黑石岛附近海域地形地貌及表层沉积物分布特征分析

黑石岛附近海域位于山东威海黑泥湾东部，沉积环境复杂多变，多种因素控制表层沉积物分布，形成多种发育演化模式。利用单波束测深系统、浅地层剖面系统、表层沉积物取样、海流观测和实验室沉积物粒度测试、资料综合解释等方法，于2021年9—11月对研究海域开展综合地质环境调查。通过调查数据分析研究区水深地形特征、浅地层结构特征以及表层沉积物分布特征，并从多个角度揭示该海域沉积物分布特征的控制因素和成因。研究发现：目标海域水深介于3～24 m，平均水深约14 m，西部浅、东部深，存在陡坡，随着水深的增加坡度逐渐变缓，地貌类型主要以水下侵蚀岸坡为主；海底浅地层声学反射界面清晰，可全局跟踪，淤积厚度为0.5～2 m，沉积层厚度东西存在差异但相对稳定；表层沉积物类型多样，大致围绕黑石岛呈环带状分布，离岛方向上依次为粉砂、砾石、泥质砾；自西向东表层沉积物粒度逐渐减小，分选性变好。研究区表层沉积物分布受区域地形地貌和水动力条件的共同影响。

The characteristics of topography and surface sediment distributionnear Heishi Island,Shandong Peninsula

The sea areas near Heishi Island are located in the east of Heini Bay, Weihai, Shandong Peninsular, East China. The sedimentary environment is complex and variable, and many factors control the distribution of surface sediments, forming a variety of developmental and evolutionary patterns. A comprehensive geological environment survey of the study area was carried out in Sep.–Nov., 2021 by using acoustic detection, surface sediment sampling, ocean current observation, laboratory sediment grain size testing, and comprehensive interpretation of data, based on which the characteristics of water depth topography, sub-bottom profile structure, and surface sediment distribution in the study area were analyzed and the controlling factors and causes of sediment distribution in the area were revealed from multiple perspectives. Results show that the water depth of the target area was between 3 m and 24 m, on average of about 14 m, shallower in the west and deeper in the east in a steep slope. With the increase of water depth, the slope gradually decreased, and the main landform type was underwater erosion bank slope. The acoustic reflection interface of seabed sub-bottom profile was clear and co be tracked globally. The siltation thickness was 0.5–2 m, and the thickness of sediment layer varied from east to west but relatively stable. The types of surface sediments varied, forming zones around the island, including silty sand, gravel, and muddy gravel away from the island. From west to east, the grain size of surface sediments decreased gradually and the sorting became better. It is concluded that the distribution of surface sediments in the study area is affected by regional topography and hydrodynamic conditions.