潮滩沉积记录正演模拟初探  

DETERMINATION OF PRESERVATION POTENTIAL IN TIDAL FLAT SEDIMENTARY RECORDS:A FORWARD MODELING APPROACH

作　　者：高抒[1] 

机构地区：[1]南京大学海岸与海岛开发教育部重点实验室,南京210093

出　　处：《第四纪研究》2007年第5期750-755,共6页Quaternary Sciences

基　　金：国家自然科学基金重点项目(批准号:40231010);国家科学技术部基础研究规划前期研究专项项目(批准号:2006CB708410);江苏省基础研究计划(自然科学基金)前期预研项目(批准号:BK2005211)资助

摘　　要：以江苏中部海岸潮滩沉积为原型,提出了获取潮滩沉积记录中沉积层保存潜力信息的正演模拟方法。模拟结果显示,在沉积物供应恒定的条件下,随着潮滩的不断淤长,岸线淤进速率逐渐减小,潮滩滩面的沉积速率逐渐降低,而潮滩层序中的泥质沉积的厚度向海逐渐增厚。沉积层保存潜力的计算结果显示,潮滩上保存潜力在高潮位附近和潮下带的较低部位为最高,可达80%以上,潮间带下部存在着低值区,保存潜力低于20%,与前人在潮间带进行的现场观测结果相近。对研究方法经进一步细化(如考虑滩面坡度和粒度分布变化、波浪和风暴潮作用、潮沟摆动等因素),并与反演方法相结合,可望更好地解释沉积记录中的环境演化信息。A forward modeling method to obtain information on sediment preservation potential in tidal flat sequences is proposed and an example from the middle Jiangsu coast is provided to illustrate its application. The model output shows that under the condition of constant sediment supply the shoreline progradation is associated with a decreasing prograding rate, a decreasing sediment accumulation rate, and an increasing thickness of mud layer that represents the upper part of the intertidal flat sequence. Calculations for the preservation potential of sediment layers demonstrate that the potential is the highest near the high water level or in the lower parts of the sub-tidal zone, with a maximum of more than 80% ; it is the lowest over the lower part of the inter-tidal zone, with a minimum below 20%. These results are consistent with the observations made by other researchers. The model may be further improved by taking into account the effects of variability of bed slope and sediment distributions, hydrodynamic forces of waves and storms, and tidal creek migration. In combination with inverse methods, the forward modeling method may be beneficial to a better interpretation of sedimentary records.

关 键 词：潮滩沉积 层序保存潜力 正演模拟 全新世 江苏海岸 

分 类 号：P736.21[天文地球—海洋地质]