中文摘要：

利用不同年份的水深地形资料进行冲淤计算,结合实测水文泥沙、现场岸滩沉积地貌观察、新老海堤分布位置及以往浅地层探测和考古等资料综合分析发现,岸滩地貌形态从大约距今7 000 a前的一个古基岩港湾经受细颗粒泥沙长期不断地充填、淤积转化为近乎平直的岸段.在自然和人类活动的共同作用下,近370 a来海岸线以5.3 m/a的速度向海推移,潮滩以0.25 cm/a的速率沉积.近40余年来水下岸坡平均冲淤速率为-3.8～2.4 cm/a,横向冲淤调整有类似砂质海岸剖面塑造的特性,泥沙经受了在横向剖面“上部微淤、下部微冲”和纵向总体“东侧微冲、中西部微淤”的交替重复调整过程,目前朝着“上部微淤、下部微冲”的均衡剖面调整方向发展.

英文摘要：

It is shown that the coastal configuration has been changed into the nearly straight coast from a rocky ancient bay, about 7 000 a B. P. , which is filled with fine grain-size sediments for a long term, comprehensively analyzed with the data on comparing the bathyorography in different years and calculating sediment erosion and accretion on the subaqueous shore slope area, combining among the observed tidal current, suspended sediment, coastal sedimentological geomorphology in the field and the distribution in the new and old sea dykes, the previous sub-bottom profiling and archaeological results, etc. The coastline is seawards advanced at the speed of 5.3 m/a, under the action both the nature and human activity, and the tidal flat is deposited at the speed rate of 0.25 cm/a in the recent 370 a. The average erosion and deposition rate ranged from -3.8 to 2.4 cm/a on the subaqueous shore slope area over more than 40 a. The erosional depositional processes are similar nearly to the constructive characteristics of coastal sandy profile. Sediments repeatedly underwent the process in the alternate adjustment of ＂the slow accretion in the upper part and slight erosion in the lower part＂ on the onshore-offshore profile and did on the whole ＂the slight erosion in the eastern end as well as slight accretion＂ both in the middle of and in the western end of the alongshore direction. This slope area is developed at present towards adjusting an equilibrium profile in the direction of ＂slow accretion in the upper part and slight erosion in the lower part＂.