Multi-proxy reconstruction of the Holocene transition from a transgressive to regressive coastal evolution in the northern Jiangsu Plain, East China

摘要

The northern Jiangsu Plain (NJP) is an important part of the coastal plain in eastern China that has been affected by transgression and regression continuously throughout geological history; the region has well-recorded information on marine and terrestrial environmental changes since the Holocene. Previous studies have not reached a consensus regarding the timing and frequency of the occurrence of the Holocene transgression in the NJP, mainly due to the limitations of the dating methods and the difficulty in obtaining study materials. This study illustrated the results of integrated accelerator mass spectrometry ~(14)C analyses, optically stimulated luminescence dating, grain size distribution, geochemical elements, total organic carbon, and diatoms from the Gangxi profile, located in the NJP, to elucidate the sedimentary environmental evolution characteristics and responses to the relative changes in sea levels during the Holocene. Our results indicate that the sedimentary environment in the study area has changed significantly since nearly 13,550 ± 127 cal yr BP and experienced the transformation of a lacustrine sedimentary environment, tidal flat-shallow sea sedimentary environment, and lacustrine sedimentary environment. The time at which the seawater reached the study area was 7270 ±71 cal yr BP, while the occurrence of high sea levels was during 6570 ± 86-6260 ± 85 cal yr BP during the Holocene. In addition, six significant sea-level fluctuations occurred in the NJP during the Holocene. Consequently, the evolution of the sedimentary environment and the development of sedimentary strata in the coastal area of the NJP since 13,550 ± 127 cal yr BP were found to be related to global temperature and precipitation changes, sea-level fluctuations, and seawater intrusion. The research results provide an important reference for studying the land-ocean interaction zone respond to sea-level changes in the future.