最大海侵时期古渤海潮流沉积动力环境特征及其与现今对比  

TIDAL DYNAMICS OF ANCIENT BOHAI SEA AT THE TRANSGRESSION MAXIMUM AND ITS COMPARISON WITH THE PRESENT

作　　者：季有俊[1] 杨作升[1] 王厚杰[1] 毕乃双[1] 芦静[2] 

机构地区：[1]中国海洋大学海底科学与探测技术教育部重点实验室,青岛266100 [2]国家海洋局第一海洋研究所海洋环境科学和数值模拟国家海洋局重点实验室,青岛266061

出　　处：《海洋地质与第四纪地质》2011年第3期31-39,共9页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(40876019)

摘　　要：全新世以来最大海侵时期(7kaBP)中国东部海的海平面达到最大,黄河三角洲此时期并未形成,整个古渤海西部轮廓较开阔。依据前人浅地层剖面和岩心测年的研究,大体恢复了中国东部海的古岸线和古水深,运用三维水动力悬沙数学模型(ECOMSED)对最大海侵时期和现今两个时期渤海的潮流沉积动力过程进行了数值模拟研究,结果显示,由于古渤海较现今水深大、区域宽广,加之传入古渤海的潮波较现在弱,古渤海的潮流较现在弱很多,尤其是渤海西部黄河入海区域。在这种较弱的潮流动力环境下,黄河入海泥沙更容易沉降,更容易快速堆积并向外海推进,更有利于黄河物质在近岸堆积和形成黄河三角洲。由于古渤海水动力较弱,黄河泥沙输出渤海的泥沙较现在的比例要少。古今渤海中部和渤海海峡东部潮流都较弱,细颗粒泥沙易沉降,沉积厚度较大,而辽东湾内整体潮流动力较强,细颗粒泥沙不易沉降,是导致辽东湾内底质颗粒相对较粗的主要原因之一。The sea level reached its maximum off east China at 7 000 aBP,and the Yellow River delta was not formed then.The western part of the ancient Bohai Sea was very wide at that time.Based on the previous studies of seismic profiles and coring data,paleocoastlines and paleotopography were roughly recovered in this paper.A three dimensional numerical model based on the hydrodynamic sediment model of ECOMSED was established to simulate the tidal process in the Bohai Sea during the transgression maximum and the present.The results show that the tidal currents of the ancient Bohai Sea during the period of the maximum transgression（7 kaBP） were much weaker than those in the present time,especially in the west part of the ancient Bohai Sea,as a result of greater water depth,wider coast zone and weaker tidal waves from the Yellow Sea.Under such a weak tidal hydrodynamic environment,the sediment of the ancient Yellow River easily discharged into the sea.The rapid sedimentation around the river mouth was beneficial to the formation of the Yellow River delta.In addition,less sediments were dispersed from the Bohai Sea.There were two places in the central Bohai Sea and eastern Bohai Strait respectively with very weak tidal currents.They became active depositional pools for thicker sediments to accumulate.The tidal hydrodynamic was stronger in the Liaodong Bay,marked by the coarser surface sediments.

关 键 词：最大海侵时期 潮流沉积 数值模拟 古渤海 

分 类 号：P736.2[天文地球—海洋地质]