Author(s)

Zhongyang Lin, Chaohui Zhu, Xudong Zhao, Guochun Yu, Liang Yi

Corresponding Author

Chaohui Zhu

Abstract

In order to study the stratigraphic division of the southern wing of the Yangtze River Delta in Quaternary and its coupling relationship with the palaeoenvironmental evolution, the Quaternary borehole BK01 (237.80m in depth; rate of core recovery > 96%) located in the southern wing of the Yangtze River Delta was taken as the research sample; sediment sporopollen analysis, micropalaeontology identification, granularity content analysis and isotopic dating were carried out. Combining with lithologic strata information revealed by the borehole, this paper discussed the palynological assemblages, the palaeoenvironmental evolution, the sedimentary sequence and palaeoclimate characteristics since the Pliocene epoch. The results showed that the study area has undergone many environmental changes since Pleistocene. There were 17 species of foraminifera belonging to 11 genera found in this area, including 16 benthic foraminifera and 1 plank tonic foraminifera. There were 8 species of Ostracod belonging to 8 genera. Pollen analysis showed that there were 37 species, including 18 species of arboreal pollen, 11 species of herbaceous plant pollen, and 8 species of fern spore. In the sporopollen assemblage, woody plant content was the highest, accounting for 85. 1%; fern spores accounted for about 8.7%; herbaceous pollen accounted for only 6.3%. According to borehole lithology, grain size, sporopollen assemblage and micropalaeontology analysis, the sedimentary environment records can be divided into 18 sporopollen assemblage zones and seven palaeoclimate cycles.

Keywords

Quaternary, sporopollen, sedimentary facies, stratigraphic chronology, southern wing of the Yangtze River Delta