Identifying the geochemical taphonomy of the osteological material from Katsambas rockshelter

We report analytical work undertaken in order to identify the geochemical taphonomy of the osteological collection (human and animal bones) recovered from a 1950s excavation at Katsambas, a small cavity in the marly limestone on the west bank of Kairatos River, Crete. The site had funerary use and yielded material of Neolithic and Minoan age with poor stratigraphical association. Disintegration of provenance labels from bags has introduced further uncertainty about the contexts of recovery. Samples of human and animal bones that macroscopically appear to belong to three taphonomic categories were studied by means of FT-IR spectroscopy, TEM microscopy and REE analysis to explore the taphonomical processes the bones have undergone. Although not novel in palaeontological research the use of REE opens a new path to investigating poorly provenanced osteological collections from old excavations. Such geochemical work offers a proxy to their relative dating through the evaluation of the time span bones have remained in the sediments and their respective taphonomic histories.     

New parameters for the characterization of diagenetic alterations and heat-induced changes of fossil bone mineral using Fourier transform infrared spectrometry

Diagenetic alteration may limit the potential use of the biogenic composition of fossil bone as a reliable source of information for dietary, environmental and climatic reconstructions. One of the key parameters used to determine the state of preservation of fossil remains is their crystallinity. This can be evaluated by means of infrared spectroscopy, measuring the “splitting factor” (IRSF). However, the crystallinity may fail to describe the extent of chemical and mineralogical changes occurring during fossilization, and cannot be used alone as a reliable indicator of biogenic signal preservation.     

A new statistical approach for determining the crystallinity of heat-altered bone mineral from FTIR spectra

The crystallinity of bone mineral represents an established method of measuring heat-induced change and is of importance to fields including material science, clinical science, anthropology and archaeology. A commonly used technique involves the calculation of the Crystallinity Index (CI) using selected peaks from Fourier Transform Infrared (FTIR) absorbance spectra. However, the choice of peaks has to date not been statistically justified. In this study a novel application of statistical techniques to the FTIR spectra of bone samples burned in the range 100 °C–1100 °C has been used to identify 5 new spectral indices of heat-induced crystallinity change. The validity of the new indices was tested by using a statistical classification model (LDA) to predict the burning temperature of a set of 108 bone samples burned between 100 °C and 1100 °C. A correct classification rate (CCR) of 97.2% was obtained when a combination of 4 indices including the CI was used. This was significantly better than the CCR of 66.7% which was obtained when the CI was used on its own.     

Accessing Hunter-Gatherer site structures using Fourier transform infrared spectroscopy: applications at a Taltheilei settlement in the Canadian Sub-Arctic

The results of Fourier transform infrared spectroscopy on soils and caribou bone from a Taltheilei culture settlement in northern Canada contribute to developing micro-archaeological approaches suitable for locating and characterizing hearth and midden features on hunter-gatherer sites. A weak yet pervasive signal for montgomeryite was developed from the diagenesis of dispersed ash and caribou processing residues. Disordered calcite, carbonate hydroxylapatite, charcoal, and burned bone in two pit-house hearth deposits indicate that both wood and bone were used for fuel. Crystallinity indices and carbonate/phosphate ratios for bone indicate high intensity burning. These data, in tandem with the presence of semi-subterranean dwellings, demonstrate that this particular tundra-based encampment was occupied during cold seasons, a type of settlement behaviour previously unrecognized in the Taltheilei archaeological record. Our results confirm that Fourier transform infrared spectroscopy is an accessible, rapid, and cost effective means of discovering micro-archaeological evidence valuable for reconstructing hunter-gatherer site structures.     

The application of a new method of Fourier Transform Infrared Spectroscopy to the analysis of burned bone

A new method of Fourier Transform Infrared Spectroscopy (FTIR) is applied to the analysis of burned bones. FTIR analyses were undertaken to examine changes in Crystallinity Index (CI), Ca/P and C/C ratios in bone experimentally burned to known, but varying, temperatures and durations. Three sample groups were used to assess the new FTIR method. Blind tests were performed to assess the use of the CI for predicting burning conditions. The results suggested that the new method of FTIR was preferable to the traditional approach, but that CI is affected by factors other than temperature of burning, including the method of FTIR used, and that predictions of burning conditions in archaeological material may not extend beyond that of ‘high’ or ‘low’ intensity of burning.     

明代丝织物保存状态的分析研究

考古出土丝绸保存状态的研究对丝绸的科学保护具有重要的指导意义。本工作选取丝纤维中最主要的桑蚕丝及柞蚕丝作参照,以考古出土的明代丝绸为研究对象,通过荧光电子显微镜观察丝绸的纤维结构形貌、傅立叶变换红外光谱仪分析化学结构,结合X-射线衍射仪分析结晶度,用薄层色谱分析丝绸中氨基酸的组成,并进一步用紫外-可见光分光光度法分析丝绸中酪氨酸含量等方法,对一件出土的明代丝绸织物的保存状态进行了科学分析研究。分析结果表明,明代丝绸为桑蚕丝,纤维丝松散且断裂较多,结晶度下降,多数氨基酸含量明显降低,只检测到甘氨酸、丙氨酸、丝氨酸、酪氨酸与谷氨酸。酪氨酸含量为13.78%,比参照桑蚕丝含量低。