Search

AbstractThe present paper compile and correlate for the first time Cretaceous to Eocene palynostratigraphies across the Arctic. It focus on Greenland and adjacent areas, including the Labrador–Baffin Seaway, onshore Nuussuaq Basin in central West Greenland, onshore southern East Greenland, central East Greenland, North-East Greenland, eastern North Greenland and the Danmarkshavn Basin, but also extends to Canadian Arctic Archipelago and the Barents Sea region off Norway. The paper compile data from more than three decades of detailed Arctic palynological analyses, based mainly on dinoflagellate cysts. The paper gives a historical overview of the Cretaceous to Palaeogene paleontological studies of Greenland and presents an overview of 85 palynological intervals and numerous events. The palynological assemblages from the Labrador–Baffin Seaway, Nuussuaq Basin and north-east Baffin Bay reflect the opening of the Labrador–Baffin Seaway from brackish to freshwater environment in a large embayment in the Early Cretaceous to an open marine seaway in the Late Cretaceous. Assemblages reveal in dinoflagellate cyst provincialism between the opening stages of the Labrador–Baffin Seaway and the already opened Greenland–Norwegian–Barents seaway. The Upper Cretaceous global Oceanic Anoxic Event 2 (OAE2) spanning the Cenomanian/Turonian boundary is recognised from Arctic Canada, north-east Baffin Bay, Nuussuaq Basin in central West Greenland, and North-East Greenland, and is mapped and correlated based on dinoflagellate cyst stratigraphy and carbon isotope (δ13Corg) curves. The dinoflagellate cysts assemblages of the Cretaceous/Palaeogene boundary are correlated from the Labrador Sea across to the Nuussuaq Basin in central West Greenland; in both areas the earliest Danian palynological assemblage is represented by incoming warm-water species. The presence of the global Paleocene–Eocene Thermal Maximum (PETM) in the Palaeogene successions in North-East Greenland and in exploration wells in the Labrador–Baffin Seaway is indicated by the incoming of the warm-water dinoflagellate cyst species Axiodinium augustum. [ABSTRACT FROM AUTHOR]

The recently published Lethaia paper by Bergström et al. (https://doi.org/10.1111/let.12269) on the age of the Ordovician Winneshiek Shale (Iowa, USA), and the impact that formed the Decorah crater which hosts this rock unit, is an interesting scientific contribution, although there are a number of problems with the interpretations and data presentation that merit comment. Due mainly to a lack of adequate critical assessment of δ13C data and biostratigraphical control, we contend that the conclusions of Bergström et al. are poorly founded and should not be cursorily accepted and propagated in future scientific literature. [ABSTRACT FROM AUTHOR]

When undertaking any study of the isotope abundance values of a bulk material, consideration should be given to the source materials and how they are combined to reach the final product being measured. While it is demonstrative to measure and record the values of clean papers, such as the results published as part one of this series, the majority of forensic casework samples would have undergone some form of writing or printing process prior to examination. Understanding the effects of these processes on the δ13C values of paper is essential for interpretation and comparison with clean samples, for example in cases where printed documents need to be compared to paper from an unprinted suspect ream. This study was undertaken so that the source materials, the effects of the production process and the effects of printing and forensic testing could be observed with respect to 80 gsm white office papers. Samples were taken sequentially from the paper production facility at the Australian Paper Mill (Maryvale, VIC). These samples ranged from raw wood chips through the pulping, whitening and refinement steps to the final formed and packed paper. Cellulose was extracted from each sample to observe both fractionation and mixing steps and their effect on the δ13C values. Overall, the mixing steps were observed to have a larger effect on the isotopic values of the bulk materials than any potential fractionation. Printing of papers using toner and inkjet printing processes and forensic testing were observed to have little effect on δ13C. These experiments highlighted considerations for sampling and confirmed the need for a holistic understanding of sample history to inform the interpretation of results. [ABSTRACT FROM AUTHOR]

Urbanization and the release of carbon emission are two significant features of contemporary economic and social progress in China. However, there are few studies that consider how urbanization policy goals affect carbon emission. This paper aims to study the nonlinear effects of urbanization policy goals on carbon emission in 13 cities of the Beijing-Tianjin-Hebei region. In this paper, a multi-dimensional spatial disturbance grey model is proposed. Based on matrix perturbation theory, this paper explores the spatial perturbation bounds of the novel model and verifies that the spatial property of the model is consistent with the viewpoint of the First Law of Geography. Then, the novel model is used to predict the urban carbon emission under different urbanization policy goal scenarios. The results showed that the novel model has spatial regional correlation in spatial region prediction. With the development of urbanization level, carbon emissions show a downward trend in more than 50% of cities from 2022 to 2025. In addition, the improvement of urbanization policy goals will promote the carbon peak time of most cities. The carbon emission intensity will exhibit an inverted U-shaped trend distribution in space. The research results are conducive to providing scientific guidance for the formulation of new-type urbanization policies and helping to achieve the dual carbon goals. • A multi-dimensional spatial disturbance grey model is proposed. • The novel grey model is consistent with the viewpoint of the First Law of Geography. • The spatial distribution of carbon intensity showed an inverted U-shaped pattern. [ABSTRACT FROM AUTHOR]

Summary: Diachronic research of social status differences in diet reveals a dynamic interplay of cultural, economic, and technological forces that have shaped the food choices of individuals across the past centuries. In this paper we focus on food and related practices at Palatial Knossos on Crete in the mid‐second millennium BC and review palaeodietary stable carbon and nitrogen isotope (δ13C and δ15N) data from two cemeteries to explore evidence for embodied social variation during the site's uncontested heyday in the Neo‐palatial Period (c.1700 to 1500 BC). We show that analysis by sex and tomb suggests no significant social differentiation in access to food resources. Instead, temporal trends reveal increased availability of animal protein during the Neo‐palatial period, aligning with Knossos' political and economic supremacy. We argue that the equitable living circumstances at Knossos during the Neo‐palatial period may have contributed to the absence of factional competition and social unrest, potentially explaining the site's continuity into Post‐palatial times despite widespread destructions elsewhere on Crete. Overall, the findings shed light on the complex interplay between diet, social structure, and historical context at Neo‐palatial Knossos. [ABSTRACT FROM AUTHOR]

The exploration of continental shale oil in China has made a breakthrough in many basins, but the pure shale type has only been found in the Qingshankou Formation, Gulong Sag, Songliao Basin, and the evaluation of shale oil occurrence and sweet spot faces great challenges. Using information about the total organic carbon (TOC), Rock-Eval pyrolysis, vitrinite reflectance (Ro), kerogen elemental composition, carbon isotopes, gas chromatography (GC), bitumen extraction, and component separation, this paper systematically studies the organic geochemical characteristics and shale oil occurrence at the Qingshankou Formation. The G1 well, which was cored through the entire section of the Qingshankou Formation in the Gulong Sag, was the object of this study. On this basis, the favorable sweet spots for shale oil exploration are predicted. It is concluded that the shale of the Qingshankou Formation has high organic heterogeneity in terms of organic matter features. The TOC content of the source rocks in the Qingshankou Formation is enhanced with the increase in the burial depth, and the corresponding organic matter types gradually changed from Ⅱ2 and Ⅱ1 types to the Ⅰ type. The distribution of Ro ranges from 1.09% to 1.67%, and it is the mature to high-mature evolution stage that generates a large amount of normal crude oil and gas condensate. The high-quality source rocks of good to excellent grade are mainly distributed in the Qing 1 member and the lower part of the Qing 2 member. After the recovery of light hydrocarbons and the correction of pyrolytic heavy soluble hydrocarbons, it is concluded that the occurrence state of shale oil in the Qingshankou Formation is mainly the free-state form, with an average value of 6.9 mg/g, and there is four times as much free oil as adsorbed oil. The oil saturation index (OSI), mobile hydrocarbon content, Ro, and TOC were selected to establish the geochemical evaluation criteria for shale oil sweet spots in the Qingshankou Formation. The evaluation results show that interval 3 and interval 5 of the Qingshankou Formation in the G1 well are the most favorable sections for shale oil exploration. [ABSTRACT FROM AUTHOR]

