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现代沉积物测年方法已经在海岸带地区得到了广泛应用,但在开放潮坪地区还存一定的问题,尤其是在通过210 Pb进行沉积速率计算时,常量初始浓度(constant initial concentration,简称CIC)模式和恒定补给速率(constant rate of supply,简称CRS)模式给出的结果通常差别很大,即使是与137 Cs时标法进行比对时,有时也不易解释.这严重制约了现代沉积物测年方法在开放潮坪及浅海区的应用效果.有鉴于此,选取了其中的1个典型站位的柱状样品,同时开展~(210)Pb_(exc)过量的~(210)Pb的CRS模式和CIC模式计算,并与137 Cs时标法进行对比,结合区域沉积历史数据,对~(210)Pb_(exc)的CRS模式和CIC模式的选择进行了综合分析,为现代沉积物测年在海岸带地区的应用和解释提供了过程参考.结果显示,对~(210)Pb_(exc)数据分段采用CIC模式获得的结果较CRS模式获得的更为可靠.这是因为海岸带地区,被潮流搬运来的沉积物更容易满足CIC计算模式所要求的前提条件,即沉积物中的~(210)Pb_(exc)初始比活度是恒定的.作为一般数据使用者,更倾向于通过~(210)Pb_(exc)测年方法(也就是CRS模式)能够获得每一层的年龄,但在海岸带地区应用该方法时就需要更加慎重.
Although modern sediment dating methods have been widely used in the coastal zone, there are still some problems in the open tidal flat area, especially in the calculation of deposition rate by 210 Pb. The initial initial concentration (CIC ) Mode and the constant rate of supply (CRS) model generally give very different results, sometimes difficult to interpret even when compared to the 137 Cs time-base method, which severely limits the effectiveness of modern sediment In view of this, a typical sample of columnar samples was selected and at the same time a ~ (210) Pb hypersensitive (210) Pb CRS Mode and CIC mode, and compared with the 137 Cs time-stamped method, combined with the regional sedimentary history data, a comprehensive analysis of the selection of ~ (210) Pb exc (exc) CRS mode and CIC mode is made for the modern sediment dating Which provides a process reference for application and interpretation in the coastal zone.The results show that the results obtained with the CIC mode for the ~ (210) Pb exc data are more reliable than those obtained with the CRS mode because of the coastal zone, The trend is to transport Shen The sediment can more easily satisfy the preconditions required by the CIC calculation model, that is, the initial specific activity of ~ (210) Pb_ (exc) in the sediment is constant, and as a general data user, (exc) dating method (that is, the CRS model) can obtain the age of each layer, but caution should be exercised when applying this method in the coastal zone.