MODERN SEDIMENTATION RATE AND SEDIMENTATION PROCESS IN BOHAI BAY
Du Ruizhi Liu Guoxian Yang Songlin Zhou Yihua Zhang Bing (Institute of Marine Environmental Protection, National Bureau of Oceanography, Dalian, China, 166023)
210Pb dating has determined modern sedimentation rate for 9 cores from Bohai Bay. It is found that sedimentation rate is relatively high off the Haihe River mouth (generally over 15mm/yr, and even up to 40-50mm/yr near the bay apex), and gradually decreases in anchorage and outer sea area, usually less than 8mm/yr. Radioactive profiles of the sediments have revealed important events in modern sedimentary environments, core column at site 1041 records the time of the Huanghe River flood and channel changes; and 210Pb profile from site 844 reflects the"instant accumulation"caused by human activities. We think that studies of modern sedimentation rate can be able to unco ver both man-made and natural events and this is very significant to ocean development engineering and scientific researches of environment.