A new approach is presented in this paper for the dynamic modeling of the chemical and isotopic evolution of C1–3 during the hydrocarbon generation process. Based on systematic data obtained from published papers for the pyrolysis of various hydrocarbon sources (type I kerogen/source rock, type II kerogen/source rock, type III kerogen/source rock, crude oil, and asphalt, etc.), the empirical evolution framework of the chemical and isotopic composition of C1–3 during the hydrocarbon generation process was built. Although the empirical framework was built only by fitting a large amount of pyrolysis data, the chemical and isotopic composition of C1–3 derived from the pyrolysis experiments all follow evolution laws, convincing us that it is applicable to the thermal evolution process of various hydrocarbon sources. Based on the simplified formula of the isotopic composition of mixed natural gas at different maturities (δ13Cmixed), δ13Cmixed = X × n i A × δ 13 C i A + Y × n i B × δ 13 C i B X × n i A + Y × n i B , it can be derived that the cumulative isotopic composition of alkane generated in a certain maturity interval can be expressed by the integral of the product of the instantaneous isotopic composition and instantaneous yield at a certain maturity point, and then divided by the cumulative yield of alkane generated in the corresponding maturity interval. Thus, the cumulative isotopic composition (A(X)), cumulative yield (B(X)), instantaneous isotope (C(X)), and instantaneous yield (D(x)) in the dynamic model, comply with the following formula during the maturity interval of (X0~X). A(X) = ∫ X 0 X C X × D X d x B (X) , where A(X) and B(X) can be obtained by the fitting of pyrolysis data, and D(x) can also be obtained from the derivation of B(X). The dynamic model was applied on the pyrolysis data of Pingliang Shale to illustrate the quantitative evolution of the cumulative yield, instantaneous yield, cumulative isotope, and instantaneous isotope of C1–3 with increasing maturity. The dynamic model can quantify the yield of methane, ethane, and propane, as well as δ13C1, δ13C2, and δ13C3, respectively, during the hydrocarbon generation process. This model is of great significance for evaluating the natural gas resources of hydrocarbon source rock of different maturities and for identifying the origin and evolutionary process of hydrocarbons by chemical and isotopic data. Moreover, this model provides an approach to study the dynamic evolution of the isotope series of C1–3 (including reversed isotopic series), which is promising for revealing the mechanism responsible for isotopic reversal when combined with post-generation studies. [ABSTRACT FROM AUTHOR]

Isotope Ratio Mass Spectrometry (IRMS) has been shown to be a useful tool in the comparison of materials that are chemically identical either through man-made production processes or for materials that have been naturally produced. Paper therefore, is an ideal material for this type of measurement given that it is manufactured from a naturally produced product that can be difficult to discriminate based on physical feature comparison alone. To determine whether carbon isotopes are useful for discriminating document papers, 125 samples from Australia and New Zealand were collected over a 24- month period. When measured, a range of 8‰ was observed. A homogeneity study was undertaken to examine the range of values expected from paper sources including single sheets, single reams and multiple reams from the same brand. These results can also be used to suggest how best to sample from these different sources. After characterizing the natural variation of the material, a range of 1‰ was defined for use as a benchmark for discrimination. Utilizing this threshold, 68% of the 125 collected samples (when paired against each other) could be discriminated using the carbon isotope abundances alone. Additionally, correlation was observed when measured values were plotted against their production region of origin. [ABSTRACT FROM AUTHOR]

This paper describes the development and validation of a method for the analysis of office papers by measuring carbon isotopes using isotope ratio mass spectrometry (IRMS). The method development phase included testing protocols for storage, sample materials, set-up of the analytical run; and examining the effects of other paper examination procedures on IRMS results. A method validation was performed so that the Deltaplus XP IRMS instrument (Thermo Finnigan, Bremen, Germany) with Flash EA™ 1112 could be used to measure document paper samples for forensic casework. A validation protocol that would meet international standards for laboratory accreditation (international standard ISO 17025) was structured so that the instruments performance characteristics could be observed. All performance characteristics measured were found to be within an acceptable range and an expanded measurement uncertainty for the measurement of carbon isotopes in paper was calculated at 0.26‰, with a coverage factor of 2. This method was utilized in a large-scale study, published as part one of this series, that showed that IRMS of document papers is useful as a chemical comparison technique for 80 gsm white office papers. [ABSTRACT FROM AUTHOR]

Calcareous interbeds control the migration of oil and water in marine strata. However, in China, the origins of such calcareous interbeds have not been investigated in detail. In this paper, we present a study of calcareous interbeds in marine strata of the Zhujiang Formation in the Wenchang Oil Field, which is located in the southeast of Hainan Province, China. The lithological characteristics, types and features of diagenesis, and formation of the calcareous interbeds were investigated using core, thin-section, scanning electron microscopy, and cathodoluminescence observations, and stable carbon and oxygen isotope data. The calcareous interbeds consist of mixed sediments, which are dominated by bioclastic limestones containing terrigenous clasts, along with subordinate calcareous sandstone. The interbeds are densely cemented. The bioclasts are dominantly brachiopods, pleopods, and foraminifera, with minor amounts of echinodermata, bivalves, red algae, ostracods, and bryozoa. Diagenesis involved calcitic cementation, associated with relatively weak compaction. Carbon and oxygen isotopic data indicate the pore water that formed the carbonate cement was mostly sourced from seawater and minor amounts of meteoric water. The degree of carbonate cementation was significantly related to the bioclast content. On the basis of our study, a genetic model for the macroscopic and microscopic formation of calcareous interbeds is proposed. [ABSTRACT FROM AUTHOR]

Carbon peaking and carbon neutrality will be important policies to constrain China's economic and social development in the future. Based on the theory of computable general equilibrium, CGE model of carbon emission was constructed in this paper to simulate the influence of different scenarios of carbon emission reduction on economic and social development. The major contribution is to subdivide the energy sector according to primary energy and secondary energy, and construct the macro SAM table and micro SAM table of 21 energy sectors in 2017 to quantitatively simulate the impact of carbon emission reduction policies on China's economy and society, and put forward some policy suggestions based on this. [ABSTRACT FROM AUTHOR]

This paper discusses recent archaeological fieldwork conducted at El Castillejo, a medieval Islamic settlement in Los Guájares, Granada, southern Spain. Results from combined archaeological excavation and archaeoseismological assessment of standing structures suggest that the site was affected by a destructive earthquake during its occupation. Radiocarbon samples and OSL analysis point to a seismic event in the period CE 1224–1266. The earthquake occurred within an area marked by a 'seismological gap' in terms of historic seismicity and the causative fault has been tentatively identified in the Nigüelas-Padul Fault System which lies north of the settlement. This event is not recorded by national or European seismic catalogues and represents the oldest historic earthquake in the Granada area. Our work stresses the significant impact that targeted archaeological investigations can generate in our understanding of the local historic seismicity, thus providing clear implications for seismic disaster prevention and reduction. [ABSTRACT FROM AUTHOR]

