出土琥珀产地指纹特征筛选与溯源方法研究——以汉代出土琥珀为例
Fingerprint Characteristic and Origin Traceability of Amber Artefacts——Application in Archaeological Amber from Han Dynasty
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摘要: 汉代是我国古代琥珀艺术发展的重要时期, 琥珀的出土数量、形制均在汉代时达到了一个新的高度。当采用无损谱学手段对风化、氧化的出土琥珀进行测试时, 样品表面的渣化、粉化状态会给无损测试和结果分析带来不小的挑战。本文选取来自波罗的海、缅甸和辽宁抚顺的113块不同氧化程度的琥珀原石样品作为参考样品, 以探明氧化蚀变给不同产地琥珀的谱学特征带来的具体影响, 利用了显微观察和红外光谱等测试手段采集了波罗的海、缅甸和抚顺琥珀氧化前后的特征。研究结果表明, 对于未氧化和氧化程度较低的琥珀原石样品, 通过红外光谱可以较好的对3个产地的琥珀进行区分。在对琥珀原石样品红外光谱数据处理后, 建立了用于出土琥珀产地溯源的红外光谱数据库和基于谱峰识别的产地溯源流程, 并结合模式识别分析方法建立了琥珀原石产地溯源模型, 该模型对113件琥珀原石的产地识别效果较好, 准确率达到了96.5%。采用琥珀原石样品红外光谱数据库分别建立适用于两地出土琥珀的产地溯源模型, 模型分类结果表明海昏侯墓出土琥珀均来自缅甸, 而湖南汉墓中3件出土琥珀来自波罗的海, 1件来自缅甸。由此可见, 在汉代时波罗的海琥珀和缅甸琥珀便已传入了中国并被广泛使用。Abstract: Han Dynasty was an important period in the development of ancient Chinese amber art, during which the quantity and shape of unearthed amber reached a new height. However, the deteriorated and oxidised skin of the excavated amber poses a significant challenge to non-destructive spectroscopy testing and result analysis. The article selected 113 pieces of rough amber samples with different degrees of oxidation from the Baltic region, Myanmar, and Fushun, China, were selected as reference samples to explore the specific effects of oxidation and erosion on the spectral characteristics of amber origin traceability. Microscopic observation and infrared spectroscopy were used to collect the characteristics of amber from the Baltic region, Myanmar, and Fushun before and after oxidation. The results showed that infrared spectroscopy could effectively distinguish amber from the three origins for unoxidised and slightly oxidised amber. After processing the infrared data of the rough amber samples, infrared database for the origin traceability of unearthed amber was established, and an origin tracing process based on spectral peak identification was developed. An amber origin tracing model was established using pattern recognition analysis, which achieved a good identification effect for 113 pieces of amber samples, with an accuracy rate of 96.5%. Origin tracing models applicable to amber unearthed from two different regions were separately established using the rough amber materials?infrared database. The classification results of the models indicated that the amber unearthed from the Haihun Marquis?Tomb all came from Myanmar, while 3 pieces of amber unearthed from Han Dynasty tombs in Hunan Province originated from the Baltic region and one from Myanmar. Therefore, it can be seen that amber both from the Baltic region and Myanmar were introduced into China and widely used during the Han Dynasty.