辽东湾觉华岛附近海域海底地形地貌及沉积物分布特征分析

Analysis of the characteristics of submarine topography and distribution of sediments near Juehua Island,Liaodong Bay

为对辽东湾觉华岛附近海域海底工程地质环境进行系统评估,利用高分辨海底声学探测设备获取调查海区的精密水深地形及浅地层剖面数据,利用筛析法、激光粒度仪实验法确定表层沉积物类型及粒度参数特征,综合分析了研究区海底地形地貌及沉积物分布特征。研究发现,目标海域测量水深介于4~22 m之间,平均水深15 m左右,海底地形平坦,整体表现为平缓的近岸缓坡,地貌以近岸粉砂淤泥质浅滩地貌为主,局部发育微型海底沙波;海底浅地层第一声学反射界面清楚连续,可全区追踪,穿透深度0.5~5 m不等,沉积物厚度相对稳定;表层沉积物中值粒径普遍较小,沉积物类型东区以粉砂和砂质粉砂为主,西区以砂质粉砂为主;表层沉积物组分和粒度参数的空间变化规律较为复杂,分析认为其主要受到沉积物物源以及辽东湾内往复流、沿岸流的影响。

To evaluate the engineering geological environment of the seafloor near Juehua Island in Liaodong Bay,high-resolution acoustic equipment was used to obtain the precise topographic data of the investigated sea area,and the sediment types and grain size parameters were analyzed by the sieve and laser particle size analysis methods.The topographic data and sedimentary characteristics of the study area were obtained through comprehensive analysis.Results showed that the measured water depth of the study area is between 4 and 22 m,with an average water depth of approximately 15 m.The topography of the seafloor is generally flat and a gentle nearshore slope that is dominated by the nearshore silty muddy shoal landform.Moreover,the micro seabed sand waves are locally developed.The first acoustic reflection interface of the shallow seabed is clear and continuous that can be traced in the entire area.The penetration depth is approximately 0.5~5 m,and the sediment thickness is relatively stable.The average grain size of the surface sediments in the study area is generally small.The sediment types in the east area are mainly silt and sandy silt,whereas those in the west area are mainly sandy silt.Under the influence of sedimen-tary provenance and reciprocating and coastal currents in Liaodong Bay,the spatial variation rules of the compo-nents and grain size parameters are complex.