This paper presents a study of both the elastic and inelastic scattering of a deuteron beam on 13 C at laboratory energy of 18 MeV. The first 10 excited states of the carbon isotope were studied in terms of single-particle and collective models of excitation. Experimental cross sections were obtained by the well-known Δ E–E method. Elastic scattering data were analyzed using an optical model including a nucleus–nucleus interaction potential, while inelastic scattering data were processed using the coupled-channels approach. For the single-particle model, the spectroscopic amplitudes were obtained through calculations of the large-scale shell model with the YSOXT effective NN-potential. A double folding potential was obtained for the d + 13 C system. A comparison of model calculations with the experimental cross sections was demonstrated. The extracted deformation parameters and calculated spectroscopic information are shown in tables. The ability of the collective model to describe all excited states was demonstrated by good agreement when comparing the calculated cross sections in the collective model and experimental data. The single-particle model turned out to be significant only for the excited state of 3.09 MeV. The dominant role in the formation of the corresponding cross section is played by the 12 C ground state core with the 2 S 1 / 2 neutron. [ABSTRACT FROM AUTHOR]

The spatiotemporal coupling relationship between deep hydrocarbon fluid and sandstone uranium mineralization within the shallow buried red‐variegated clastic rocks in the Qianjiadian area of the Songliao Basin remains a topic of controversy. This paper aims to provide a comprehensive understanding of the source, nature and exudative age of deep exotic hydrocarbon, as well as the interaction mechanism and alteration process between hydrocarbon fluid and clastic rock. To achieve this, various methods were employed, including acidolysis hydrocarbon test (AHT), clay x‐ray diffraction (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), carbon isotope analysis (CIA) and LA‐ICP‐MS U–Pb isotopic dating. The results indicate that some tight sandstones from the Qingshankou Formation in Dalin uranium deposit exhibit high acidolysis hydrocarbon content (AHC), reaching n × 104 μL/kg, and predominantly consisting of low mature oil‐type gas. Local microscopic observations reveal pore fluorescence and hydrocarbon‐bearing inclusions with nattier blue tone. Furthermore, the kaolinites present in the ore area's sand‐bodies show a significantly higher content anomaly, commonly exceeding >50%, compared to the same layer in peripheral regions. Extensive dissolutions of lithic grains and feldspars are observed, along with the widespread occurrence of ferro‐dolomites and colloidal pyrites. Additionally, exotic asphaltenes are sporadically developed in localized areas. These findings provide evidence that the sand‐bodies experienced a significant exfiltration event of external gaseous fluids. The light carbon isotopes (δ13CV‐PDB ranging from −33.26‰ to −30.06‰) of group components and n‐Alkane suggest that the hydrocarbon originates from the source rock of the Lower Cretaceous Jiufotang Formation. A detailed two‐stage alteration sequence caused by acidic and reducing hydrocarbon is clarified, encompassing acidic corrosion, kaolinization, pyritization, silification and asphaltization during the exudation stage, followed by ferro‐dolomitization in the later cessation stage. Notably, vermicular secondary kaolinites, formed through the interaction between acidic hydrocarbon fluid and low‐temperature meteoric groundwater, serve as significant markers for the exfiltration of deep hydrocarbon fluid. In‐situ U–Pb dating of hydrocarbon‐bearing ferro‐dolomite yielded absolute exfiltration ages of 63.54 ± 4.13 and 65.93 ± 3.35 Ma. By integrating the tectonic–sedimentary–fluid evolution history and uranium mineralization characteristics in the study area, a three‐stage superimposed metallogenic model is proposed for the Upper Cretaceous red‐variegated layers: (1) the sedimentary and diagenetic stage of the target layer during the Late Cretaceous, (2) the predominant hydrocarbon exudation stage at the end of the Late Cretaceous, and (3) the main uranium mineralization stage since the Paleogene. This study enhances our understanding of coupled‐genetic sandstone‐type uranium deposit in a sedimentary basin and provides valuable guidance for prospecting similar red‐variegated beds in the Songliao Basin and other sedimentary basins worldwide. [ABSTRACT FROM AUTHOR]

This paper reports a high-resolution isotopic study of medieval horse mobility, revealing their origins and in-life mobility both regionally and internationally. The animals were found in an unusual horse cemetery site found within the City of Westminster, London, England. Enamel strontium, oxygen, and carbon isotope analysis of 15 individuals provides information about likely place of birth, diet, and mobility during the first approximately 5 years of life. Results show that at least seven horses originated outside of Britain in relatively cold climates, potentially in Scandinavia or the Western Alps. Ancient DNA sexing data indicate no consistent sex-specific mobility patterning, although three of the five females came from exceptionally highly radiogenic regions. Another female with low mobility is suggested to be a sedentary broodmare. Our results provide direct and unprecedented evidence for a variety of horse movement and trading practices in the Middle Ages and highlight the importance of international trade in securing high-quality horses for medieval London elites. [ABSTRACT FROM AUTHOR]

Many macrophyte species exhibit a high degree of plasticity, enabling them to thrive in various aquatic ecosystems. Identifying the growth conditions of individual aquatic plant species during research or specimen collection is not always possible. In many cases, the nature of the planned research does not necessitate recognizing environmental conditions. However, the scope of identifying the habitat parameters of the collections of submerged aquatic plant herbariums provides an opportunity for further research. This paper explores the possibilities of using isotopic signals of plants, supported by spectral analyses of powdered plant materials, to ascertain the environmental conditions from which the samples were collected. The results obtained from the stable carbon and nitrogen isotope compositions (δ13CORG and δ15NORG) and the analysis of spectral spectra via FTIR-ART (Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance) of plant material (Elodea canadensis Michx. species) collected from various habitat ecosystems, including rivers and both hard- and softwater lakes, exhibited significant distinctions between these habitats. Particularly high values of δ15NORG were recorded in the material from rivers. The stable carbon and nitrogen isotope compositions did not differentiate between the material collected from softwater and hardwater lakes. Nevertheless, when comparing the isotopic findings with the FTIR-ATR spectral analysis focused on identifying characteristic peaks associated with the presence of calcium carbonate, noticeable differences were observed in the presence and intensity of calcium carbonate peaks in the material. These differences were only evident when nondecarbonated plant material from hardwater lakes was used for the FTIR-ATR analysis. To the best of the author's knowledge, the combination of methods applied in this study to identify the origin of E. canadensis from various freshwater environments is the first application of its kind that could enable the rapid identification of plant material origin. Such identification could prove useful in environmental, ecological, and paleoenvironmental research. The increased knowledge of macrophytes' δ13CORG and δ15NORG values might also be essential in further tracking accelerated eutrophication based on aquatic vegetation's isotopic signals. This might be important due to the assumption that the increased rate of eutrophication influences organic matter sedimentation in aquatic ecosystems, especially lakes. [ABSTRACT FROM AUTHOR]

