摘要
本文通过生物、粒度、重矿物、微量元素和^(14)C测年等分析,研究上更新统上段暗绿色硬土层的沉积特征和成因。根据孢粉组合和^(14)C测年资料确定该硬土层为玉木冰期末期产物。从硬土层的分布广、厚度小、底面倾斜等特点和生物、粒度、重矿物等特征分析,属河漫滩洼地沉积或河漫滩型湖沼沉积。上海东部地下30m以内有一层硬土层(Q_3~3);上海西部有两层硬土层,第一硬土层属全新统,第二硬土层属上更新统上段。
The dark green hard soil layer of the upper member of Upper Pleistocene is key bed to divide Upper Pleistocene and Holocene. It has an important value to the reconstruction of paleogeographic environment. According to the studies on the paleontology, grain size, heavy minerals and trace elements, it is known that the dark green hard siol layer is a kind of the flood land depression or lake facies deposits formed in the end of Wurm-glaciation.14C dating shows that the age of this soil layer is 14750 ± 150 year B. P. and belongs to the end of Late Pleistocene. It is different from the 'Xiashu soil' and it should be above the 'Xiashu soil'. In addition, there is also a dark green hard soil layer of the Holocene in the western Shanghai, but it is distinctly different from the former in the sporo-pollen assemblage and foram assemblage of the underlaying layer.
出处
《东海海洋》
1989年第1期34-41,共8页
Donghai Marine Science
