The use of reflectance values for the interpretation of natural and anthropogenic charcoal assemblages
The use of reflectance values for the interpretation of natural and anthropogenic charcoal assemblages
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DOI：
10.1007/s12520-009-0018-z
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发表时间：
2009-10
影响因子：
2.2
通讯作者：
Laura C. McParland;M. Collinson;A. Scott;G. Campbell
中科院分区：
文献类型：
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作者：
Laura C. McParland;M. Collinson;A. Scott;G. Campbell
木炭组合在自然和考古环境中都存在。油下抛光块中木炭的胞壁反射率值可作为地层温度的指标。本文的目的是(1)确定是否可以利用反射率数据区分不同烟火活动中的野火木炭和人类学木炭；(2)通过分析实验室生产的再烧焦的木炭和使用木炭燃料的传统青铜铸件，确定是否可以在考古记录中识别再烧焦(即使用木炭燃料)。来自代表木炭燃烧的组合的反射频率数据，在这种情况下是铁冶炼和青铜铸造，表明温度从木炭生产的平均值(>；475°C)到在随后的工艺中达到的最高温度(>；475到>；1,100°C)。相比之下，野火木炭的反射率范围从几乎无法测量的材料(最小值从0.06%到0.56%Ro)到最大反射率值从1.65%Ro(Tilford)到3.8%Ro(Zacca)。野火的平均反射率表明温度在325-400°C之间，因此可以明显区别于木炭燃烧过程的温度。实验室生产的重新烧焦的木炭具有经历过的最高温度的反射率值；反射率值不受原始形成温度的限制。高温最容易通过燃烧木炭燃料实现，因此高反射率的木炭很可能代表再烧焦的木炭。因此，这种定量反射方法可用于考古学中确定涉及火的人类过程中木炭形成的最低温度，可以指示使用木炭或木材作为燃料的可能性，并可以区分高温人为木炭和自然野火形成的木炭。
Charcoal assemblages occur in both natural and archaeological settings. Cell wall reflectance values of charcoal in polished blocks under oil provide a proxy for temperature of formation. This paper aims to (1) determine whether wildfire charcoals and anthropological charcoals from various pyrotechnical activities can be distinguished using reflectance data and (2) establish if re-charring (i.e. use of charcoal fuel) can be recognised in the archaeological record through analysis of laboratory-produced re-charred charcoals and charcoals from an experimental iron smelt and traditional bronze casting which utilised charcoal fuel. Reflectance frequency data from assemblages representing burning of charcoal, in this case of iron smelting and bronze casting, indicates temperatures from above the mean value of charcoal production (>475°C) up to the maximum temperature reached in the subsequent process (i.e. >475 to >1,100°C). In contrast, wildfire charcoals showed a range of values including material with barely measurable reflectance (minimum values from 0.06% to 0.56%Ro) to maximum reflectance values varying from 1.65%Ro (Tilford) to 3.8%Ro (Zacca). The mean wildfire reflectance indicated temperatures in the range 325–400°C, which can therefore clearly be distinguished from that of the charcoal burning processes. The laboratory-produced re-charred charcoals take on the reflectance value of the highest temperatures experienced; reflectance values were not constrained by the original temperature of formation. High temperatures are most easily achievable by the burning of charcoal fuel, and hence high reflectance charcoals are likely to represent re-charred charcoal. Therefore, this quantitative reflectance method can be used in archaeology to determine the minimum temperature of formation of charcoals in anthropological processes which involve fire, can indicate the likelihood of use of charcoal or wood as fuel and can distinguish between an assemblage of high temperature anthropogenic charcoals and charcoals formed from natural wildfire.