For casework applications, understanding the source processes used to create a material and the effects of those sources on the results obtained by Isotope Ratio Mass Spectrometry (IRMS) of a bulk material is important. Likewise, understanding the effect of environment, home/office printing processes and some forensic testing in at least a basic context, ensures that in casework, enough information on the effects of these variables is available during comparison and interpretation. In this study, which focuses on oxygen isotopic abundance measurements, both fractionation and mixing effects were observed within the pulping and production process. Also observed in the carbon isotopic experiments, sampling that included toner changed the measured isotopic abundance values of the paper and should be avoided in casework. Inkjet printing processes were not shown to have an effect on the paper oxygen abundance values. Samples that were treated for fingerprints using 1,2-Indandione-Zn prior to sampling showed the greatest risk for misinterpretation of whether two samples had originated from the same source. While this study provides a good basis and understanding of the effects of a range of factors on document paper oxygen isotope values, further testing for a range of specific casework scenarios is required and should be undertaken on a case by case basis as the need arises. [ABSTRACT FROM AUTHOR]

Mid-infrared laser absorption spectroscopy utilizing a high-finesse optical cavity enables high precision trace analysis of gas molecules. In particular, optical detection of radiocarbon (14C) based on cavity ringdown spectroscopy using a quantum cascade laser (QCL) is gaining attention as an alternative to accelerator mass spectrometry. This paper reports a compact-packaged narrow-linewidth QCL system utilizing resonant optical feedback from an external V-shaped cavity. Based on frequency noise analysis, the derived laser linewidth is 44 kHz for 100 μs integration time with the capability to perform seamless frequency scanning around 10 GHz. We installed this laser system within a table-top cavity ringdown spectrometer for 14CO2. A single-shot detection limit of 1.2 × 10−9 cm−1 Hz−1/2 leading to a detectable abundance evaluated from a noise analysis of 0.2 in fraction modern 14C for a 10-s averaging time was achieved. This capability of rapid analysis for 14CO2 is suitable for various applications requiring trace 14C analysis. [ABSTRACT FROM AUTHOR]

In this paper we describe the implementation of the carbon isotopes 13 C and 14 C (radiocarbon) into the marine biogeochemistry model REcoM3. The implementation is tested in long-term equilibrium simulations where REcoM3 is coupled with the ocean general circulation model FESOM2.1, applying a low-resolution configuration and idealized climate forcing. Focusing on the carbon-isotopic composition of dissolved inorganic carbon (δ13 C DIC and Δ14 C DIC), our model results are largely consistent with reconstructions for the pre-anthropogenic period. Our simulations also exhibit discrepancies, e.g. in upwelling regions and the interior of the North Pacific. Some of these differences are due to the limitations of our ocean circulation model setup, which results in a rather shallow meridional overturning circulation. We additionally study the accuracy of two simplified modelling approaches for dissolved inorganic 14 C, which are faster (15 % and about a factor of five, respectively) than the complete consideration of the marine radiocarbon cycle. The accuracy of both simplified approaches is better than 5 %, which should be sufficient for most studies of Δ14 C DIC. [ABSTRACT FROM AUTHOR]

Cave carbonate minerals are an important terrestrial paleoclimate archive. A few studies have explored the potential for applying carbonate clumped isotope thermometry to speleothems as a tool for constraining past temperatures. To date, most papers utilizing this method have focused on mass-47 clumped isotope values (Δ 47) at a single location and reported that cave carbonate minerals rarely achieve isotopic equilibrium, with kinetic isotope effects (KIEs) attributed to CO 2 degassing. More recently, studies have shown that mass-47 and mass-48 CO 2 from acid digested carbonate minerals (Δ 47 and Δ 48) can be used together to assess equilibrium and probe KIEs. Here, we examined 44 natural and synthetic modern cave carbonate mineral samples from 13 localities with varying environmental conditions (ventilation, water level, pCO 2 , temperature) for (dis)equilibrium using Δ 47 -Δ 48 values, in concert with traditional stable carbon (δ13C) and oxygen (δ18O) isotope ratios. Data showed that 19 of 44 samples exhibited Δ 47 -Δ 48 values indistinguishable from isotopic equilibrium, and 18 (95 %) of these samples yield Δ 47 -predicted temperatures within error of measured modern temperatures. Conversely, 25 samples exhibited isotopic disequilibria, 13 of which yield erroneous temperature estimates. Within some speleothem samples, we find Δ 47 -Δ 48 values consistent with CO 2 degassing effects, however, the majority of samples with KIEs are consistent with other processes being dominant. We hypothesize that these values reflect isotopic buffering effects on clumped isotopes that can be considerable and cannot be overlooked. Using a Raleigh Distillation Model, we examined carbon and oxygen isotope exchange trajectories and their relationships with dual clumped isotope disequilibria. Carbon isotope exchange is associated with depletion of both Δ 47 and Δ 48 relative to equilibrium, while oxygen isotope exchange is associated with enrichment of both Δ 47 and Δ 48 relative to equilibrium. Cave rafts collected from proximate locations in Mexico exhibit the largest average departures from equilibrium ( Δ Δ 47 ¯ = −0.032 ± 0.007, Δ Δ 48 ¯ = −0.104 ± 0.035, where ΔΔ i is the measured value – the equilibrium value). This study shows how the Δ 47 -Δ 48 dual carbonate clumped isotope framework can be applied to a variety of tcave carbonate mineral samples, enabling identification of isotopic equilibria and therefore quantitative application of clumped isotope thermometry for paleoclimate reconstruction, or alternatively, constraining the mechanisms of kinetic effects. [ABSTRACT FROM AUTHOR]

From the Pueblo I to the Late Pueblo III periods (725–1280 CE), in the Mesa Verde and McElmo Dome regions of the American Southwest, turkey use continuously increased, then declined during the final period of widespread residential occupation in the region. Increasing aridity in the Late PIII period may have limited agricultural productivity, and consequently, the ability to provision turkeys. In this paper, we use C, Sr, and O isotope analyses of turkey bone (n = 95) from archaeological contexts to investigate whether the turkey diets and the locations where they were raised changed over time as a consequence of demographic and social changes in the region. Our results show that almost all turkeys were raised by Puebloan maize farmers in or in the vicinity of the McElmo Dome region and fed a C4-based diet, presumably dominated by maize, during the whole period under study. However, it seems that they were fed less maize during the late thirteenth century. Perhaps facing lower yield harvests, maize was prioritized for human consumption, which resulted in less intensified turkey production efforts and reduced investment in maize-provisioned flocks. Our results also attest to the occasional use of local (likely wild) turkeys not provisioned with maize, and one wild turkey brought in from a more distant area. [ABSTRACT FROM AUTHOR]

The EU Carbon Border Adjustment Mechanism (CBAM), which is regarded as the EU's key policy tool to address carbon leakage, might have a non-negligible impact on China's exports, as China is an important trading partner for the EU's carbon-intensive products. This paper uses the GTAP-E model to simulate the impact of the EU CBAM on China's exports to the EU from four aspects, export price, trade structure, trade value and terms of trade, by setting up multiple scenarios. The results show that the EU CBAM reduces the export prices of China's taxed sectors to the EU, and that the export prices of other sectors show the same change characteristics. The export volume of China's taxed sectors decreases differently with the export transfer effect and export inhibition effect. In terms of trade value, the EU carbon tariffs not only reduce China's export value but also lead to a reduction in EU exports. The implementation of the EU CBAM improves the terms of trade of the EU and worsens the terms of trade of China. An expansion of the scope of taxation and a change in the calculation method of carbon emissions would aggravate the change in the terms of trade. The results suggest that feasible measures should be taken to strengthen international cooperation, promote the construction of a unified national carbon market and export diversification, and establish a firm carbon emission accounting system in order to mitigate the negative impact of the EU CBAM. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the issues of handling reactor graphite. The content of 14C in RBMK graphite is compared with the natural content and emissions from other technogenic impacts. The scale of natural fluctuations in the natural content of 14C and their relationship with technogenic impacts are discussed. Possible doses due to the release of 14C from a hypothetical near-surface storage of reactor graphite during normal operation and accidents are estimated. [ABSTRACT FROM AUTHOR]

