【摘要】 <正>北仑港南侧为一面积约100平方公里的海岸平原.它北临金圹水道,东、西、南三面被中生代火山岩组成的低山丘陵所环抱.平原面积虽然不大,但根据一系列钻孔揭露,第四纪松散沉积物的厚度仍可达100米左右.笔者检验了数十个钻孔资料,并对A₈孔、穿山西₁孔等进行了系统的取样,在实验室内作了粒度分析和微体古生物鉴定.根据岩相及丰富的有孔虫化石群,划分出三个海相层.本文介绍了上述成果,并就三个海相层的形成时代、它们与我国其它沿海地区的对比,以及有关的古地理意义等问题作了探讨.更多还原

【Abstract】 Based on examination of core data of tens drilling holes, systematic size analyses and micropaleontological analyses of the two drilling cores, three marine strata are found in the Quaternary deposits of the coast plain in the south of the Beilun Harbour area. Preliminary conclusions are as follows.1. The presence of the three marine strata reflects that three marine transgressions have affected the Beilun Harbour area. They probably occurred in about 100000 y.B.P., 36000y.B.P. and 10000y.B.P. respectively.2. Development of the marine strata in the area is consistent with its adjacent areas such as the Wen-Huang Plain, the Cibei Plain in Zhejiang and the Changjiang River Delta; besids, it can be compared with the North Jiangsu Plain and the coast area along Bohai Bay. It shows that the. Beilun Harbour area has been subsiding since the Late Pleistocene about 100000y.B.P.3. The characteristics of the present Jingtang channel perhaps have been formed at the beginning of the Late Pleistocene. But the influence of the Taiwan Warm Current at that time probably was stronger than present, and the temperature of the sea water at that time also was-higher than nowadays.4. The development of the Zhoushan Islands is related with the transgressions and appearances of all channels in the Zhoushan area such as the Jingtang Channel, etc. The Zhoushan area were divorced from the China mainland by the three transgressions in the last 100000y., then the Zhoushan Islands was formed. Contrarily, the regressions between transgressions have enabled the Zhoushan Islands to be linked with the mainland again.更多还原