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在滹沱河平原段180公里范围内,选取上、中、下三个河段。对各段的主河道相、心滩相、边滩相及天然堤相分别进行了沉积构造、粒度结构、轻重矿物和石英表面结构的分析研究。各亚相垂向沉积层序是河流洪——枯水期水动力变化的产物。例如:洪水期心滩剖面自下而上层理表现为:滞留砂砾层中的低角度斜层理(5°～10°),高流态的平行层理或大型板状斜层理,大型槽状斜层理;随着水流的减弱,相继出现小型槽状斜层理及砂波交错层理、水平层理.心滩相整个沉积厚度为1.0米左右。边滩相剖面中层理表现为:洪水期由河床侧向运移而形成的滞留砂砾层中的低角度斜层理,大型槽状斜层理或多丛系大型交错层理,随着水流减弱,层理为小型槽状或小型板状,砂波交错层理及水平层理。边滩相的沉积厚度大于2.0米。粒度分析能反映沉积物沉积时的水动力条件。轻重矿物含量的组合分析效果较好,其中角闪石、石英、长石百分含量可作为划分本河流亚相的重要依据。通过扫描电子显微镜,研究各亚相石英颗粒表面结构的组合特征,可作为沉积环境分析的辅助标志。
Within the range of 180 km from the Hutuo River plain, three upper, middle and lower reachs are selected. The sedimentary structure, grain size structure, light and heavy minerals and the quartz surface structure of the main channel facies, heart facies facies, marginal facies and natural dike facies in each section were analyzed. The vertical sedimentary sequence of each subfacies is the product of hydrodynamic changes during the flood-dry season. For example, the bottom-up strata of flood and heart-sand sections show low-angle bedding (5 ° -10 °) in stagnant gravel, parallel bedding or large slab bedding in high-flow regimes, As the water flow weakened, a series of small trough oblique bedding and sandwiched alternating bedding and horizontal bedding were formed, and the whole sedimentary thickness of heart and beach facies was about 1.0 m. The stratification in the marginal section shows the low-angle bedding, the large-scale bedding or the multi-bedding large-scale interlacing stratification in the retained gravel formed by the lateral migration of the riverbed during the flood period. With the weakening of the water flow , The stratum is small trough or small plate, sandwave cross bedding and horizontal bedding. Sediment facies sediment thickness greater than 2.0 meters. Particle size analysis can reflect the hydrodynamic conditions of sediment deposition. The combined analysis of light and heavy mineral content is better, in which amphibole, quartz and feldspar percentage content can be used as an important basis for the division of the river subfacies. The scanning electron microscope (SEM) was used to study the features of the surface structure of each sub-phase quartz particle, which can be used as a secondary marker for the analysis of sedimentary environment.