辽东湾东部砂质区沉积物粒度特征及其物源指示意义

GRAIN SIZE CHARACTERISTICS OF THE CORE SEDIMENTS IN THE EASTERN LIAODONG BAY AND IMPLICATIONS FOR DEPOSITIONAL ENVIRONMENT

对取自辽东湾东部砂质区的4个柱状样沉积物进行了粒度分析，对比了其粒度特征。结果表明，辽东湾潮流沙脊区北侧LDC47孔沉积物中跃移组分含量在70％左右，由两条直线组成，反映了该孔沉积物受到两个不同方向和速度的涨、落潮的往复双向流所控制，具有潮流沙脊特征，该孔沉积物主要来自老铁山水道。LDC30孔沉积物上部（0～2．10m）跃移组分由一条直线构成，含量小于40％；下部（3．0～2．10m）沉积物跃移组分仍由单一直线组成，且含量小于5％，该孔上部沉积物可能为高水位体系域下的河口沉积，下部细颗粒沉积物可能为滨海湖沼或潮坪沉积。LDC71和LDC82孔沉积物上细下粗，跃移组分小于10％，由一直线组成，悬浮组分远大于跃移组分，可能为高水位体系域下前三角洲沉积。上述3个钻孔属近岸砂质沉积，其沉积物可能来源于周边河流的输沙以及沿岸基岩的侵蚀。

Four cores of sediment taken from the Eastern Liaodong Bay were analyzed for grain sizes. The results indicate that the saltation component of the Core LDC47 sediments on the north of the tidal sand ridge is as high as 70 %, which is composed of two straight lines in the probability cumulative frequency di- agram. It means that the sediments of Core LDC47 were formed under a to-and-fro current and indicates an origin of tidal sand ridge. It is deduced that these sediments are mainly from the Laotieshan Channel. However, the saltation component of the upper part （0~2.10 m） of the Core LDC30 is less than 40~, showing as a straight line in the probability cumulative frequency diagram, as the lower part shows no difference with the upper. The saltation component in the lower part is even much lower. It suggests that the upper part of Core LDC30 was probably formed in a pro-delta environment of the highstand system tract, whereas the lower part of the Core LDC30 was deposited in a wetland or tidal flat environment. The upper part of the Core LDC71 and LDC82 are thin with high suspension component and become coarser downwards. The sediments of the Core LDC30, LDCT1 and LDC82 are all belonging to coastal sands pos- sibly derived from the rivers nearby and coastal bed rock erosion.