Characteristic burn temperature markers of bones as revealed by electron paramagnetic resonance (original) (raw)
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Analytical and Bioanalytical Chemistry, 2008
Derivative Fourier transform infrared (FTIR) spectroscopy and curve fitting have been used to investigate the effect of a thermal treatment on the ν 1ν 3 PO4 domain of modern bones. This method was efficient for identifying mineral matter modifications during heating. In particular, the 961, 1022, 1061, and 1092 cm−1 components show an important wavenumber shift between 120 and 700 °C, attributed to the decrease of the distortions induced by the removal of CO32− and HPO42− ions from the mineral lattice. The so-called 1030/1020 ratio was used to evaluate crystalline growth above 600 °C. The same analytical protocol was applied on Magdalenian fossil bones from the Bize–Tournal Cave (France). Although the band positions seem to have been affected by diagenetic processes, a wavenumber index—established by summing of the 961, 1022, and 1061 cm−1 peak positions—discriminated heated bones better than the 1030/1020 ratio, and the splitting factor frequently used to identify burnt bones in an archaeological context. This study suggest that the combination of derivative and curve-fitting analysis may afford a sensitive evaluation of the maximum temperature reached, and thus contribute to the fossil-derived knowledge of human activities related to the use of fire.
2019
FTIR spectroscopy has played an important role in recent attempts to understand the use of fire in prehistory. It has been used in the identification of heat altered sediment and bone. For the latter, the presence of the OH libration band at ca. 630cm-1 in the FTIR spectrum of an archaeological bone has been assumed to be indicative of bone that has been altered by fire. However, no ad-hoc research has explored whether this FTIR band could result from other ambient temperature diagenetic processes, or what the effects of heating variables may be on the appearance of this band. Here, I report a study designed to address this lacuna, and apply the results to the collection of fauna at Wonderwerk Cave from the Oldowan context. Using samples of cortical bone from micro-and macrofauna, I carried out a series of heating experiments to explore the change in FTIR spectra depending on temperature and duration of exposure to heat. Results demonstrate that the 630cm-1 peak is indeed diagnostic of burning, and indicate that microfauna are particularly useful indicators of burning activity when subjected to FTIR analysis. I hypothesize that the 630cm-1 peak is the result of the formation of pure hydroxyapatite, which appears to form above temperatures of 537°C. The results of this research were applied to the micro-and macrofauna collection of Wonderwerk Cave, South Africa, from the Earlier Stone Age context of 1.78Ma and older. Our results demonstrate that the majority of the bones from this context were burnt above 537°C.
In order to gain insight into the timing and nature of hominin fire use, the effect of heat on the physical and chemical properties of the materials entering the archaeological record needs to be understood. The present study concerns the fire proxy heated bone. Two types of heating can be distinguished: combustion (or burning, with oxygen) and charring (without oxygen), for both of which the formation of char is the first step. We performed a series of controlled laboratory-based heating experiments, in reducing conditions (i.e. charring), covering a broad temperature range (20–900 °C), and applied a variety of different analytical techniques. Results indicate that charred bone shows a distinctly different thermal alteration trajectory than combusted bone, which has implications for the suitability of the different analytical techniques when identifying and determining past heating conditions (charring vs. combustion; temperature) of heated bone from archaeological contexts. Combined, the reference data and techniques presented in this study can be used as a robust toolkit for the characterisation of archaeological charred bone from various ages and contexts.
Journal of Near Infrared Spectroscopy, 2018
Near infrared spectroscopy and thermogravimetry have been coupled with chemometric exploratory methods in order to investigate ancient (pre-Roman/Roman) human bones from two different necropolises in Central-South Italy (Cavo degli Zucchi and Elea Velia). These findings have been investigated by principal component analysis and they have also been compared with ancient human bones from two Sudanese necropolises (Saggai and Geili). Samples coming from African and European necropolises, mainly differ in two aspects: the burial procedures and their historical period. The ritual applied in the European region involved cremation, while the one applied in the African necropolises did not. Bones from Italian sites (Cavo degli Zucchi and Elea Velia) are Pre-Roman/Roman while the others (from middle Nile) come from the Prehistoric, Meroitic, and Christian Sudanese age. Near infrared spectroscopy and thermogravimetric measures have been analysed either individually or by a mid-level data-fusi...
Applied Clay Science, 2013
Knowing the techniques mastered by ancestors in their production of pottery can help understand their habits and skills, therefore increasing the understanding about their culture. In this work, we study pottery from an archeological site located in the city of Campos dos Goytacazes, state of Rio de Janeiro, Brazil, in order to appraise the firing temperature, atmosphere and time during pottery production. For this purpose, electron paramagnetic resonance spectroscopy (EPR) is used to analyze the signals of iron (Fe 3+). Methods for obtaining the firing temperature were assessed, comparing archeological pottery with clay and changes caused by heat treatment in archeological pottery. In addition, potteries were prepared in laboratory, finding changes in the EPR spectra resulting from changes in the parameters of pottery making. The observation of colors profiles can provide information about temperature, time and firing atmosphere, but it is not accurate. From these findings, it was considered that the archeological pottery studied were prepared in a single firing, at temperatures up to 650°C in an open pit firing with semi-oxidizing atmosphere during a short time of approximately 0.5 h.
