- Detalles de la revista
- Publicado por primera vez
- 04 Jul 2007
- Periodo de publicación
- 1 tiempo por año
- Acceso abierto
Investigation of lime mortars and plasters from archaeological excavations in Hippos (Israel) using Electron Paramagnetic Resonance
Páginas: 112 - 120
This study presents the preliminary results of investigation of the lime mortars and plasters from archaeological excavations in Hippos (Israel), using Electron Paramagnetic Resonance (EPR) spectroscopy. The research was conducted in order to characterize the building material and its reaction to ionizing radiation. The ancient settlement Hippos, situated on the east shore of the Sea of Galilee, functioned from the 3rd cent. BC until it was destroyed by the earthquake in 749 AD. Lime mortars and plasters show carbonate and locally gypsum character of binder and different kind of aggregate. Samples were γ-irradiated and measured using X-band EPR spectrometer. Computer Resolution Enhancement Method was applied to the complex spectra. Some of the γ-induced EPR signals were attributed to CO2 − and CO3 3− paramagnetic centres. Exponential growth of the dose response curve above 1 kGy and saturation for doses above 20 kGy was observed. For doses lower than 1 kGy the dose response curve has a linear character. The presence of γ-sensitive carbonate paramagnetic centres could indicate that, after further studies, well-chosen samples of mortars and plasters might be suitable for EPR dating, assuming the centres have been sufficiently bleached during the manufacturing process.
- EPR dating
- lime mortars
- lime plasters
- calcium carbonate
- resolution enhancement
- Acceso abierto
Páginas: 121 - 128
Sub-fossil oaks from Smarhoń in Belarus have been investigated and tree-ring chronologies were assembled. According to radiocarbon dating, the oldest oak grew from 5782–5612 cal BC and the youngest from 1575–1747 cal AD. Radiocarbon and dendrochronological dating of 97 samples, four single series, 10 mean curves (containing 2–9 series) and three chronologies (10–25 series) were constructed. The longest chronology (No. 16), covering 549 years, was absolutely dated against various oak chronologies of Polish/Baltic origin to AD 778–1326. Germination and dying-off phases were assessed from the three best replicated chronologies. A spectral analysis of the chronologies provided cycles of variable length, on average of 25 years.
- sub-fossil oak
- tree-ring widths
- Acceso abierto
The application of the tree-ring chronologies in assessing ecological requirements of Metasequoia glyptostroboides growing in southern Poland
Páginas: 129 - 135
Metasequoia glyptostroboides is considered to be a species highly resistant to harmful environmental factors. For this reason it has been introduced to the cities. The climate of Krakow differs from that in its natural range in China. The research was focused on 40-year-old trees, planted in Kraków on fertile alluvial soils with a low level of ground water, in the vicinity of the steelworks. During the period of the highest level of air pollution in the 1970s and 1980s, the radial increment of investigated trees showed an increasing trend. At the end of the 1980s, when the emissions were reduced, a decreasing trend in radial growth was recorded. Throughout the entire period of their life the investi-gated trees have shown high homogeneity of short-term growth reactions. The sensitivity chronology of the trees was characterized by a high representativeness and a strong high-frequency signal. This may indicate that the investigated trees have shown a large sensitivity to climatic factors.
The positive effect on the radial growth of Metasequoia had a cold September in the previous year, and also a cold January, April and May in the year of ring formation. Positive impact on the growth of trees had also the high precipitation occurring in April and August, as well as high air humidity in the spring of the year of ring formation. In the period 1974–2011 fifteen signature years were found. The analysis of the climatic conditions in these years confirms the results of the statistical analyses.
- Metasequoia glyptostroboides
- Acceso abierto
Evaluating similarity of radial increments around tree stem circumference of European beech and Norway spruce from Central Europe
Páginas: 136 - 146
Extracting cores from a tree using an increment borer has been standard practice in dendrochronological studies for a long time. Although empirical rules exist regarding how many samples to take and which methodology to apply, comparatively few studies provide quantification of the similarity of relative tree-ring-widths (TRW) around the stem circumference. The aim of this study was therefore to precisely measure the similarity of standardised TRWs around the stem circumference and to provide objective suggestions for optimal core sampling of Norway spruce (Picea abies Karst. [L.]) and European beech (Fagus sylvatica L.) growing in Central European temperate forests.
