Carbon and oxygen isotope measurements (δ13C, δ18O) of bioapatite carbonate fractions in archaeological and fossil remains are essential tools to investigate past diets and climates. The reliability ...of these reconstructions is however dependent on the recovery of the biological signal and the removal of competing sources of carbon and oxygen isotopes, such as remaining organic material and secondary carbonates. Modern, archaeological and fossil bone and tooth specimens have been treated with different chemicals commonly used to pre-treat the samples with the aim of removing these competing sources of isotopes. Results highlight significant shifts in the isotope values of the samples tested, with different isotopic effects according to which pre-treatment was used. This has a clear impact on the data recovered, and may lead to misinterpretations of the results and inferred past diets and climates. The results of this study suggest that both hydrogen peroxide and sodium hypochlorite, the most commonly used oxidising agents employed to remove organic substance, have major problems: hydrogen peroxide is only partially efficient as organic removal agent and causes unwanted bioapatite dissolutions and isotopic shift, while sodium hypochlorite induces the incorporation of exogenous carbonates into the bioapatite, likely from the dissolution of atmospheric CO2 into the test tube. In both cases, there is an impact on the recovered isotope composition. Hydrazine hydrate, a third chemical for organic removal, has the lowest influence on the bioapatite isotopic composition, being also efficient at removing organic matter from bioapatites. The latter is recommended as an organic removal agent if such pre-treatment is deemed necessary. The use of acetic acid also causes isotopic shifts that seem independent on the removal of secondary/diagenetic carbonate, as also occurring in modern samples. Overall, our study clearly shows that any chemical treatment commonly used to remove unwanted contaminants from the bioapatite samples has also unpredictable, often significant effects on the pristine isotopic composition recovered, and corroborates the need for consistency in the pre-treatment of bone and teeth specimens. It also questions the necessity of removing organic matter at all from most skeletal samples prior to isotopic analysis.
•Effects and efficiency of the most common skeletal apatite pre-treatment chemicals were tested.•All the chemicals tested determine some isotopic shift that seems not to be only related to the removal of organic matter.•H2O2 partly dissolves the carbonate fraction of bioapatite, while being not effective at removing organic substance.•NaClO is efficient at removing organics but induces the adsorption of atmospheric CO2 and the precipitation of carbonate.•N2H4·H2O (hydrazine) is efficient at removing organic matter and causes the smallest C and O isotopic shifts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Vitamin D deficiency has hugely impacted the health of past societies. Its identification in skeletal remains provides insights into the daily activities, cultural habits, and the disease load of ...past populations. However, up till now, this approach remained impossible in cremated bones, because temperatures reached during cremations destroyed all macroscopic evidence of vitamin D deficiency. This precluded the analyses of a large fraction of the archaeological record, as cremation was an important burial ritual from the Late Neolithic until the Early Medieval period in Europe. Here, the identification of interglobular dentine (IGD), a dental mineralisation defect attributed to vitamin D deficiency, in experimentally burnt teeth, demonstrates this deficiency to be observable in human teeth burned to temperatures as high as 900 °C. In most cases, it becomes even possible to assess the ages-of-occurrence as well as the severity of the IGD and possibly vitamin D deficiency intensity. This study represents a major step forward in the fields of biological anthropology, archaeology, and palaeopathology by opening up a variety of new possibilities for the study of health and activities related to sunlight exposure of numerous past populations that practiced cremation as their funerary ritual.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The adsorption of phosphate on hydrated ferric oxide (HFO) was studied in solutions containing major seawater ions (Na+, Mg2+, Cl−, SO42−, Ca2+, K+) at pHs 6.5, 7.5 and 8.5. The presence of these ...ions promotes phosphate adsorption and the process is electrostatic in nature. Despite this electrostatic force, the precipitation of hydroxyapatite in the presence of Ca2+ at pH 8.5 also plays an important role in the removal of phosphates from the dissolved phase. Energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FTIR) spectra support that phosphate adsorption on HFO surface can be attributed to inner sphere complexes with the formation of bidentate complexes (FeO)2PO2 in the presence of main seawater ions at pH = 8.5. The results of EDS clearly indicated that Fe-P-Ca complexes, Fe-P-Mg, or other phosphate-bridged ternary complexes were not formed during adsorption in the presence of NaCl, KCl, CaCl2, Na2SO4 and MgCl2. This observation differs somewhat from that the typical explanation used to describe the phosphate adsorption mechanism on HFO. The CD-MUSIC model makes it possible to describe this adsorption mechanism of phosphate on HFO in the presence of 0.7 M NaCl, and these outcomes are coherent with the experimental FTIR and EDS results.
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•Phosphate adsorption on HFO is promoted by seawater ions through electrostatic interactions.•Inner-sphere complexation occurs leading to the formation of (FeO)2PO2.•No phosphate-bridged ternary complexes such as Fe-P-Ca or Fe-P-Mg are formed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study presents a methodological advancement in the field of clumped‐isotope (∆47) thermometry, specifically tailored for application to freshwater ostracods. The novel ostracod clumped isotope ...approach enables quantitative temperature and hydrological reconstruction in lacustrine records. The relationship between ∆47 and the temperature at which ostracod shell mineralized is determined by measuring ∆47 on different species grown under controlled temperatures, ranging from 4 ± 0.8 to 23 ± 0.5ºC. The excellent agreement between the presented ∆47 ostracod data and the monitored temperatures confirms that ∆47 can be applied to ostracod shells and that a vital effect is absent outside the uncertainty of measurements. Results are consistent with the carbonate clumped‐isotope unified calibration (Anderson et al., 2021, https://doi.org/10.1029/2020gl092069), therefore, an ostracod‐specific calibration is not needed. The ostracod clumped‐isotope thermometer represents a powerful tool for terrestrial paleoclimate studies all around the world, as lakes and ostracods are found in all climatic belts.
