ESR signal behavior study at g∼2.002 of modern and fossil bones for heating palaeotemperature assessment (original) (raw)
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ESR EXPERIMENTS ON QUATERNARY CALCITES AND BONES FOR DATING PURPOSES
A series of experiments and measurements regarding sample preparation, peak intensity estimation, annealing, signal identification, dose determination and dose-rate estimation were carried out in order to explore the technique of ESR for dating speleothemes and bones. In addition, for the first time, the behaviour of peaks at low temperatures (room temperature to 4K) has been studied. Materials from the cave Apidima in Peloponnese, where anthropological remains were discovered, have been used for this study. The results indicate the ~xistenee of four peaks, two organic and two radiation induced. Their intensity is increased at 260K and therefore the sensitivity of the technique is enhanced at lower temperatures. The bone samples were found to have absorbed large amounts of uranium from the environment making their dating impossible. A range of ages 20-45 9 103 years have been calculated for the travertines of the cave, taking into account all possible factors affecting the age.
Q-band esr studies of fossil teeth: Consequences for esr dating
Quaternary Science Reviews, 1988
At least 14 axial-symmetry ESR lines in Plio-Quaternary enamel fibres were observed by Q-band technique. Some lines follow a 1/T law e.g. the main anisotropic A-line whose gi = 2.0018 and gll = 1.9977 are close to ge, = 2.0020 and geff = 1.9975 respectively of the isotropic doublets B-and E-lines. The other lines are blocked below 220K e.g. one isotropic hyperfine (g = 2.0033, a = 21.6 Gauss) M-septet and one isotropic singlet (g = 2.0007) D-line. By heating, the M-septet intensity increases up to 250°C and is lost at 280°C; B-and E-lines decrease while a new isotropic (g = 2.0056) C-line appears. At 300°C, only the two C-and A-lines usually remain and hold up to 400°C.
Using X-Ray As An Irradiation Source For Direct ESR Dating of Fossil Teeth
2021
In this paper we have tested the potential application of X-rays as an irradiation source in Electron Spin Resonance dating of tooth enamel. Both modern and fossil samples were used to assess the feasibility of dose estimations using this alternative irradiator. Equivalent doses obtained with gamma-rays on fossil powder enamel was frequently less than the doses obtained on fragments using only X-rays. It is believed that a combination of NOCORs (non-orientated CO2- radicals) and local internal dose discrepancy may be the origin of the difference. Here, we show that testing penetration attenuation for each individual irradiation source is required to accurately estimate the maximum enamel thickness and produce reliable protocols. The use of a known laboratory additive dose allows the calculation of an absorption equivalent coefficient between gamma-rays and X-rays. We conclude that X-rays are an alternative irradiation source for ESR dating protocols, however, limitations remain in p...
Applied Radiation and Isotopes, 2010
Spectrum decomposition of the angular measurements of fossil tooth enamel fragments using an automated simulated annealing (SA) procedure shows that the mix CO À 2 radicals generated by laboratory irradiation is significantly different to that of the natural sample. The naturally irradiated sample contains about 10% of non-oriented CO À 2 radicals and a mix of 35:65 orthorhombic to axial CO À 2 radicals. In contrast, laboratory irradiation generated about 40% of non-oriented radicals and a large amount of orthorhombic CO À 2 radicals, while we failed to detect any axial CO À 2 radicals. The results indicate that geological aging of the sample incurs various annealing and transfer processes; their precise nature is yet unknown. Nevertheless, the understanding of the formation and transfer processes that leads to the observed mix of CO À 2 radicals in fossil tooth enamel is essential for the reliable application of ESR dating.
Characteristic burn temperature markers of bones as revealed by electron paramagnetic resonance
Heritage science, 2024
This research paper presents a novel methodology for determining the burn temperature of archaeological bones using electron paramagnetic resonance (EPR) supported by Fourier Transform Infrared (FTIR) spectroscopy. A selection of bone samples, burned at different temperatures, were examined with EPR. The EPR spectra displayed dependency on burn temperature, showing characteristic narrow spectra of carbon radicals, Mn 2+ signals and signals from different carbonate ions. This methodology was applied to selected archaeological samples of burnt bones, successfully determining the burn temperature these bones were exposed to in the past. The extracted burn temperatures showed good agreement with those determined from a complementary reflectance FTIR study.
EPR Dating of Hydroxyapatite from Fossil Bones. Transient Effects, after gamma and UV Irradiation
Acta Physica Polonica A, 2006
ESR measurements at room temperature have been performed on fossil bones of cave bear (from Magurska Cave of the Tatra Mountains) and mammoth (from Dniestr River). Various paramagnetic centres related to defects in hydroxyapatite were identified. The ESR spectrum is dominated by Mn2+ lines and free radical centres CO2-, and CO3-. Suitability of various EPR lines for the dating was
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...
Evaluating the Potential of Q-Band ESR Spectroscopy for Dose Reconstruction of Fossil Tooth Enamel
PloS one, 2016
The potential of Q-band Electron Spin Resonance (ESR) for quantitative measurements has been scarcely evaluated in the literature and its application for dose reconstruction of fossil tooth enamel with dating purposes remains still quite unknown. Hence, we have performed a comparative study based on several Early to Middle Pleistocene fossil tooth samples using both X- and Q-band spectroscopies. Our results show that Q-band offers a significant improvement in terms of sensitivity and signal resolution: it allows not only to work with reduced amounts of valuable samples (< 4 mg), but also to identify different components of the main composite ESR signal. However, inherent precision of the ESR intensity measurements at Q-band is clearly lower than that achieved at X-band, highlighting the necessity to carry out repeated measurements. All dose values derived from X- and Q-band are nevertheless systematically consistent at either 1 or 2 sigma. In summary, our results indicate that Q-...
Acta Physica Polonica A - ACTA PHYS POL A, 2006
Natural calcite samples were collected from the dripstone layers of the Black Cave of the Tatra Mountains. ESR spectra, thermal analysis, and thermoluminescence data were analysed to obtain a consistent picture of the calcite properties. The ESR spectra were analysed using computer enhanced resolution spectra and an influence of the thermal annealing on intensity of individual ESR lines was measured. These results together with the effects of gamma-irradiation in ESR spectra allowed one to discriminate between ESR lines from various paramagnetic centres. A general conclusion of the paper is that in the ESR dating the outer ESR lines of CO-3 (g=2.0125) and CO-2 (g=1.9980) radicals should be used instead of the commonly used multicomponent central line.