A large sample of cross-sectional discs was used from Norway spruce and European beech trees growing on various slopes, at different altitudes and biogeographic regions across the Czech Republic and Slovakia. The similarity of TRWs measured in different coring directions was analysed by testing the relativized TRW around the trunk (rTRW). Comparison of rTRWs revealed no significant differences between coring directions, indicating that the relative increment was the same around the radius. The results also showed the high similarity between the rTRWs to be independent of both slope inclination and altitude. Moreover, the reconstruction of proportional tree diameters and basal areas backward in time from one core sample and one measurement of tree diameter (basal area) at the time of sample extraction is possible with reasonable precision.
- relative tree-ring width
- basal area reconstruction
- core sampling
- Acceso abierto
Páginas: 147 - 159
The oxygen isotope ratio (δ18O) in tissues is the outcome of both climatic and geographical factors in a given individual’s place of abode, as well as the physiology and metabolism of his organism. During an individual’s life, various rates and intensities of physiological and metabolic processes are observable in the organism, also within the bone tissue.
The aim of this study is to verify whether involutional changes occurring as a result of the organism’s ageing have a significant impact on δ18O determined in the bone tissue.
The material used for analysis was fragments of the long bones taken from 65 people, (11 children and 54 adults), whose remains had been uncovered at the early mediaeval (X–XI century) cemetery located at the Main Market Square in Kraków (Poland).
The correlation analysis between δ18O of bone tissue and an individual’s age shows that up to 40 years of age, such a relationship does not exist in both, males and females. However, the conducted correlation analysis prompted the observation that after 40 years of life, δ18O in bone tissue significantly drops as females increase in age.
Results suggest that the δ18O in bone tissue among older people may be the outcome not only of environmental factors but also involutional changes in bone linked to an organism’s ageing. Therefore, the interpretation of δ18O results relating to the description of the origin and migrations of older individuals should be treated with caution.
- oxygen isotopes
- human remains
- Acceso abierto
Páginas: 160 - 167
The so-called thermal “cleaning” applied in thermoluminescence analysis allows distinguishing TL signal originating from different traps of comparable thermal depths. Here, the detailed study on the suitability of a similar approach — which can be called optical “cleaning” — for the analysis of OSL process has been carried out by means of computer modelling. The optical “cleaning” is realized by short optical stimulation applied directly after irradiation. It turns out that this approach does not help to separate signals related to various traps having similar optical cross-section (OCS) values. For some sets of trap parameters, sufficiently good reconstruction of the trap optical cross-sections can be achieved by the analysis of the conventional OSL curve obtained directly after sample irradiation, while the OSL curve analysis after “cleaning” does not provide any additional data. For other cases the analysis of both curves with and without “cleaning” leads to optical cross-section values different from those assumed in the model, but just in such situations the optical “cleaning” can be helpful. The differences between the OSL components of the conventional curve and the one obtained after “cleaning” can be used as indicators of an incompatibility of the trap parameters obtained from the OSL analysis with their actual values.
- optically stimulated luminescence
- optical cross sections
- Acceso abierto
Kinetic analysis of thermoluminescence glow curves in feldspar: evidence for a continuous distribution of energies
Páginas: 168 - 177
The thermoluminescence (TL) glow curves from feldspars have been the subject of numerous studies, because of their importance in luminescence dating and dosimetry. This paper presents new experimental TL glow curves in a plagioclase feldspar, measured using the T max-T stop technique of glow curve analysis. Kinetic analysis of the experimental results is carried out for a freshly irradiated sample, as well as for a sample which has undergone optical treatment using infrared light for 100 s at 50°C. Application of the initial rise method of analysis indicates that the TL signals from both samples can be characterized by a continuous distribution of energy levels. By subtracting the TL glow curves measured at successive T stop values, a series of TL glow curves is obtained which are analyzed using the empirical general order kinetics. It is found that all TL glow curves obtained by this subtractive procedure can be described accurately by the same general order parameter b ∼1.7. In a second attempt to analyze the same TL glow curves and possibly extract information about the underlying luminescence process, the shape of TL glow curves is analyzed using a recently proposed physical kinetic model which describes localized electronic recombination in donor-acceptor pairs. Within this model, recombination is assumed to take place via the excited state of the donor, and nearest-neighbor recombinations take place within a random distribution of centers. This recent model has been used recently to describe successfully several types of luminescence signals. This paper shows that it is possible to obtain good fits to the experimental data using either one of these two approaches.
- thermoluminescence in feldspars
- kinetic analysis
- feldspar glow curves
- random defect distribution