size distribution of loess may be more uniform than previously thought. (4) Abvious occlusion phenomenon exist in different mineral components in loess. Author suggests that a small part of quartz is the product of local weathering and processes. (5) This study may provide a new idea for the dating scale of high resolution in loess. Methods and technologies above both have practical significance in studying the microstructure of loess, reflecting paleoclimate environment and estimating geological and hydrogeological problems of loess.