Sedimentary charcoal records are used for understanding fire as an earth system process; however, no standardized laboratory methodology exists. Varying sample volumes and chemical treatments (i.e., type of chemical for length of time) are used for the deflocculation and extraction of charcoal from sediment samples. Here, we present the first systematic assessment of the effect of commonly used chemicals on charcoal area and number of fragments. In modern charcoal the area of fragments was significantly different depending on the chemical treatment. We subsequently applied H2O2 (33%), NaClO (12.5%), and HNO3 (50%) to a late-glacial–early Holocene paleorecord and tested different sample volumes. The effects of the treatments were consistent between modern and fossil experiments, which demonstrates the validity of applying results from the modern experiment to the fossil records. Based on our experiments we suggest (1) H2O2 33%, especially for highly organic sediments; (2) avoidance of high concentrations of NaClO for prolonged periods of time, and of HNO3; and (3) samples of 1 cm3 provided typically consistent profiles. Our results indicate that charcoal properties can be influenced by treatment type and sample volume, thus emphasizing the need for a common protocol to enable reliable multi-study comparisons or composite fire histories.

中文翻译：

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迈向木炭分析的标准化程序

沉积木炭记录用于将火理解为地球系统过程；但是，不存在标准化的实验室方法。不同的样品体积和化学处理（即时间长度的化学类型）用于解絮凝和从沉积物样品中提取木炭。在这里，我们首次系统地评估了常用化学品对木炭面积和碎片数量的影响。在现代木炭中，碎片的面积因化学处理而显着不同。我们随后应用了 H2○2(33%)、NaClO (12.5%) 和 HNO3(50%) 到晚冰期 - 早全新世古记录，并测试了不同的样本量。现代和化石实验之间的处理效果是一致的，这证明了将现代实验的结果应用于化石记录的有效性。根据我们的实验，我们建议 (1) H2○233%，特别是对于高有机质沉积物；(2) 避免长时间使用高浓度的 NaClO 和 HNO3; (3) 1 厘米的样品3提供通常一致的配置文件。我们的结果表明，木炭特性会受到处理类型和样本量的影响，因此强调需要一个通用协议来实现可靠的多研究比较或复合火灾历史。