东海全新世的下限

ON THE LOWER LIMIT OF HOLOCENE IN THE DONGHAI SEA

一、国内外全新世研究概略全新世是地质历史最新的一页,与人类活动的关系极为密切,因此人们对其研究更为重视。有关全新世地层的划分,普遍采用所谓布列特-色尔南德尔方案,把全新世划分为五个气候期,自老至新为: 亚北极期(或称前北方期):寒冷;北方期:干而温;大西洋期:湿而暖;亚北方期:干而温;亚大西洋期:湿而凉。波斯特(L. V. Post,1944)研究南波罗的海泥炭沼泽的孢粉.

The Lower limit of Holocene in the Donghai Sea(East China Sea)is marked by the following features in sporo-pollen and algal assemblages:(1)the cold-resistant Picea,Abies and Larix are almost absent;Cupressaceae and herb decrease in number obviously,as compared with those of the sporo-pollen and algal assemblages of the Upper Pleistocene,whereas Quercus increases evidently.(2)the freshwater algae(Pediastrum,Zygnema,Concentzicystes and Desmidiaceae)are usually rare,whereas marine diatoms,Hystrichosphaera and Dictyocha and dinoflagellates etc.occur enormously.The changes in the sporo-pollen and algal assemblages near the boundary between the Pleistocene and the Holocene,with an age of about 12000 years,are obvious.On the other hand,the changes in paleogeography,paleoclimate,sedimentary environments and ancient sea level fluctuations are also very evident.