Interspecific C transfer was studied in laboratory microcosms containing pairs of 6-month-old Betula papyrifera Marsh. and Pseudotsuga menziesii (Mirb.) Franco seedlings growing in individual, root-restrictive (28 μm pore size) pouches filled with field soil. Interspecific transfer was examined by reciprocal labelling of seedlings with 13CO2(gas) and 14CO2(gas). At the time of labelling, the root zones of ectomycorrhizal (EM) B. papyrifera and P. menziesii were interconnected by an extensive network of EM mycelium. Carbon transferred through EM connections was distinguished from that through soil pathways by comparing microcosms where interconnecting hyphae were left intact vs. those where they were severed immediately before labelling. Transfer was bidirectional, and represented 5% of total isotope uptake by both B. papyrifera and P. menziesii together. P. menziesii received on average 50% more 14C and 66% more 13C from paper birch than vice versa, however, differences between species were not statistically significant. Neither net nor bidirectional transfer differed between severing treatments, leaving in question the relative importance of EM hyphae versus soil transfer pathways. The tendency for P. menziesii to receive more isotope than B. papyrifera corresponded with a 10-fold greater net photosynthetic rate per seedling and two-fold greater foliar N concentration of B. papyrifera than P. menziesii. [ABSTRACT FROM AUTHOR]

Isotopic analysis has become one of the most popular arenas of archaeological science, in part due to its versatility to uncover intriguing insights from a range of organic and inorganic archaeological materials. However, alongside an increase in popularity, the field has seen the rise of dissemination of publications that do not pass quality control, do not apply robust interpretative frameworks, or do not report data in ways that would make them amenable to critical evaluation or inclusion in large meta-analyses. This paper represents an effort to clarify some of the most pressing weaknesses and misconceptions in 'traditional' applications of isotopic techniques in archaeology: measurement of stable carbon, nitrogen, and oxygen isotope values of organic and inorganic materials (bulk bone collagen, bulk tooth dentine, seeds; bulk and incremental tooth enamel, molluscan shells), and strontium isotope ratio analysis of tooth enamel and cremated bone. The discussion centers on three key aspects of research: (1) Selecting samples, with advice on building comparative baselines (or more appropriately 'base intervals ') and words of caution on interpreting stable carbon isotope values measured during AMS radiocarbon dating. (2) Handling data, including tips on exploratory data analysis, graphical visualization, and statistical assessment of differences between groups; with particular reference to the Statement on p -values published by the American Statistical Association. (3) Reporting results, with advice on using correct terminology and decimal points, calculating measurement precision and accuracy, and communicating results using effective scientific language. The advice provided in this paper does not cover all aspects of project design and dissemination but will hopefully provide clarification within the above key areas and inspire further discussion of effective and impactful applications of isotopic techniques in archaeology. [ABSTRACT FROM AUTHOR]

The investigation of the impact of the Fukushima accident is still going on although more than ten years have passed since the disaster. The main goal of this paper was to summarize the results of tritium and radiocarbon determinations in different environmental samples, possibly connected with the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. A document containing compiled data may serve as a solid basis for further research in the selected fields. To accomplish such effort, we went through dozens of relevant published papers, reporting 3H and 14C activity concentrations in precipitations, groundwater, seawater, river systems, tree rings, and, in some more extraordinary samples, such as herbaceous plants or debris from the damaged reactor buildings. As the referenced results would not be obtainable without adequate analytical techniques, the most common methods for routine measurement of tritium and radiocarbon concentrations are discussed as well. We believe that the correct identification of the affected environmental compartments could help quantify the released 3H and 14C activities and track their following fate, which could be especially important for plans to discharge contaminated water from the FDNPP in the upcoming years. [ABSTRACT FROM AUTHOR]

The ancient southern Levantine city of Gezer is well-known from Egyptian, Biblical and Assyrian sources, associated with power struggles, conquests, and intriguing tales involving figures such as Milkilu and Amenhotep III, Merneptah, the Philistines, Solomon and his unidentified pharaonic father-in-law, and Shishak / Sheshonq I. Since the identity of Gezer with "Tell Jezer" is quite literally 'set in stone' by some dozen boundary inscriptions, along with impressive Bronze and Iron Age remains, research at this site provides a unique opportunity to compare text and archaeology, as well as bring to light the undocumented everyday lives of the city's inhabitants. In this endeavour, independent scientific dating is crucial for anchoring the remains chronologically. This paper presents the first substantial radiocarbon dataset and Bayesian chronological analysis for Gezer spanning the last part of the Late Bronze Age (LBA; LB IIB) through Iron Age II. The dataset derives from an essentially continuous stratigraphic sequence exposed in recent years by the Tandy expedition along the central-southern edge of the site. The results allow us for the first time to independently determine the site chronology, test the viability (from a chronological perspective) of proposed historical correlations, and contribute to debates on Philistine and Iron Age chronology. [ABSTRACT FROM AUTHOR]

Stable carbon isotopes of long-chain n-alkanes in lake sediments have been used for reconstructing past environmental changes. Gas chromatography isotope ratio mass spectrometry coupled to a combustion unit is the commonly applied technique for compound-specific carbon isotope analysis. This paper shows that sulfur in the lacustrine sediment can cause severe interference during the mass spectrometric measurement, leading to significant biases in δ13C of n-alkane. The δ13C deviation could be resulted from additional 12C33S+, 13C32S+ at mass-to-charge ratio (m/z) 45, and 12C34S+, H2C32S+at m/z 46, respectively. Such elemental sulphur interference can be eliminated by the activated copper in the pretreatment procedure. [ABSTRACT FROM AUTHOR]

This paper presents the first continuous multi-proxy record of climate and vegetation change from the central Namib Desert extending over much of the last ca. 39,000 years. Derived from rock hyrax middens, evidence from stable carbon and nitrogen isotopes, pollen, and microcharcoal reveals significant differences between glacial-age and Holocene climates and vegetation types. Although still arid to semi-arid, conditions during Marine Oxygen Isotope Stages (MIS) 2–3 were significantly more humid than in the Late Holocene. Considerable associated vegetation change is apparent, with cooler temperatures and higher/more-regular rainfall promoting the westward expansion of relatively mesic shrubby karroid vegetation during MIS 2–3. With the last glacial–interglacial transition, increasing temperatures and less/less-regular rainfall resulted in marked vegetation changes and the establishment of current xeric grasslands. The inter-plant spacing of the karroid vegetation promoted by wetter conditions does not carry fire effectively, and the microcharcoal record indicates that more extensive fires may develop only with the development of grassier vegetation under drier conditions. As with other terrestrial records from the Namib Desert and environs, no Cape flora elements were found to support previously hypothesised expansion of the Fynbos Biome during the last glacial period. [ABSTRACT FROM AUTHOR]

