Evolution Of The Sedimentary Environments Since The Late Pleistocene In Nantong Region

Nantong region is located in the front part of the northern wing of the Yangtze River Delta. Since the late Pleistocene, under the long-term interaction of the sea and rivers, the area has undergone a complete glacial-interglacial sedimentary cycles, forming a sedimentary layer of about 100-130 m thick. The sedimentary environments are diverse and complex. Comparing with the southern wing of the Yangtze River Delta, research of the study area still remains to be strengthened.We collects three cores, i.e. ZK01, ZK02(hydrogeological cores) and ZKA2(Quaternary standard core), which were all taken from Rudong, a county in Nantong region. Core logging and geophysical logging were simultaneously carried out. Combined with the data of volume susceptibility, grain size and 14 C dating of ZKA2, the stratigraphic framework of the study area was established and the paleo-environment reconstructed.The results show that:1) the strata of ZKA2 could be divided into three groups, i.e. Group Kunshan 106.4-87.73 m, Group Gehu 87.73-23.42 m, Group Qidong 23.42-0m; 2) the curves of the volume magnetic susceptibility and the grain size have a better consistency; 3) the area between ZKA2 and ZK01, ZK02 is presumed to be the northern boundary of the ancient Holocene Yangtze River; 4) the curves of natural voltage and apparent resistivity of ZK02 have five cyclical fluctuations from 104.25 m to 118.7m, which could be well correlated with the carbon dioxide curve of the Antarctic vostok ice core.