188 research outputs found
Physicochemical changes in bone bioapatite during the late postmortem interval pre- and post-burning
Postmortem chemical transformation of bone bioapatite can take place during early diagenesis resulting in a more thermodynamically stable mineral phase. This paper examines the impact of a 1-year postmortem interval on unburnt and burnt bone’s structural and chemical alterations. This question is of importance for the reconstruction of funerary practices involving cremation in the archaeological record, as well as forensic anthropological investigations. Fleshed pig (Sus scrofa) tibiae were left exposed in a field, then collected at 14, 34, 91, 180, 365-day intervals prior to being burnt in an outdoor fire (≤750 °C bone temperature). Fresh (fleshed) tibiae acted as unburnt and burnt controls. Also included in the study were two cremated human bone fragments from Middle/Late Neolithic (ca. 3300–2500 cal BC) Ireland. Samples were analysed for major and trace elements by wavelength dispersive electron microprobe analyser (EMP-WDS) and molecular structures by Fourier Transform Infrared Spectroscopy (FTIR). Linear regression, PCA, LDA, and MANOVA were performed for statistical analysis. Results indicate that the concentrations of elements associated with extracellular fluid (K, Na, Cl) change with the postmortem interval (PMI) and survive burning. K values under 0.07 ± 0.01 wt% in inner and mid-cortical zones of burnt bones suggest that bones were not burnt immediately after death. Using this criterion, results from the archaeological samples would indicate a PMI of at least weeks to months prior to cremation. Ca, P, Fe, Al, Si, and Sr are not significantly altered with burning, and Fe, Al, Si, Sr are also unaffected by the PMI. In unburnt bones increased crystallinity and carbonate loss are detectable in <1 year, but both are obscured by burning. Structurally, the carbonate to phosphate ratio (C/P), the phosphate high temperature (PHT), and cyanamide to phosphate (CN/P) are the most useful ratios for discriminating between unburnt and burnt bones
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Late Pleistocene paleosol formation in a dynamic aggradational microenvironment - A case study from the Malá nad Hronom loess succession (Slovakia)
The geomorphological characteristics of the loess succession at Malá nad Hronom (Slovakia) mean that it provides a valuable opportunity for the investigation of differences in soil formation in various topographic positions. Along with the semiquantitative characterization of the paleosols (on the basis of physical properties, texture, the characteristics of peds, clay films, horizon boundaries), high-resolution field magnetic susceptibility measurements and sampling were carried out along four different sections of the profile. Samples for luminescence dating were also taken, in order to establish the chronostratigraphical position of the paleosols studied. The comparison of various proxies revealed the differences in soil formation in a dynamic aggradational microenvironment for the same paleosol horizons located in various positions along the slope. Contrary to expectation, paleosols developed in local top or slope topographical positions did not display significant differences in e.g. in their degree of development, nor the characteristics of their magnetic susceptibility curves. In the case of paleosols in positions lower down the slope, signs of quasi-permanent sediment input could be recognized as being present as early as during the formation of the soil itself. This sediment input would seem to be surpassed in the case of pedogenesis strengthened by the climate of the last interglacial (marine isotope stage - MIS 5). Pedogenesis seems to be sustained by renewed intense dust accumulation in the Late Pleistocene, in MIS 3, though compared to MIS 5, the climate of MIS 3 did not favor intense pedogenesis. Despite the general belief that loess series formed in plateau positions can preserve terrestrial records without significant erosion, in the case of the Malá nad Hronom loess this is not so. Compared to the sequence affected by erosional events in the local top position, the sequence affected by quasi-continuous sediment input in the lower slope position seems to have preserved the soil horizons intact.International Visegrad Fund (project Number 11410020). The paper was also supported by a long-term conceptual development subvention available to research organizations RVO: 68145535 from the Institute of Geonics AS CR, by the Slovak Research and Development Agency under contract No. APVV-0625-11 (project “A new synthesis of the Western Carpathians landform evolution – preparation of the database for testing of key hypotheses”. B. Bradák acknowledges the financial support of project BU235P18 (Junta de Castilla y Leon, Spain) and the European Regional Development Fund (ERD), project PID2019-108753GB-C21 / AECI / 10.13039/501100011033 of the Agencia Estatal de Investigación and project PID2019-105796GB-100 / AECI / 10.13039/501100011033 of the Agencia Estatal de Investigación
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