Abstract: Groundwater recharge and evolution in the Quaternary aquifer beneath the Dunhuang Basin was investigated using chemical indicators, stable isotopes, and radiocarbon data to provide guidance for regional water management. The quality of groundwater and surface water is generally good with low salinity and it is unpolluted. The dissolution of halite and sylvite from fine-grained sediments controls concentrations of Na+ and K+ in the groundwater, but Na+/Cl− molar ratios >1 in all samples are also indicative of weathering of feldspar contributing to excess Na+. The dissolution of carbonate minerals yields Ca2+ to the groundwater, thereby exerting a strong influence on groundwater salinity. The δ18O and δ2H values in unconfined groundwater are enriched along the groundwater flow path from SW to NE. In contrast, confined groundwater was depleted in heavy isotopes, with mean values of −10.4‰ δ18O and −74.4‰ δ2H. Compared with the precipitation values, all of the groundwater samples were strongly depleted in heavy isotopes, indicating that modern direct recharge to the groundwater aquifers in the plains area is quite limited. The unconfined water is generally young with radiocarbon values of 64.9–79.6 pmc. In the northern basin, radiocarbon content in the confined groundwater is less than 15 pmc and an uncorrected age of ∼15ka, indicates that this groundwater was recharged during a humid climatic phases of the late Pleistocence or early Holocene. The results have important implications for inter-basin water allocation programmes and groundwater management in the Dunhuang Basin. [Copyright &y& Elsevier]

Before amalgamating published isotope data, comparability should be demonstrated. This paper compares carbon and oxygen isotopic compositions of 30 enamel samples measured by two laboratories. The aims were to see what, if any, isotopic variation was observed, to determine the causes as needed and to correct if possible. Bioapatite was acidified at 90°C in 2006 and at 26°C in 2017, while δ values were corrected via one‐point normalization in 2006 and by two‐point normalization in 2017. One case (of the 30) produced different δ values between the analysis dates, suggesting contamination. Repeated carbon isotope ratio measurements were not meaningfully different. Repeated oxygen isotope ratio measurements were significantly different, even following correction for acid‐carbonate fractionation at different temperatures and the renormalization of 2017 δ values using one point; however, differences were not meaningful for interpretations. Results were used to calculate real interpretative differences (RIDs) for comparing enamel bioapatite as 0.6‰ for δ13C values and as 1.6‰ for δ18O values. [ABSTRACT FROM AUTHOR]

Recent radiocarbon redating of key sites and events in Huron-Wendat archaeology has shaken dominant accounts of early colonial history. This paper emphasizes the importance of storytelling in archaeology. I consider how refined date estimates for key Huron-Wendat archaeological sites have impacted understandings of conflict, confederacy-formation, and the reception (or not) of early European materials and persons. The paper highlights how this work affects processes of commemoration and collaboration, as well as the importance of shared authority and Huron-Wendat leadership in rewriting contact-era archaeological histories. This project has generated productive new directions for meaningful collaboration between archaeologists and Indigenous researchers and heritage managers. [ABSTRACT FROM AUTHOR]

Cleaning Validation is a crucial process in pharmaceutical manufacturing, as it verifies that cross-contamination levels are below acceptable limits. The use of Mid-Infrared (IR) spectroscopy has long been proposed as a rapid method enabling real-time release, but only with the recent emergence of a handheld Fourier-Transform IR (FTIR) does a feasible solution exist for practical implementation in pharmaceutical manufacturing plants. This paper address the model development challenges for multi-product plants without complete traceability of production equipment and produced product. This is done by developing a partial least squares discriminant analysis model determining if the sample is clean or not clean compared to a residual acceptance limit, based on total organic carbon (TOC) measurements. The model is built and tested on artificial samples printed with a chemical printer for multiple products with different spectral peaks based on 91 samples in the calibration set and tested on 30 samples in the validation set. Furthermore, the model also incorporates spectra from surfaces with different surface roughness. The evaluation of the model is based on sensitivity, specificity and class error. The model outperforms or performs equally well as TOC swab with sampling error, dependent on the sampling error distribution for the TOC swab. [ABSTRACT FROM AUTHOR]

The Doppler coefficient represents the primary source of passive and instantaneous negative reactivity feedback to limit peak power excursion during reactivity-initiated accidents as well as a nonnegligible negative reactivity source that changes between cold zero-power and hot zero-power conditions. Furthermore, the mechanism behind the Doppler coefficient may also contribute to an increase in the buildup of Pu under normal operating conditions. As such, its treatment is critical in the design and evaluation of the safety and control of nuclear systems. This paper provides a brief overview of the physical source of the Doppler effect through resonance broadening from first principles as well as an exploration of some recent developments in the treatment of elastic scattering in the Monte Carlo codes Tripoli4® and MCNP. This exploration results in a detailed look at the effect different elastic scattering kernels have on the radiative capture, fission, and elastic scattering rates as they directly tie into the calculation of the Doppler coefficient via the six-factor formula. Also provided is some insight into the propagation of the a priori uncertainty of 238U resonance parameters. This work is performed pursuant to the development of a new experimental program to measure the Doppler coefficient in a zero-power reactor both more accurately and to higher temperatures (1500°C to 2000°C) than has been done in the past at the MINERVE facility at Cadarache. [ABSTRACT FROM AUTHOR]

Employment is the foundation of people ’s livelihoods, and a low-carbon transition is a key development theme for China in the future. The impact of reducing CO2 emissions as a hard macroeconomic constraint on the labor market is an important economic issue. This paper used China’s low-carbon city pilot policy as a representative policy to study the low-carbon transition. Firstly, based on the analysis of typical economic facts and policy texts, it was found that there might exist two distinct low-carbon transition approaches in China. The study then examined the differences in the policy impact on labor employment in the first and second batches of pilot cities, analyzed the underlying mechanisms, and finally constructed a general equilibrium model based on the empirical findings to further elaborate the heterogeneous impact pathways from a theoretical perspective. The study showed that: ① There was a difference in the policy impact on employment in the first and second batches of pilot cities. The policy increased employment in secondary and tertiary industries and total employment in the first batch of pilot cities, but it increased employment in tertiary industries and decreased employment in secondary industries in the second batch of pilot cities. ② There was a difference in the mechanisms of policy impact on employment in the first and second batches of pilot cities. Under the influence of the policy, the first batch of pilot cities adopted the low-carbon transition approach of focusing resources on the secondary industry, while the second batch of pilot cities adopted the lowcarbon transition approach of focusing resources on the tertiary industry. ③ The low-carbon transition approaches of the two batches of pilot cities had their own advantages and disadvantages. The approach of the first batch of pilot cities achieved a reduction in total CO2 emissions and an increase in the number of jobs, with the disadvantage of increasing the intensity of CO2 emissions and reducing the disposable income of workers, failing to improve the quality of employment. However, the approach of the second batch of pilot cities reduced the intensity of CO2 emissions, increased employment in the tertiary industry, and increased the disposable income of workers, effectively improving the quality of employment but failing to achieve a reduction in total CO2 emissions and an increase in total employment. Accordingly, China’s goals of reaching peak carbon emissions and achieving carbon neutrality can be achieved either by industrial transformation and upgrading or by enhancing the development of the tertiary industry, but the best way is to develop the tertiary industry on the basis of industrial transformation and upgrading without blindly adopting the de-industrialization approach to achieve the peak carbon emission goal. [ABSTRACT FROM AUTHOR]

