山东半岛东北岸发育有许多大型海积地貌体,其中尤以龙口屺岛连岛沙坝、烟台芝罘岛连岛沙坝和荣成石岛湾口沙坝规模最大,形态最典型。这三个形成于不同自然地理条件下的沙坝之间,既有成因、沉积结构、泥沙来源等方面的显着差异性,又有地貌与沉积方面的的可比性。对这些差异性、可比性的深入分析表明,全新世中期以来短时间尺度、小幅度的相对海面变化,对海积地貌发育有着深刻的控制作用。这种控制作用包括海面升降引起的海岸横剖面调整和入海河流河床纵剖面调整,进而对沿岸纵向泥沙流强度和沙坝发育产生深刻影响。

Based on field work, dating,mapping, historical literature and predecessors' work, this paper has discussed the influence of the middle and later Holocene relative sealevel change on the coastal geomorphic evolution along the northeastern Shandong peninsula which stretches from Longkou to Shidao.Along the northeastern Shandong Peninsula, many large sized coastal deposition geomorphic bodies were developed, among which the Qimudao tombolo in Longkou city, Zhifudao tombolo in Yantai city and Shidao bay mouth barrier in Rongcheng city are the biggest in size and most typical in form.Among the three barriers above, which were formed in differeent physical geographic and geologic settings, there is not only remarkable difference in genetic type, barrier platform and sediment resource, but also difference in landfrom and deposition features.According to the analysis on the difference above, it is concluded that the coastal deposition geomorphic evolution has been deeply influenced by the middle and later Holocene relative sealevel change.The influencing mechanism is that the relative sealevel change results in the adjusting of the tranverse shore profile and longitudinal river-bed profile, then influences the intensity of beach drift and barrier evolution.Since the middle Holocene, there are five relativel change phases which include a static phase (6000～4000aBP), two rising phases (4000～2300aBP,1500～600aBP)and two falling phases(2300～1500aBP,600aBP～present).For the two rising phases, the average rising rates are 2.35mm/yr and 2.22mm/yr,which approach the low limit of the estimated relative sealevel rising rate during 1990～2100 A.D..Based on the results of this paper, the future global sealevel rise will influence the the coastal geomorphic evolution along the rock mountain coast such as the northeastern Shandong peninsula.