Saltmarshes, wetlands, inter-tidal mudflats are highly productive natural ecosystems with significant ecological value. ²¹⁰Pb and ¹³⁷Cs have been used for establishing chronologies at a centennial scale in these sediments. They are relevant for assessing how saltmarshes are vulnerable to climate change, natural hazards and contamination from human inputs. This paper aims to review and adapt existing methods for the ²¹⁰Pb-based radiometric dating of these sediments where the subterranean production and decay of OM are sources of achronicity. This limits the use of the basic assumption of considering the sediment as a continuous medium. From the available evidence, ²¹⁰Pb fluxes onto sediments may be mediated by the activities bound to the mass flows, suggesting that models assuming a constant flux should be handled with care. The activity concentrations of excess ²¹⁰Pb required by CF-CS, CIC and TERESA radiometric models must be those of the sediment mineral fraction, while CRS and PLUM can work with the composite sediment matrix. A review of these issues and application of the models is illustrated with new data from two recent saltmarsh sediment cores. The effects of non-ideal boundary conditions in radiometric dating and the system time-average of ¹³⁷Cs fluxes are discussed. Although specific to vegetated saltmarshes, this topic and the present results have generic applications for other vegetated coastal sediments.

盐沼，湿地，潮间带滩涂是具有重要生态价值的高产自然生态系统。²¹⁰ Pb和¹³⁷ Cs已用于在这些沉积物中建立百年尺度的年代学。它们与评估盐沼如何易受气候变化，自然灾害和人类输入污染的影响有关。本文旨在审查和适应现有方法对这些沉积物进行基于²¹⁰ Pb的放射性测年的方法，其中地下生产和OM衰变是非时性的来源。这限制了将沉积物视为连续介质的基本假设的使用。根据现有证据，²¹⁰沉积物上的铅通量可能受束缚在物质流中的活动的介导，这表明应该谨慎处理假定流量恒定的模型。CF-CS，CIC和TERESA辐射模型需要的²¹⁰ Pb的活度浓度必须是沉积物矿物分数的活度浓度，而CRS和PLUM可以与复合沉积物基质一起使用。这些问题的回顾和模型的应用用两个近期盐沼沉积物岩心的新数据进行了说明。讨论了非理想边界条件对辐射测年和¹³⁷ Cs通量的系统时间平均的影响。尽管特定于植被盐沼，但该主题和当前结果对其他植被沿海沉积物具有一般性应用。