金州湾表层沉积物粒度特征及沉积环境

Grain size characteristics and sedimentary environment of surface sediments in Jinzhou Bay

通过对金州湾海域72个表层沉积物样品进行粒度分析,探讨了金州湾表层沉积物物质组成和粒度参数的分布特征,根据粒度参数特征,利用Q型聚类分析将研究区划分为3组沉积区,结合粒度频率分布曲线、粒度概率累积曲线和C-M图阐述沉积物的粒径组成、沉积动力条件和沉积物的搬运沉积条件。结果表明:研究区沉积物类型为粘土质粉砂、粉砂质砂、砂质粉砂、砂和砂-粉砂-粘土。研究区可划分为3种沉积环境,Ⅰ组沉积环境:沉积物类型以砂质粉砂和粘土质粉砂为主,粒径较小,含部分粗组分颗粒物,分选差,粒度频率分布曲线呈双峰,形成较为封闭静稳的海湾环境;Ⅱ组沉积环境:沉积物类型以粘土质粉砂为主,粒径小、分选较差-差,沉积环境较为复杂,为受潮流和沿岸流作用的沉积环境;Ⅲ组沉积环境:沉积物类型以粉砂质砂和砂为主,粒径较大、分选较差,为受潮流和海流影响的沉积环境。整体上由东向西,沉积物呈现出细-较粗-粗的变化趋势。其原因在于机场人工岛的建设阻挡了潮流和海流的作用,导致东部的I、Ⅱ组沉积环境形成较为封闭的环境;Ⅲ组沉积环境为离岸较远的海洋环境,水动力较强,海洋性特征明显。因此机场人工岛的建设对金州湾海域沉积物的分布产生了显著影响。

Based on the particle size data of 72 surface sediment samples from the Jinzhou Bay sea area,the material composition and the distribution characteristics of particle size parameters are discussed.According to the characteristics of particle size parameters in terms of frequency curve,probability cumulative curve and C-M diagram that illustrate the size composition of sediments and the conditions of sedimentary dynamics,sediment transports and sedimentations,the study area can be divided into 3 sedimentary areas by Q-type cluster analysis.The results show that there are clayey silt,silty sand,sandy silt,sand and sand-silt-clay in the area studied.And thus,3 groups of sedimentary environments can be identified.Group I sedimentary environment is mainly composed of sandy silt and clayey silt,including small particle size and some coarse-component of small size and poorly sorted particles characterizing a frequency curve of double peaks from a relatively closed and stable bay environment.Group II sedimentary environment is mainly composed of clayey silt with small and coarse particle sizes,poor-to-poor sorting that formed in a more complex sedimentary environment due to actions of tidal and coastal currents.Group III sedimentary environment is mainly formed by silty sands and sands with poorly sorted coarser particles as result of tidal currents and ocean currents.As a whole,the sediments show a trend of fine-coarser-coarse changes.The reason is that the artificial island construction for airport has blocked the tidal currents and ocean currents,leading a relatively closed environment in the sedimentary environments of Group I and Group II in the east due to weak hydrodynamics.Therefore,the artificial island construction has a significant impact on the sediment distribution of Jinzhou Bay.