Xinjiang, in Northwestern China, was a key point in the prehistoric trans-Eurasian network of exchange and played an important role in facilitating the dispersal of crops across Eurasia. Millet crops were first cultivated and used ca. 10,000 years ago in Northern China, from where they spread via different routes, leaving intriguing traces in various sites across Xinjiang. This paper presents the latest data on millet in Xinjiang. By employing a multidisciplinary approach, including radiocarbon dating, archaeobotanical evidence, and carbon isotope datasets, this study explores potential routes by which millet entered Xinjiang and traces its expansion from the third millennium BC to the 10th century AD. The research highlights the significant role of millet in shaping the ancient economies and cultures of Xinjiang and Central Asia, while also underscoring the importance of further investigation to uncover the complex pathways of its dispersal across Eurasia. [ABSTRACT FROM AUTHOR]

Cultural interaction and exchange across the Bering Strait of northern Alaska played a central role in the emergence of Arctic maritime adaptations. Yet poor chronological control limits our ability to explore processes of cultural change over the last 5000 years. We address this problem by synthesizing the available radiocarbon record for the region, carrying out Bayesian analysis of a regional radiocarbon database, and analyzing the BAR-1 (Birnirk) site using new dates published in this paper. Our synthesis and our illustrative analysis of the BAR-1 site highlights several intriguing temporal and spatial trends with implications for interaction between cultural groups. Our analysis also underscores the uncertainty associated with dating cultural phases and identifies specific areas where additional research is needed to further our understanding of cultural interaction in this complex region. [ABSTRACT FROM AUTHOR]

This paper examines eight marble samples from the architectural elements and liturgical furniture of the ecclesiastical complex of Santa Giustina in Padova (Italy), founded by the Rufus Venantius Opilio before AD 524. The provenance determination of the marbles was carried out by means of a multi-analytical approach combining mineralogical–petrographic investigations, performed by microscopic observations of thin sections, and the measurement of the ratios of stable carbon and oxygen isotopes. The results obtained were compared with up-to-date petrographic and isotopic databases (Antonelli and Lazzarini 2015), and they showed that the analyzed marbles come from the quarries of the island of Proconnesus in Asia Minor, modern Marmara Adası (Turkey). Archaeometric evidence, together with the stylistic and functional analysis of the pieces, suggests the direct importation of a complete set of sculptures, shipped at different stages of workmanship from the workshops of Constantinople and expressly ordered by a single patron, who can be identified as Opilio, founder of the basilica of Santa Giustina and praetorian prefect at the court of King Theodoric. [ABSTRACT FROM AUTHOR]

A recent archaeological survey disclosed a whole, S-shaped "grooved club" similar to examples from Basketmaker II contexts of the Four-Corners. It represents the farthest north example of this artifact type in the Southwest, occurring outside the traditional area of western Basketmaker II occupation. Artifacts like this were once thought to be a characteristic Basketmaker II trait of the Four Corners, but examples come from sites distributed throughout the Southwest and beyond and from temporal intervals well before and after Basketmaker II. A study of the new find promised to shed some additional light on this enigmatic artifact class by expanding the geographic range of known occurrences, providing an additional radiocarbon age estimate, and perhaps revealing new or corroborative information about use. This paper covers these aspects and more. Un estudio arqueológico reciente reveló un "mazo ranurado" completo en forma de S similar a los ejemplos de los contextos de Basketmaker II de las Cuatro Esquinas. Representa el ejemplo más al norte de este tipo de artefacto en el suroeste, que se encuentra fuera del área tradicional de ocupación occidental de Basketmaker II. Alguna vez se pensó que artefactos como este eran un rasgo característico de Basketmaker II de Four Corners, pero los ejemplos provienen de sitios distribuidos por todo el suroeste y más allá y de intervalos temporales mucho antes y después de Basketmaker II. El estudio del nuevo hallazgo prometió arrojar algo de luz adicional sobre esta enigmática clase de artefactos al expandir el rango geográfico de ocurrencias conocidas, proporcionar una estimación adicional de la edad del radiocarbono y quizás revelar información nueva o corroborativa sobre el uso. Este documento cubre estos aspectos y más. [ABSTRACT FROM AUTHOR]

This exploratory study proposes an original intra‐life history investigation through sequential analysis of the isotopic composition of carbon, nitrogen, and sulfur (CNS) on both primary and secondary dentin of a tooth (M1). We focus on an elderly woman from Longobard Italy (6th to 8th c. CE), who showed an unprecedented case of cranial surgery, presented in a companion paper by Micarelli and colleagues. Sequential stable CNS isotope composition of first molar dentin collagen allows us to infer diet, mobility, health, and physiological stress between approximately 3 months after birth to 9.5 years old (primary dentin) and between early adulthood until death (secondary dentin). Isotopic results on primary dentin highlight the following: (i) a long weaning period (ending at approximately 4 years), followed by (ii) a specific diet, including the contribution of C4 crops in early childhood (approximately 5.5 years), possibly concomitant with mobility. While secondary dentin shows a generally homogeneous diet during adulthood, the longitudinal analysis provided information on specific stresses that likely occurred in periods of difficult health conditions. This work emphasizes the importance of measuring complete dentin sequences (including secondary when present) for isotopic analysis to broaden intra‐life histories in ancient populations. [ABSTRACT FROM AUTHOR]

Owing to a rapid rate of depletion of conventional energy resources and to keep pace with the ever increasing energy demand, scientists all over the world are looking for some alternate source. Coal bed methane (CBM) is one of them. With the discovery of coalbed gas from an oil and gas producing basin- the San Juan basin in Colorado and New Mexico by AMOCO in early 1980's, the attention of world-wide hydrocarbon industry shifted to evaluation of CBM potential of Tertiary basins. The Tertiary Cambay basin in Gujarat is a known onland hydrocarbon province of India and has been producing oil since 1958. During drilling for petroleum, thick Eocene coal seams are encountered at varied depths in Mehsana area and further north. In 2004, few coalbed methane (CBM) blocks were awarded in northern Cambay basin and contagious Barmer Basin. The present paper entails the results of investigation carried out for CBM in the deep-seated coals of Sanchore and Tharad area in north Cambay basin. The methane content of the desorbed gases varies from 20–68%. The stable carbon isotope study (δ13C) shows that the desorbed gas is dominantly biogenic but the compositional analysis of desorbed gas reveals significant fractions of ethane (C2) and butane (C3) indicating the gases to be of mixed origin. Further, presence of high CO2 content is observed which varies from 20–45% of the total volume of desorbed gas. The estimated mean CBM resource of the study area is ∼ 46 billion cubic meters. [ABSTRACT FROM AUTHOR]

The paper presents original results of comprehensive geochemical studies of samples of oils, condensates, gases, core, and cuttings from wells drilled in the north of Western Siberia. The studies involved chromatographic and mass spectrometric determinations of the molecular and isotopic composition of the oils, gases, condensates, and rock extracts. Analysis of the results, considered together with literature data, made it possible to draw conclusions regarding the source of the hydrocarbons and the mechanism of formation of their accumulations. Information on the molecular and isotopic composition of the fluids and the distribution of their accumulations and fields in the sedimentary cover shows that most of them are of polychronic and polygenic origin. Features of the molecular and isotopic composition of the fluids make it possible to evaluate the contribution of various sources to the formation of hydrocarbon accumulations. The composition of their liquid component was formed as a result of the generation of hydrocarbons by the organic matter of Jurassic source rocks. The Lower and Middle Jurassic rocks with non-marine organic matter also made a significant contribution to the formation of the gas component of deposits in the north of Western Siberia, whereas the Cretaceous rocks generated only dry gas and were likely the main source of gas for the giant fields, whose methane has a light carbon isotope composition. The use of the isotopic composition of carbon in combination with molecular parameters makes it possible to clarify the conditions under which a particular field was formed and to elucidate the migration pathways and distances of hydrocarbon fluids to their accumulation sites. [ABSTRACT FROM AUTHOR]

