Abstract:
On the basis of accelerator mass spectrometry (AMS)
14C ages of eight Holocene core sediment samples from the south coast of Laizhou Bay, along with the analyses of sedimentary structure and foraminifera characteristics, the authors identified the sea level indicators and, on such a basis, reconstructed the Holocene relative sea level changes. The rapid sea level rise before ca. 9200cal BP probably resulted in the local postglacial flooding when the relative sea level reached -21.5m, followed by the decrease of sea level rise to 2mm/a from 9200cal BP to 8400cal BP. During 8400~8000cal BP or so relative sea rose rapidly from -14m to -5.5m with a rate of 33mm/a. A stagnation or slight decline of the sea level was found which lasted hundreds of years from 8000cal BP to 7600cal BP. After 7600cal BP, this equilibrium was again interrupted by the rapid sea level rise of more than 13mm/a, and the relative sea level passed over the modern elevation at around 7000cal BP with more than 5m rise magnitude. After about 7000cal BP, the relative sea level rose slowly at the rate of 3mm/a, and reached its high stand of 2~3m height at around 6000cal BP. And then it fell slowly down to the present level. There were three times of rapid rise in Early Holocene, probably corresponding to three meltwater pulse events of MWP-1C, 8.2ka event and MWP-2, respectively. The global ice melting tended to be stagnant in the Middle Holocene; in virtue of the slow rate of local basin subsidence, the sea level highstand of +2~+3m was presented under the effect of Glacial Isostatic Adjustment (GIA).