V. K. Asfora, P. L. Guzzo, A. M. Pessis, S. Watanabe, H. J. Khoury, 2013
Although the methodology to date pottery and pebbles by thermoluminescence (TL) is based on identical principles, the procedure followed to retrieve the accumulated dose in burnt pebbles offers extra difficulties. In addition, the distinction between burnt and unburnt pebbles is not always free from the subjective influence inherent to the visual inspection. Based on the dependencies of the 110 o C TL peak and the electron paramagnetic resonance (EPR) signal of the E'1 center with the heating temperature of quartz, the aim of this study is to extend the method to classify burnt and un-burnt pebbles independently from visual inspection. For this, several pebbles collected from the East block of the Pedra Furada rock shelter (São Raimundo Nonato, Piauí, Brazil) were used to create a burning pattern assessing TL and EPR responses as a function of the heating temperature. The results showed that the 110 o C peak was not observed in those pebbles that were heated below 400 o C and the intensity of the E'1 signal abruptly decreased with heating above 400 o C. TL and EPR signals of specimens previously classified as "burnt" and "unburnt" appeared in good agreement with the values related to the burning pattern. This method offered the possibility to estimate the temperature in which some pebbles were heated in the past.
Profiling of human burned bones: oxidising versus reducing conditions
Scientific Reports, 2021
Complementary optical and neutron-based vibrational spectroscopy techniques (Infrared, Raman and inelastic neutron scattering) were applied to the study of human bones (femur and humerus) burned simultaneously under either aerobic or anaerobic conditions, in a wide range of temperatures (400 to 1000 °C). This is the first INS study of human skeletal remains heated in an oxygen-deprived atmosphere. Clear differences were observed between both types of samples, namely the absence of hydroxyapatite’s OH vibrational bands in bone burned anaerobically (in unsealed containers), coupled to the presence of cyanamide (NCNH2) and portlandite (Ca(OH)2) in these reductive conditions. These results are expected to allow a better understanding of the heat effect on bone´s constituents in distinct environmental settings, thus contributing for an accurate characterisation of both forensic and archaeological human skeletal remains found in distinct scenarios regarding oxygen availability.
A fragment of an archeological funerary urn from Campos dos Goytacazes, Brazil, was studied using electron paramagnetic resonance (EPR) and X-ray diffraction (XRD). The thermal stability of all paramagnetic species was studied with isothermal treatment. In the present study, the iron signal (Fe 3 + ) cannot be used as a firing temperature reference for archeological pottery. The intensification of this signal with temperature is a consequence of Fe 2 + oxidation, but this reaction occurs in a short-lived treatment at high temperature or in an extended treatment at lower temperature. However, the iron signal and three other paramagnetic species indicate that the urn was fired for an extended time (up to three days). The thermal stability of the three paramagnetic species indicates a firing temperature of around 500 1C in the inner layer, between 400 and 500 1C in the middle layer, and between 500 and 800 1C in the outer layer. The presence of kaolinite structures only in the middle portion is consistent with the temperature values estimated. A firing method for the funerary archeological urn is suggested.
Radiation Measurements, 1998
ÐA modern red deer bone was heated in a mue furnace at increasing temperatures in the range 200 to 9408C. Samples were analyzed by infrared and X-ray diraction spectrometry before measurement of the ESR signals around g = 2.002 by ESR spectrometry. Each sample was irradiated by a gamma source (cobalt-60) at increasing doses in the range 100 to 10 000 Gy. g-irradiated samples were then analyzed by ESR spectrometry in order to obtain the growth curve and to show ESR signal behavior. ESR signals of fossil bones from archaeological deposits of the Lazaret cave (Middle Pleistocene, France) were studied and colors were compared with modern samples in order to assess at which temperature these fossil bones were heated in prehistoric ®replaces.
Journal of Archaeological Science: Reports, 2019
Heated bones are an important part of the material remains within the archaeological record and, among others, can reflect aspects of hominin diet, fuel management and funerary practices. A better understanding of the properties of heated bone potentially provides a better understanding of hominin behaviour and the timing and nature of fire use and control. When bone is heated in a fire, thermal alteration (charring) and oxidation (combustion) processes result in changes of the physical and chemical properties of the bone, depending on the heating intensity (temperature and duration) and oxygen availability. We conducted a series of controlled laboratory based heating experiments (200-900 °C) under oxidising conditions (i.e. combustion) and analysed the samples using a variety of different analytical techniques. Although many studies on the heating of bone exist, these focus just on combusted bone. We, however, are able to directly compare the combustion of bone to the thermal degradation of bone under reducing conditions by applying the same experimental protocol with the same bone material, and similar analytical techniques, as in our previous work on charred bone. This allows us to not only distinguish between bone heated to different temperatures but also to distinguish between bone heated in the presence or absence of air, which might occur, for example, when bone is heated while buried. As bone responds differently to heat in the presence or absence of oxygen, being able to distinguish between both heating conditions is vital in reconstructing the temperature and other heating conditions. Together the reference data and analytical techniques presented in our current and previous study provide the archaeologist with a robust toolkit to determine the temperature and oxygen availability of heated archaeological bone, which will help to reconstruct aspects of hominin fire-related behaviours, including early food processing.