A comparative study on recent sedimentation rates in Lake Donghu, Wuhanwith ~(210)Pb and ~(137)Cs dating techniques

Two undisturbed sediment cores at 90 cm and 150 cm at the StationⅠ and Ⅱ in Lake Donghu, Wuhan, were collected respectively. Environmental ()~(210)Pb and ()~(137)Cs dating techniques were applied to determine recent sedimentation rates. The results showed that: (1)The recent sedimentation rates of sediment at StationⅠandⅡdetermined by ()~(210)Pb are 8.7 mm/a and 6.9 mm/a. While the recent sedimentation rates determined by ()~(137)Cs are 7.4 mm/a and 5.8 mm/a. After contrasting ()~(210)Pb and ()~(137)Cs dating techniques, this paper figured that: (1)()~(137)Cs dating technique was more reliable. ((2) The) recent sedimentation rates gradually decreased from Station Ⅰto Station Ⅱdue to the differences of substance supply and sedimentary environments. (3) The recent sedimentation rates from 1964 to 1975 were greatest, and it decreased from 1964 to 2002, which were both possibly attributed to human activities. (4) The sediment at Station Ⅰand Station Ⅱwas disturbed by biodisturbance and mechanic disturbance.