【摘要】 渤海湾西岸出露或埋藏了多道贝壳堤,通过地质调查发现:贝壳堤的平面分布结构是沿着(或随着)渤海湾海岸由老至新(从岸—海)与海岸呈大致平行排列。贝壳堤的划分方案有两种,一种是从新至老,另一种是从老至新,本文采取后一种划分方法:即第Ⅰ道(老)—第Ⅵ道(新)贝壳堤。本文对每道贝壳堤的物质(岩性特征)组成与堆积特征进行了描述(图2～图7);对贝壳堤的几何形态特征进行了数理统计(表2);对贝壳堤形成的年代特征进行了对比分析(表3);对贝壳堤的生物组合特征等资料进行了归纳和整理;对贝壳堤的分道方案进行了对比分析(表1),揭示了贝壳堤的赋存状态、形成的年代及第Ⅰ道—第Ⅵ道贝壳堤所处的潮位变化(图8)。以形成贝壳堤这一独特的地质载体为基础,试图从渤海湾宏观整体的角度分析并揭示贝壳堤的成因机制(表4,图9),笔者认为广义的渤海湾是内陆的半泻湖(海),也可以视为局部海:山东庙岛列岛—辽东半岛构成了渤海的障壁海岸,在障壁海岸这样的自然地理和地貌条件下,通过大量的资料综合分析认为只有障壁海岸才是形成"科珀河型三角洲与喙状三角洲"的必然条件,而"科珀河型三角洲与喙状三角洲类型"等是形成障壁砂坝(障壁岛,障壁滩)—贝壳堤的或然条件,这就是贝壳堤成因的主要机制。更多还原

【Abstract】 There are 6 Barrier Sand-bars are outcropped or buried on the west coast of Bohai Bay.Based on the geological survey,it is found that the plane distribution features texture of the Barrier Sand-bars,which are from the old to the new are roughly parallel with the coast along the west coast of Bohai Bay(from the coast to the sea).The distribution of the Barrier Sand-bars can be divided into two kinds,one is from the new to the old,and the other one is from the old to the new.In this paper,the division of the Barrier Sand-bars fromⅠ(old) to Ⅵ(new) by using the latter one.Through the description of the material composition and the accumulation characteristics to each barrier sand-bar(figure.2 to figure.7),conducting the mathematical statistics for the geometrical morphological features(table 2),comparing analysis the formation age features and the division scheme(table 3),summing up the biological assemblages(table 1),the result reveal the occurrence,formation age and the tidal level change of the Barrier Sand-bars fromⅠto Ⅵ(figure.8).In the basis of the Barrier Sand-bars as a particular geological carrier,the author try to analysis and reveal the genetic mechanism in a macroscopic view,and consider that the generalized Bohai Sea is inland semi-lagoon or local sea in reality.(table.4 figure.9) Shangdong Miaodao Island and Liaodong Peninsula constitute barrier coast for Bohai Sea.After comparing analysis to massive data,the barrier coast is an only essential condition to form kebohe delta and beaked delta,both of which may be a possibility condition to form barrier bars(barrier island,barrier beach) or shell ridges.This result is just main genetic mechanism for the shell ridges.更多还原