Geochemical record of core PJ in Yangtze River Delta and implications for variations in paleoenvironment

Geochemical elements, significant indicator of environmental change,have been widely used in paleoenvironment research. By comparative analysizing of sediment's geochemical characterstics of core PJ and core ZX-1, almost opposite relations was found between them. In Holocene, there are repeated transgression-regression cycles and the deposition profile of core PJ was in the critical zone of transgression-regression. When climate was warm and humid, sea-level rose, the sedimentary environmental salinity increased and ability of element eluviate-leaching were weak, geochemical elements can not be effectively separated. On the contrary, when climate was dry and cold, sea-level became lower, the role of the element eluviate-leaching was enhanced, and different geochemical elements can be effective separated. This mechanism enables that indicators significance of core PJ's geochemistry element changing is the opposite direction to other regions.