南日岛东部海底地形地貌及沉积特征

CHARACTERISTICS OF SUBMARINE TOPOGRAPHY AND SEDIMENTS OF THE EAST NANRI ISLAND

利用测得的高精度多波束数据,绘制海底三维地形图及海底深度等值线图,对海底地形地貌特征进行了分析。A区海底地形总体上呈NW—SE向延伸的沟—脊相间的条带状分布;B区南部海底地势较平坦,中北部海域地形主要受到岛屿和礁石影响。对研究区海域沉积物进行采集,采用筛析法和激光粒度仪相结合的方法对样品进行分析,并用谢帕德分类图解法将沉积物分为10种类型,绘制研究区表层沉积物类型分布图。根据实测的表层沉积物粒度资料,对沉积物平均粒径、分选系数、偏度及峰态等4种粒度参数进行计算,并绘制粒度参数的等值线图,对各参数的平面分布特征进行分析。测区范围内没有发现严重影响风力发电设施建设的灾害性地质因素存在。

The three-dimensional topographic map and bathymetric map of the seafloor have been made for the North Nanri Island with the high-resolution multi-beam data. The seafloor topography of the Area A extends from NW to SE characterized by alternative trenches and ridges, while the submarine topography of the Area B is rather flat, and the landform in the middle and northern corner is influ- enced by islands and reefs. We collect the sediment samples from the study area, and analyze these samples by sieving methods and laser particle size analyzer for grain size distribution. The sediments are divided into 10 varieties according to the Shepard classification. A subsurface sediment distribution map of the study area is made with the data. Grain size parameters, i.e. the mean grain size, sorting coefficient, skewness and kurtosis are calculated, and contour maps are made for each parameter. There have found no geologic hazard factors that would influence the wind power facilities in the study area.