Charcoal reflectance measurements: implications for structural characterization and assessment of diagenetic alteration
Charcoal reflectance measurements: implications for structural characterization and assessment of diagenetic alteration
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DOI：
10.1016/j.jas.2010.01.020
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发表时间：
2010-07-01
影响因子：
2.8
通讯作者：
Le Manquais, Katherine
中科院分区：
文献类型：
--
作者：
Ascough, Philippa L.;Bird, Michael I.;Le Manquais, Katherine
木炭是考古和古环境代用数据的宝贵来源。然而，越来越多的证据表明，生产条件可以强烈地影响木炭的沉积后蚀变。因此，生产温度的重建和对成岩蚀变潜力的了解都是非常重要的。在这里，我们使用平均随机反射率（Ro(mean)）结合其他化学表征方法来解决这些问题。Ro（平均值）是在受控条件下生产的一套现代模拟木炭和从考古和古环境沉积物中获得的一系列天然木炭样品中获得的。Ro（平均值）被证明是评估400℃及以上地层温度的可靠指标，即使在暴露于高氧化条件下也是如此。Ro（平均值）对于在300℃至400℃之间形成的样品也有用。然而，如果一组木炭暴露于氧化条件下，较低温度的木炭可能优先丢失。很明显，在较低温度下生产的木炭更容易受到化学氧化的影响，而且木炭的降解潜力是连续的，这取决于燃料材料和生产条件。(C) 2010 Elsevier Ltd.版权所有。
Charcoal is a valuable source of archaeological and palaeoenvironmental proxy data. However growing evidence suggests that production conditions can strongly influence post-depositional alteration of charcoal. Consequently, both reconstruction of production temperature and understanding of the potential for diagenetic alteration are of great interest. Here, we use mean random reflectance (Ro(mean)) in conjunction with other chemical characterization methods to address these questions. Ro(mean) was obtained for a suite of modern analogue charcoal, produced under controlled conditions, and for a series of natural charcoal samples, obtained from archaeological and palaeoenvironmental deposits. Ro(mean) proves to be a robust measure to assess formation temperature for samples produced at 400 degrees C and above, even after exposure to highly oxidizing conditions. Ro(mean) is also useful for samples formed between 300 degrees C and 400 degrees C. However, if an assemblage of charcoals has been exposed to oxidizing conditions, lower temperature charcoals may be preferentially lost. It is apparent that charcoal produced at lower temperatures is more highly susceptible to chemical oxidation, and that there is a continuum in charcoal degradation potential, dependant upon fuel material and production conditions. (C) 2010 Elsevier Ltd. All rights reserved.