Grupe Gisela, Klaut Dominika, Mauder Markus, Kröger Peer, Lang Amei, Mayr Christoph, Söllner Frank
Biozentrum, Ludwig-Maximilians-Universität München, Germany.
Lehrstuhl für Datenbanksysteme und Data Mining, Ludwig-Maximilians-Universität München, Germany.
Rapid Commun Mass Spectrom. 2018 Oct 15;32(19):1711-1727. doi: 10.1002/rcm.8218.
Due to the spatial heterogeneity of stable isotope ratios of single elements measured in attempts to georeference bioarchaeological finds, multi-isotope fingerprints are frequently employed under the assumption that similar isotopic signatures are indicative of similar shared environments by the individuals studied. The extraction of the spatial information from multi-isotope datasets, however, is challenging.
Gaussian mixture clustering of six- to seven-dimensional isotopic fingerprints measured in archaeological animal and human bones was performed. Uncremated animal bones served for an isotopic mapping of a specific reference area of eminent archaeological importance, namely the Inn-Eisack-Adige passage across the European Alps. The fingerprints consist of Sr/ Sr, Pb/ Pb, Pb/ Pb, Pb/ Pb, Pb/ Pb, and Pb/ Pb ratios, and δ O values in uncremated bone apatite, while the thermally unstable δ O values of human cremations from this region were discarded.
The bone finds were successfully decontaminated. Animal and human isotope clusters not only reflect individual similarities in the multi-isotopic fingerprints, but also permit a spatial allocation of the finds. This holds also for cremated finds where the δ O value is no longer informative. To our knowledge, for the first time Pb stable isotopes have been systematically studied in cremated skeletal remains and proved significant in a region that was sought after for its ore deposits in prehistory.
Gaussian mixture clustering is a promising method for the interpretation of multi-isotopic fingerprints aiming at detecting and quantifying migration and trade.
由于在尝试对生物考古发现进行地理定位时所测量的单一元素稳定同位素比值存在空间异质性，多同位素指纹图谱经常被采用，其假设是相似的同位素特征表明所研究个体共享相似的环境。然而，从多同位素数据集中提取空间信息具有挑战性。
对考古动物和人类骨骼中测量的六到七维同位素指纹图谱进行高斯混合聚类。未火化的动物骨骼用于对一个具有重要考古意义的特定参考区域进行同位素测绘，即穿越欧洲阿尔卑斯山的因河 - 艾萨克河 - 阿迪杰河通道。指纹图谱由未火化骨磷灰石中的(^{87}Sr/^{86}Sr)、(^{206}Pb/^{204}Pb)、(^{207}Pb/^{204}Pb)、(^{208}Pb/^{204}Pb)、(^{207}Pb/^{206}Pb)和(^{208}Pb/^{206}Pb)比值以及(\delta^{18}O)值组成，而该地区人类火化遗骸中热不稳定的(\delta^{18}O)值被舍弃。
骨骼发现物成功去污。动物和人类同位素聚类不仅反映了多同位素指纹图谱中的个体相似性，还允许对发现物进行空间定位。对于(\delta^{18}O)值不再具有信息价值的火化发现物也是如此。据我们所知，首次在火化骨骼遗骸中系统研究了铅稳定同位素，并证明其在史前时期因其矿床而备受追捧的一个地区具有重要意义。
高斯混合聚类是一种有前景的方法，可用于解释旨在检测和量化迁移与贸易的多同位素指纹图谱。
