Challenges in sample processing within radiocarbon dating and their impact in 14C-dates-as-data studies
Challenges in sample processing within radiocarbon dating and their impact in 14C-dates-as-data studies
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DOI：
10.1016/j.jas.2019.105043
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发表时间：
2020-01-01
影响因子：
2.8
通讯作者：
Higham, Thomas
中科院分区：
文献类型：
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作者：
Becerra-Valdivia, Lorena;Leal-Cervantes, Rodrigo;Higham, Thomas
几十年来，研究人员利用放射性碳测年数据来重建古代人类人口的趋势。该分析的首要假设是日期的频率与过去人类活动的强度成正比。因此，汇总或以其他方式汇总的日期的分布用于推断人口密度和流动模式。然而，工作人员在不同程度上解决了与这一分析相关的许多基本假设，如果这些假设是错误的且没有严格考虑，就会引入偏见，歪曲活动的规模，并最终证明在考古学解释中具有误导性。在这方面，迄今为止的研究主要集中在纠正考古遗址和构成材料随时间退化的影响、校准不规则性以及所用统计方法的有效性。然而，与放射性碳测年中的样品处理直接相关的假设在“C-14 日期数据”分析中讨论较少。例如，假设所有碳质材料都会产生足够的内源碳用于放射性碳测量。然而，放射性碳测年中的样本失败很常见，并且很大程度上取决于沉积后环境等确定性因素。因此，所分析的放射性碳日期集代表了与可靠性无关的成功测量。在这项工作中，我们讨论了放射性碳处理中的挑战所带来的偏差及其对 C-14 日期数据研究的影响。
For decades, researchers have employed sets of radiocarbon dates to reconstruct trends in ancient human populations. The overarching assumption in this analysis is that the frequency of dates is proportional to the magnitude of past human activity. Thus, the distribution of summed or otherwise summarized dates is used to extrapolate population density and mobility patterns. There are, however, a number of underlying assumptions associated with this analysis that workers address to varying degrees and which, if false and not critically accounted for, will introduce bias, misrepresent the magnitude of activity, and ultimately prove misleading in archaeological interpretations. In this regard, research has so far mainly focused on correcting for the effects of time-dependent degradation of archaeological sites and constituent materials, calibration irregularities, and the efficacy of the statistical methods used. Assumptions directly related to sample processing in radiocarbon dating, however, are less discussed in 'C-14-dates-as-data' analyses. It is, for example, assumed that all carbonaceous materials will yield sufficient, endogenous carbon for radiocarbon measurement. Yet sample failure in radiocarbon dating is common and contingent on, largely, deterministic factors such as post-depositional environment. Sets of radiocarbon dates analyzed, therefore, represent successful measurements independent of reliability. In this work, we discuss the biases introduced by challenges in radiocarbon processing and their impact on C-14-dates-as-data studies.