(Table 1) Radionuclides and ESR dating of sediment cores PS1535-10 and PS1535-8

ESR-spectra of foraminifera in arctic sediment cores display the [CO2]- -signal (g=2.0006). Research on the thermal behaviour of the [CO2]- -signal shows that both natural and artificial irradiation generates a precursor and a thermal unstable component of the [CO2]- -signal. The precursor can be transfered to the stable radical, and unstable radicals can be removed by heating. The signal-change by heating depends on the irradiation dose. Because of the varying response on thermal treatment, the dose-response curves show systematic differences depending on the applied procedure (single- or multi-aliquot method with or without heating). A model for the description of the [CO2]- -signal-change is presented. The combination of two exponential saturation functions seems to be an adequate analytical description of the dose-response curve of the [CO2]- -signal in foraminifera. Due to the limited thermal stability this signal can be used for dating foraminifera with ages up to about 190 ka.

北极沉积岩心中的有孔虫 ESR 光谱展现出 [CO2]-(g=2.0006) 信号。对 [CO2]-(g=2.0006) 信号的热行为研究揭示，无论是自然还是人工辐射均能产生该信号的先导成分和热不稳定组分。该先导成分可转化为稳定自由基，而不稳定自由基则可通过加热去除。加热引起的信号变化取决于辐射剂量。由于热稳定性存在差异，剂量-响应曲线在所采用的方法（单份或多份样本方法，是否加热）上表现出系统性的差异。本文提出了一种描述 [CO2]-(g=2.0006) 信号变化的模型。将两个指数饱和函数的结合似乎是对有孔虫中 [CO2]-(g=2.0006) 信号的剂量-响应曲线进行解析描述的恰当方法。鉴于其有限的热稳定性，此信号可用于对约 190 ka 之前的有孔虫进行年代测定。