摘要:
根据2000年7~9月黄河三角洲滨海区表层沉积物的分析结果,运用F lem ing的三角图式对沉积环境进行划分,并在此基础上结合沉积物结构、地形和水动力条件,探讨了沉积物的分布规律及其作用机制。结果表明:研究区域可划分为废弃三角洲滨海区、现行河口区和莱州湾滨海区三个沉积环境。对于废弃三角洲沉积区,在早期废弃的湾湾沟海区风浪作用为主,沉积物普遍较粗,抗冲能力较强;废弃不久的飞雁滩海区在波流联合作用下,沉积物粒径由岸向海变细,大致在-5~-6m水深处存在一明显的界限,该水深以浅砂含量较高;而该水深以深以粉砂和粘土为主,砂含量较低。现行河口区,由于沙嘴前方强潮流带的作用,沉积物粒径由岸向海表现为粗—细—粗的演变趋势。在莱州湾海区,由于潮流场的影响,以广利河河口为界,以北粒径较细,而以南则较粗。
Abstract:
Based on the measured data of bottom sediment samples, combined with sediment texture, topography and hydrodynamics, a new triangular diagram advanced by Fleming is applied to reveal the sedimentary environments and their hydrodynamic processes. The results indicate that the nearshore zone of the Yellow River delta is divided into three sedimentary environments: the area near abandoned delta, estuarine area, and Laizhou Bay. In nearshore zone of the abandoned delta, there are two parts, Wanwan'gou and Feiyantan, which were abandoned in 1953 and 1976, respectively. Due to long-term scouring of wind wave, the grain composition of the majority bottom sediment near Wanwan'gou is coarse showing the strong erosion- resisting characteristics. For Feiyantan, because of combined effect of wave and tidal current, there is a large percentage of the sand at the underwater slope, which is shallower than -5~-6 m, however, slit and clay predominate at the underwater slope, which is deeper than -5~-6m. For the area near the current estuarine, the grain size has a changing tendency of coarse-fine-coarse that results from the effect of strong tidal current zone in front of sand spit. For the area near Laizhou Bay, because of the influence of tidal current field, grain size of the bottom sediment particles is coarser in the area south of Guangli River estuary than the area north of that.
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