210Pb Characteristic in the Sediment Cores from the Pearl River Mouth and Its Environmental Implication

Key words: 
• sedimentation rates

Abstract: Based on the principle of lead 210 excess decaying and the characteristics of modern lead 210 sediment profiles of 14 sediment cores from the Pearl River mouth and its adjacent areas, a Fourier series based model for counting variation sediment rates was built. Sediment series was analyzed at the Pearl River mouth within 50 sediment years. The lead 210 of each sediment cores was calculated in the model for counting variation sedimentation rates and gained more specific data of the sedimentation process. Sedimentation rates, dating results and those relations between the sedimentary environmental at the same time were analyzed. The result shows that sedimentation rates are distinct from each other greatly at different stations. The average sediment rates of the stations were 7.25cm/a,5.36cm/a,3.26cm/a,3.03cm/a,1.58cm/a, respectively. The sedimentation rates variation at different stations has good correlation with the flooding, storms, anthropological activities, geomorphologic evolvement and other environmental elements at the estuary within the same periods. It verified that the characteristic of lead 210 of the sediment profiles calculated from the Fourier series based model for counting variation sediment rates can explain the environmental statues/changes at the same time. The model also made experiences for other estuaries which would analyses the sediment rates from the characteristic of lead 210 of the sediment cores.