| Identification, statistics and analysis of the living and necro (taphonomic) foraminifera assemblages of 110 surficial sediment samples, taking from the various subenvironments on subbottom of the intertidal zone and shallow sea, west Bohai Bay, have been systematically carried out in this study. Principal results of this thesis include:(1) Modern foraminifera assemblages of the surficial sediments in the intertidal zone and shallow sea area;(2) Distributions of their dominant species and common species, the indication of modern foraminifera assemblages for geoenvironment and sea level;(3) Elevation/depth influence (ie. the sampling positions, changing from the upper tidal flat to the shallow sea, each of which occupies an exclusive and definite elevation/depth relative to the msl, mean sea level) for the foraminifera composition;(4) Grain size and modern sedimentation rate influence for the foraminifera composition.The major living and dead (buried) dominant species in the intertidal zone and shallow sea, west Bohai Bay, consist of Ammonia beccarii vars., Ammonia limbatobeccarii, Protelphidium tuberculatum, Ammoboculites sp., Elphidium simplex, Pseudogyroidina sinensis, Quinqueloculina akneriana rotunda, Cribrononion porisuturalis, Ammonia granuloumbilica and so on. The common species are composed of Elphidium magellanicum, Elphidium advenum, Cribrononion subincertum and Ammonia maruhasii.The distribution characteristics and main-composition-analysis indicate that foraminifera in the studying area is influenced by a number of subenvironments including neritic sea, intertidal zone, salt marsh near high tides and washland near estuary. Nevertheless, the other subenvironments such as channels off estuary-sluice and tidal channels are obviously less important.By using the cluster-analysis for the dominant species, the modern foraminifera assemblages have been separated into 5 groups and 7 subgroups. Distribution of each group almost parallels the shoreline and corresponds to the various subenvironments from the intertidal zone to shallow sea, respectively.8 selected dominant species indicate that depth (elevation) is a major factor controlling the foraminifera vertical distributions. Detailed discussions include quantitative relationships of the vertical distributions of different genera and/or species with geoenvironments and sea level changes. Sensitivity and precision indices, indicating geoenvironmental and sea level changes, are determined by the vertical distributions of certain single species and their assemblages, in which C. porisuturalis and E. simplex and their Assemblages I, II and IIIa are much more precisely.Also, the environmental factors influencing foraminifera composition have been discussed in this thesis. Comprehensive analyses on the different genera, spices and their different assemblages indicate that, except Protelphidium tuberculatum, grain sizes of the subbottom sediments do not give obvious influences to the foraminifera distribution. Amount of individuals negatively correlates with the vertical accretion of sediments. Area with high modern sedimentation rate has a less amount of individuals while the amount increases when the rate decreases.Based on the classification principle of Marine-Influence-Distribution Index (Ic), regional classification has been established as 0.5 for the lowermost limit determining the terrestrial influence and 0.3 for the uppermost marine influence.As the second portion of this thesis, five case-studies have revealed profound information of the Holocene geoenvironmental and sea level changes from the strata recorded by foraminifera.Based the aforementioned results and discussions, 5 cores, drilling in the intertidal zone and shallow sea, have been thoroughly analyzed for their foraminifera composition. As a result, a local Holocene relative sea level curve has been reconstructed revealing that a rapid-rising period in 7500~6200 cal BP and ensuing slow-rising period. Sea level fluctuations have also been found during the second period without any stand obviously higher than the present level. As a proper paradigm, this approaching effort shows various changes in the modern geoenvironments as the Holocene strata as well by foraminifera study.
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