Assessing natural variation and the effects of charring, burial and pre-treatment on the stable carbon and nitrogen isotope values of archaeobotanical cereals and pulses
Assessing natural variation and the effects of charring, burial and pre-treatment on the stable carbon and nitrogen isotope values of archaeobotanical cereals and pulses
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DOI：
10.1016/j.jas.2013.01.032
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发表时间：
2013-12-01
影响因子：
2.8
通讯作者：
Heaton, T. H. E.
中科院分区：
文献类型：
--
作者：
Fraser, R. A.;Bogaard, A.;Heaton, T. H. E.
本研究的目的是评估烧焦的古植物谷物和豆类种子δ C-13和δ N-15值的潜力，以提供作物生长条件的证据，并作为古饮食研究的潜在组成部分。为了可靠地解释考古植物三角洲C-13和三角洲N-15值，有必要考虑到炭化，埋葬和实验室预处理程序的影响。我们研究了现代谷物和豆类材料中的大量δ C-13，δ N-15，%C，%N和C：N比的炭化和掩埋效果，以及现代和考古植物学炭化材料的酸碱酸（阿坝）预处理的清洁效果。我们的研究利用散装谷物和种子样品，以帮助解释穗内/豆荚和植物之间的变异性三角洲C-13和三角洲N-15值。在相对较低的温度和较长的时间（230摄氏度，长达24小时）加热有利于形成保存良好，未变形的烧焦谷物颗粒和豆类种子。加热24小时对δ N-15值有系统和可预测的影响，谷物和豆类种子平均增加约千分之一，对δ C-13值没有一致的影响。δ N-15的增加可能是由于较轻的N-14通过含N挥发物的损失。埋藏（长达2年）和阿坝预处理对δ C-13或δ N-15值没有显着影响。预处理后，然而，%C和%N含量的archaeobotanical材料更接近于现代烧焦的谷物和种子，这表明archaeobotanical仍然积累非结构材料在埋葬过程中，但保留其原有的碳和氮含量。因此，%C，%N含量和C：N比可以提供有用的标准，评估古植物保存。(C)2013爱思唯尔有限公司保留所有权利。
The aim of this study is to assess the potential of charred archaeobotanical cereal grain and pulse seed delta C-13 and delta N-15 values to provide evidence of crop growing conditions and as a potential component of palaeodietary studies. In order to reliably interpret archaeobotanical delta C-13 and delta N-15 values it is necessary to take into account the impact of charring, burial and laboratory pre-treatment procedures. We examine the effects of charring and burial on bulk delta C-13, delta N-15, %C, %N and C:N ratios in modern cereal and pulse material, and of cleaning by acid base acid (ABA) pre-treatment on modern and archaeobotanical charred material. Our study utilised bulk grain and seed samples to help account for within-ear/pod and between-plant variability in delta C-13 and delta N-15 values. Heating at relatively low temperatures and for prolonged times (230 degrees C for up to 24 h) is conducive to the formation of well preserved, undistorted charred cereal grain and pulse seed. Heating for 24 h has a systematic and predictable effect on delta N-15 values, with increases of around 1 parts per thousand on average in cereal grains and pulse seeds, and no consistent impact on delta C-13 values. Increases in delta N-15 are likely due to the loss of lighter N-14 via N-containing volatiles. Burial (for up to 2 years) and ABA pre-treatment have no significant effects on delta C-13 or delta N-15 values. After pre-treatment, however, the %C and %N contents of the archaeobotanical material more closely resembles that of the modern charred grains and seeds, suggesting that archaeobotanical remains accumulate non-structural material during burial but retain their original carbon and nitrogen content. Therefore %C, %N contents and C:N ratios can provide useful criteria for assessing archaeobotanical preservation. (C) 2013 Elsevier Ltd. All rights reserved.