【摘要】 盐城上冈地区全新世期间处于泥砂质潮滩环境。根据有孔虫组合分析 ,这套近岸潮滩沉积代表潮下带 -潮间带 -潮上带的一次大海退过程。本文分析了上冈村砖瓦厂采泥坑东侧 SGE柱状剖面全新统的颗石藻化石 ,结果发现这套沉积物仅仅含 Gephyrocapsa oceanica单一属种 ,而且丰度较低。但这个种在剖面上的丰度分布显示三分性 :即自下至上为贫乏或缺失间隔、较常见间隔和常见间隔 ,基本上对应于潮下带、潮间带和潮上带。一般情况下 ,潮坪区由海向陆水动力由强至弱 ,各相带的水动力条件不同 ,其沉积特征各异。颗石藻胳架十分细微 ,在海水中往往以悬浮形式搬运 ,并在水动力较弱时停积。所以 ,水动力是 G.oceanica分布的直接控制因素更多还原

【Abstract】 According to the analyses of foraminifera assemblages, Shanggang area was situated in the tidal flat and was under the process of regression from subtidal zone to supratidal zone throughout Holocene. The SGE column section with a total of 420cm in length located about 100m in the east of Shanggang village mainly consists of muds, silts and fine sands. The results of 48 samples studied for calcareous nannofossils from this column show that Gephyrocapsa oceanica Kamptner (1943) is a unique species and very low in abundance. On the basis of the abundance variation of G.oceanica this section can be subdivided into three divisions from bottom to top. Division 1 The interval is 0—140cm. G. oceanica rarely occurred in some samples and completely missed in most samples. The sediments possessing ripple lamination, parallel lamination and cross stratification include fine sands, medium fine silts, as well as muds, which were formed under the environment of the subtidal zone with higher energy. Division 2 There is an interval from 140cm to 332cm, where G.oceanica is common except sandy samples. The sediments are composed of sand and mud and increased in mud content toward upper part. The sedimentary structures mainly in clude lenticular stratification and interlayered stratification. This division, therefore, suggests environments from the lower flat to upper flat with a decrease in the energy of seawater. Division 3 This interval is the 322—420cm interval with an increase of large quantities of mud content. G.oceanica here is more common than that of division 2, which may be related with the decrease in the water energy under the conditions of a high flat supratidal zone. To sum up, it seems that the distribution pattern of G.oceanica in tidal flat area is directly controlled by hydraulics of seawater.更多还原