【作者】 时连强；

【导师】 李九发；

【作者基本信息】 华东师范大学 ， 自然地理学， 2006， 博士

【摘要】 黄河口以其来水少、来沙多、海洋动力较弱、入海流路改道频繁、海岸淤积延伸快速转为侵蚀后退明显以及对流域环境变化的响应最敏感等为特点，成为海岸带陆海相互作用研究的典型区域。 飞雁滩海滩位于刁口河亚三角洲海岸，1976年5月黄河改道清水沟流路入海后，海岸开始强烈冲刷后退，严重威胁到飞雁滩油田的作业安全和生产建设。 HF孔岩芯取自黄河三角洲北部飞雁滩106站高潮滩，孔深约30m，岩芯按1m间隔采样。样品剖开后，根据需要选取183个样品做了粒度和磁性分析，13个样品做了工程力学性质测定，15个样品做了清水冲刷试验。通过对所得实验结果的综合分析，在建立黄河三角洲飞雁滩高分辨率基本沉积层序的基础上，探讨了沉积物的沉积特性与抗冲能力之间的关系。 1．HF孔岩芯沉积物样品中粉砂含量最高，其次是粘土，砂的含量最低。沉积物以粘土质粉砂、砂质粉砂、粉砂和粉砂质砂为主要，不同类型的沉积物分布在不同的部位。粘土和粉砂含量随深度都呈阶梯状变化，砂含量则是浅部和深部变化较大，中间变化较小。沉积物粒度参数在垂向上的变化也具有明显的规律性，可划分为八个沉积层。典型样品的粒度频率分布曲线特征表明，各样品的粒度频率分布曲线主要以单峰、负偏态、细尾较长为特征，众值基本上位于3～6φ之间。 2．低矫顽力的亚铁磁性矿物主导了HF孔岩芯大部分样品的磁性特征，但反铁磁性物质对部分样品磁性的贡献比较大。亚铁磁性矿物晶粒以较粗的假单畴-多畴颗粒为主，但在14.4～20.4m之间单畴-假单畴颗粒主导了样品的磁性特征。典型样品的热磁曲线揭示出沉积物中的磁性矿物以磁铁矿系列为主。飞雁滩HF孔岩芯的沉积物磁参数变化较大，磁性强弱差异显著，存在明显的垂向差异，自上而下可分为七个层位。由于沉积物粒度大小受水动力条件的制约，因而，沉积物磁性参数的变化主要反映了水动力能量变化。粒度和磁性参数的突变可能是黄河特大洪峰和风暴潮造成的。x_ARM、x_ARM／χ和x_ARM／SIRM可视作细粒级组份含量的代用指标。 3．根据前人研究和黄河三角洲基底层的性质以及飞雁滩HF孔岩芯粒度、磁性特征，推断HF孔的基底沉积层位于21.7～18.3m之间，进而大致建立了HF孔的沉积层序，自下而上可以划分为浅海相（21.7～18.3m）、前三角洲相（18.3～9.8m）和三角洲前缘相（9.8～0.0m）。 4．飞雁滩HF孔沉积物工程特性随着埋深的变化呈有规律的变化，粘土质粉砂与粉砂质细砂的特性有明显差别，并且大部分参数的大小与沉积物中粘土颗粒含量多少有很大关系。更多还原

【Abstract】 The Yellow River delta has become a typical zone for interactional studies between land and ocean, owing to its characteristics such as less runoff, more sediment transport, weak coastal hydrodynamic, frequent change of the ocean outfall channel, and transformation from fast coastal accretion before to obvious coastal erosion now, sensitive response to the environmental change of drainage area, etc.Feiyantan tidal flat is located in the coast of Diaokou River subdelta. Safety of the Feiyantan Oil-field behind the seawalls has been threatened seriously because of the violent coastal erosion since the ocean outfall channel of the Yellow River was changed to the Qingshuigou River in May, 1976.Core HF, about 30m depth, was obtained at intervals of 1m from the high tidal flat of Feiyantan at station 106 on the northern coast of the Yellow Rive Delta. After the samples were cut open, 183 ones were chosen for paticle size and magnetism analysis, 13 ones for basic engineering mechanics measure and 15 ones for erosion experiment in uniform flows. It aims to discuss the relationship between sedimentary characteristic of the sediment and the erosion resistance for samples taken at different depth, based on the fine resolution sedimentary sequence.The main conclusions are as follows:1. In core HF, the silt content is the highest, the clay content is the second and the the sand content is the lowest. Clayey silt, sandy silt, silt and silty sand are the main sediment types and different types of sediment distribute in different depth. The clay content and silt content all change stepwise against depth, whereas the sand content changes within a wide range at the top and deep layers, and within a narrow range at the middle layer. The change of granularity parameters also shows obvious regularity, which can be divided into eight layers. The main propeties of particle size frequency curves of typical samples are single kurtoses, minus skewness, longer thin trail and the mode values are between 3 Φ and 6 Φ.2. The lower （B_）)_cr ferrimagnetic minerals dominate the magnetic properties of most samples in core HF, but the contribution of anti-ferromagnetic minerals cannot be neglected in some samples. Pseudo-single domain （PSD） / multi-domain （MD） in size is the main component, but single domain （SD） / pseudo-single domain in size dominates the magnetic properties of the samples in the depth of 14.4-20.4m. Thermomagnetic curves of the typical samples reveal that magnetite series are the更多还原