Carbonate 14C Background: Does It Have Multiple Personalities?
Carbonate 14C Background: Does It Have Multiple Personalities?
复制标题
DOI：
10.1017/s0033822200037978
复制
发表时间：
2001
期刊：
影响因子：
8.3
通讯作者：
M. Nadeau;P. Grootes;A. Voelker;F. Bruhn;A. Duhr;Angelika Oriwall
中科院分区：
文献类型：
--
作者：
M. Nadeau;P. Grootes;A. Voelker;F. Bruhn;A. Duhr;Angelika Oriwall
对几种碳酸盐背景材料（矿物（IAEA C1 卡拉拉大理石和冰岛双晶石）或生物（有孔虫和软体动物））的放射性碳浓度的测量表明，不同材料的表观年龄可能有很大差异。使用从矿物样品中获得的 0.07 pMC 作为处理空白，有孔虫和软体动物背景样品的结果（从 0.12 到 0.58 pMC (54.0-41.4 ka)）显示出物种特异性污染，该污染在来自多个沉积物核心的几个单独的贝壳和有孔虫上繁殖。不同的清洁尝试已被证明是无效的，甚至更强的措施，例如在常规制备之前对样品进行逐步水解或浸出，也没有给出任何污染源的迹象。鉴于这些结果，使用矿物背景材料来评估较旧的未知生物碳酸盐样品（> 30 ka）的年龄被证明是不够的。使用与未知样品相同物种和来源的背景样品至关重要，如果无法获得此类材料，则应使用通用生物样品，例如混合有孔虫样品。还介绍了我们新型模块化碳酸盐样品制备系统的描述。
Measurements of the radiocarbon concentration of several carbonate background materials, either mineral (IAEA C1 Carrara marble and Icelandic double spar) or biogenic (foraminifera and molluscs), show that the apparent ages of diverse materials can be quite different. Using 0.07 pMC obtained from mineral samples as a processing blank, the results from foraminifera and mollusc background samples, varying from 0.12 to 0.58 pMC (54.0-41.4 ka), show a species-specific contamination that reproduces over several individual shells and foraminifera from several sediment cores. Different cleaning attempts have proven ineffective, and even stronger measures such as progressive hydrolization or leaching of the samples prior to routine preparation, did not give any indication of the source of the contamination. In light of these results, the use of mineral background material in the evaluation of the age of older unknown samples of biogenic carbonate (>30 ka) proves inadequate. The use of background samples of the same species and provenance as the unknown samples is essential, and if such material is unavailable, generic biogenic samples such as mixed foraminifera samples should be used. The description of our new modular carbonate sample preparation system is also introduced.