Plain Language Summary
In the framework of global warming, the reconstruction of past climatic conditions is important to understand the future evolution of climate and its impact. Lake sediments can be used as archives to quantify these effects. This study presents a novel paleo‐thermometer based on the application of clumped‐isotope technique (i.e., measurement of the number of 13C–18O bonds in carbonate minerals that depends on the temperature of carbonate precipitation) on carbonatic microcrustacea, named ostracods that commonly live in lakes. By using ostracods that formed their shells at known temperatures, we demonstrate that they can be easily used to reconstruct water temperature and hydrological conditions (precipitation/evaporation). The ostracod clumped‐isotope thermometer represents a powerful tool for terrestrial paleoclimate studies around the world, as lakes and ostracods are located in all climatic belts.
Key Points
∆47—ostracod signal accurately records the shell calcification temperature
∆47—ostracod signal is not affected by the so called “vital effect”
The unified calibration of Anderson et al. (2021) can be used to convert the ∆47—ostracod signal into accurate temperatures
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The distribution of the first domesticated animals and crops along the coastal area of Atlantic NW Europe, which triggered the transition from a hunter-gatherer-fisher to a farmer-herder economy, has ...been debated for many decades among archaeologists. While some advocate a gradual transition in which indigenous hunter-gatherers from the very beginning of the 5th millennium cal BC progressively adopted Neolithic commodities, others are more in favor of a rapid transition near the end of the 5th millennium caused by a further northwest migration of farmers-herders colonizing the lowlands. Here, radiocarbon dated bones from sheep/goat and possibly also cattle are presented which provide the first hard evidence of an early introduction of domesticated animals within a hunter-gatherer context in NW Belgium, situated ca. 80 km north of the agro-pastoral frontier. Based on their isotope signal it is suggested that these first domesticates were probably not merely obtained through exchange with contemporaneous farmers but were kept locally, providing evidence of small-scale local stockbreeding in the lowlands maybe as early as ca. 4800/4600 cal BC. If confirmed by future in-depth isotope analyses, the latter testifies of intense contact and transmission of knowledge in this early contact period, which is also visible in the material culture, such as the lithic and pottery technology. It also implies direct and prolonged involvement of farmer-herders, either through visiting specialists or intermarriage, which follows recent genetic evidence demonstrating much more hunter-gatherer ancestry in early farmer's genes in western Europe compared to central and SE Europe.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The barrow cemetery at Heath Wood, Derbyshire, is the only known Viking cremation cemetery in the British Isles. It dates to the late ninth century and is associated with the over-wintering of the ...Viking Great Army at nearby Repton in AD 873-4. Only the cremated remains of three humans and of a few animals are still available for research. Using strontium content and isotope ratios of these three people and three animals-a horse, a dog and a possible pig-this paper investigates the individuals' residential origins. The results demonstrate that strontium isotope ratios of one of the adults and the non-adult are compatible with a local origin, while the other adult and all three animals are not. In conjunction with the archaeological context, the strontium isotope ratios indicate that these individuals most likely originated from the area of the Baltic Shield-and that they died soon after arrival in Britain. This discovery constitutes the first solid scientific evidence that Scandinavians crossed the North Sea with horses, dogs and other animals as early as the ninth century AD.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To achieve a reliable radiocarbon (14C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as ...adhesives, varnishes or consolidants can pose a particular challenge to 14C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called Chromosorb® was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable 14C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives.
Burial rites of archaeological populations are frequently interpreted based on cremated remains of the human body and the urn they were deposited in. In comparison to inhumations, information about ...the deceased is much more limited and dependent on fragmentation, selection of body regions, taphonomic processes, and excavation techniques. So far, little attention has been paid to the context in which urns are buried. In this study, we combined archaeological techniques with anthropology, computed tomography, archaeobotany, zooarchaeology, geochemistry and isotopic approaches and conducted a detailed analysis on a case study of two Late Bronze Age urns from St. Pölten, Austria (c. 1430 and 1260 cal. BCE). The urns were recovered en-bloc and CT-scanned before the micro-excavation. Osteological and strontium isotope analysis revealed that the cremated remains comprised a young adult female and a child that died at the age of 10-12 years. Both individuals had been subject to physiological stress and were likely local. Animal bones burnt at different temperatures suggested different depositional pathways into the urn and pit as part of the pyre, food offerings, and unintentional settlement debris. Eight wild plant and five crop plant species appeared as part of the local landscape, as food offerings and fire accelerants. Sediment chemistry suggests that pyre remains were deposited around the urns during burial. Multi-element geochemistry, archaeobotany, and zooarchaeology provide insights into the Late Bronze Age environment, the process of cremation, the gathering of bones and final funerary deposition.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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