关键词: ²¹⁰Pb, ¹³⁷Cs, 沉积速率, 乌梁素海, 内蒙古

Abstract:

Environmental ²¹⁰Pb and ¹³⁷Cs dating techniques were applied to determine recent deposition rates.²¹⁰Pb and  ¹³⁷Cs were analyzed for the Wuliangsu lake sediment core. In the core, there was an obvious peak in 1963, which was an important age characteristic for the Wuliangsu lake sediments. The deposition rate of the Wuliangsu lake was about 0.47 cm/a by ¹³⁷Cs time marker (1963).²¹⁰Pb (CRS) dating showed a relatively good agreement with the  ¹³⁷Cs dating. The limit depth of ²¹⁰Pb was 74 cm, which corresponded to the year of 1892. The abnormal variations of ²¹⁰Pb activity could be found in the profile. The highest value of  ²¹⁰Pb at the depth of 20 cm might be linked with the maximum value in 1963 due to the nuclear bomb test producing both ¹³⁷Cs and ²¹⁰Pb. The deposition rate was changeable in the Wuliangsu lake by analyzing the depth and ages, which showed that the sedimentation environment was changeable in recent 113 years either. The combination of the two dating methods was useful to understand the substantial sedimentation process of the wetland where sedimentation rates change rapidly.
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Key words: ²¹⁰Pb, ¹³⁷Cs, deposition rate, Wuliangsu lake, Inner Mongolia