Geochemistry and environment evolution of Core E in the Laizhou Bay since last stage of Middle Pleistocene

Geochemistry analysis has been done on Core E (37°07'N,118°55'E; depth:82.1 m) taken from the Laizhou Bay in 1994.Nine kinds of invariable elements,15 kinds of microelements and the content of lime carbonate are measured by means of ICP.The results indicate that most of the in variable elements and microelements in Core E show significant changes in the boundary stratotype,and the ratios between elements (Mn/Fe,Sr/Ba,Ti/Al) in particular.So they can be used as characteristic indicator to stratigraphic division of Quaternary.The changes of invariable elements are primarily con trolled by the host minerals,and they mainly indicate the provenance as well as the sedimentation and depositional environment.Several elements,such as Fe,Al,Ca,Mg,Mn and Ti,are very sensitive to the provenance and environment.The distribution of microelements differs in four depositional periods:last stage of Middle Pleistocene,last interglacial period,last glacial period and Recent epoch,and espe cially in the "cold period" and "warm period".The loops in the cycle curves of the most microelements correspond with the sand bed sediments,among which there are six sand units representing "warm period" sediments,and one representing "cold period" sediments.The carbonate is on the high side in the aeolian silt sediments formed in the glacial lowering of sea level in Core E,but on the low side in the transgressive sand beds formed in the interglacial period.The content variation of carbonate has a direct bearing on the grain size and the styles of sediments,and is a good indicator to the climate,environment and stratigraphic division.