China's rapid economic growth is accompanied by industrial agglomeration (IA) and environmental pollution. Although IA has played an important role in reducing environmental pollution, its effect on carbon emissions is still debatable and deserves further study. In this context, this paper constructs a two-sector general equilibrium model including households and firms to explore the mechanisms of IA on carbon emissions and finds that IA mainly affects carbon emissions through the agglomeration effect and congestion effect. Then, based on the balanced panel data for 30 Chinese provinces from 2003 to 2019, this study employs the dynamic spatial panel model to investigate the nexus between different types of IA and carbon emissions. The empirical results reveal that a significant positive spatial dependence is verified in the regional carbon emissions of China, indicating that carbon emissions exhibit a remarkably spatial spillover effect. Meanwhile, there are significant variations in the influence of different types of IA on carbon emissions. Specifically, specialized agglomeration (SA) positively affects carbon emissions, while the impact of diversified agglomeration (DA) on carbon emissions is negative, implying that China's DA may contribute to carbon emission control. In addition, there is regional heterogeneity in the effect of IA on carbon emissions, with the western region having a significantly greater effect than the eastern and central regions. Therefore, the Chinese government should follow the notion of integrating territory administration and interregional communication and formulate regionally differentiated environmental governance policies to promote carbon emission reduction in the future. [ABSTRACT FROM AUTHOR]

Faid was a major pilgrim Islamic oasis located 120 km southeast of the Ha'il Province, northwest of Saudi Arabia. It was founded on the major Hajj Road between Baghdad/Kufa and Medina and was developed by Zubaydah bint Ja'far, granddaughter to the Caliph Abu Ja'far al-Mansur (the founder of Baghdad) and wife to the fifth Abbasid Caliph, Harun Ar-Rasid 775-785 CE. Therefore, during the reign of Harun Ar-Rasid Caliph, the major pilgrim road was renamed from Darb Heerah to Darb Zubaydah. The archaeological site in Faid was referenced and described by several travellers and scholars and excavated by the Heritage Commission, Ministry of Culture, Saudi Arabia 1998-2012. From 2014-2022, the University of Ha'il conducted nine fieldwork seasons at the site. The authors directed the last four seasons, which revealed numerous new discoveries from stratified excavations. This study aims to reconstruct the occupation chronology at the site based on stratigraphic contexts and supported by radiocarbon dating, artefact studies, and written resources. Three occupation horizons were identified at the site; the early Abbasid period was the dominant occupation. The resulting radiocarbon calibrated ages were consistent with the preliminary archaeological studies carried out by the authors. The results presented in this paper represent an attempt to reconstruct the chronology of the study site. [ABSTRACT FROM AUTHOR]

The scientific study of Neolithic monuments holds fundamental keys to the analysis of early social complexity. This is often impeded by the challenges involved in understanding their temporality and, particularly, their initial construction dates. This problem is most severe in monuments that were not predominantly used for burial and went on to have long biographies in which activity in later periods obliterated the material record of the earliest phases. That was certainly the case of the Menga dolmen, part of the Antequera World Heritage site (Málaga, Spain), and one of the most remarkable megaliths in Europe, for which, after nearly 200 years of explorations and research, no firm chronology existed. The research presented in this paper shows how this problem was tackled through a multimethod, scientific, and geoarchaeological approach. The analysis of 29 fresh numerical ages, including radiocarbon determinations as well as optically stimulated luminescence, thermoluminescence, and uranium-thorium dates, led to the successful establishment of Menga's construction date and the subsequent contextualization of the monument within the social and cultural background it arose in. Placing the dolmen in the context of its time of "birth" introduces entirely new possibilities for its interpretation, both in terms of local and supralocal social and cultural processes. [ABSTRACT FROM AUTHOR]

The paper presents six samples originating from archaeologically investigated contexts in the Early Iron Age site of Saharna–Țiglău. Three samples were collected, after anthropological analysis, from funerary features excavated in 2022, and the remaining samples were taken from pits within the settlement. Calibration of the six AMS radiocarbon data places the chronological sequence with a 95.4% probability in the range calBC 1284-797. From the association of the data, it is almost obvious to conclude that one of the earliest known dates for an Early Iron Age context with stamped pottery in the Carpathian-Balkan area has been recorded at Saharna–Țiglău. [ABSTRACT FROM AUTHOR]

A multi-technique approach combining petrographic, cathodoluminescence, and stable isotope analyses is commonly used in provenance studies of archaeological marbles. In the present paper, this characterization approach transcends provenance, and it is applied to the reconstruction of fragmented sculptures. The potential of this novel application of archaeometric measurements is illustrated with a case study consisting in 16 scattered marble fragments retrieved from a Roman villa (Els Munts) near Tarraco (presently Northeastern Spain). The samples were grouped taking into account their similarity in quantified parameters such as the cathodoluminescence color clusters and the stable carbon and oxygen isotopic ratios. The results permitted classification of the fragments into three groups corresponding to three different statues depicting Antinous (7 fragments), Minerva goddess (4 fragments), and an undetermined character (3 fragments). Two other fragments could not be ascribed to any particular statue. The archaeometric grouping provides arguments that can be used to confirm or refute archaeological hypotheses of statue reconstructions. [ABSTRACT FROM AUTHOR]

There is a great demand for online high-precision monitoring of carbon isotope methane in the fields of atmospheric monitoring, geological exploration, oil and natural gas extraction, etc. However, the current detection method has some problems, such as the difficulty to ensure a wide concentration detection range while detecting an ultra-low concentration of carbon isotope methane with high accuracy, and a long detection period. To address these issues, in this paper, we propose TC/WMS-TDLAS, temperature-controlled/wavelength-modulated spectroscopy of tunable diode laser absorption spectrometry for the detection of ultra-low concentration carbon isotope methane. Also, we analyze the effect of temperature variation on the absorption signal of the infrared spectrum of carbon isotope methane and further investigate the interaction effect of the two isotope detection when the concentrations of 12CH4 and 13CH4 differed greatly. In addition, we develop a calibration model for detection when the difference between 12CH4 and 13CH4 concentrations is large. The experimental results show that TC/WMS-TDLAS can achieve an efficient analysis of 12CH4 and 13CH4 concentrations when the gas volume is less than 200 mL with a detection period less than 2 s. The detection error for ultra-low concentration carbon isotope methane is less than 1%, and the lower limit of detection for the concentration of 12CH4 and 13CH4 is 0.5 × 10−6 (0.5 ppmv) and 0.1 × 10−6 (0.1 ppmv), respectively. It also demonstrates that TC/WMS-TDLAS has significantly improved the detection performance of TDLAS for ultra-low concentration carbon isotope methane and it is promising for future application. [ABSTRACT FROM AUTHOR]

This paper reviews the evidence for long term trends in anthropogenic activity and population dynamics across the Holocene in the central Mediterranean and the chronology of cultural events. The evidence for this has been constituted in a database of 4608 radiocarbon dates (of which 4515 were retained for analysis following initial screening) from 1195 archaeological sites in southern France, Italy and Malta, spanning the Mesolithic to Early Iron Age periods, c. 8000 to 500 BC. We provide an overview of the settlement record for central Mediterranean prehistory and add to this an assessment of the available archaeological radiocarbon evidence in order to review the traditional narratives on the prehistory of the region. This new chronology has enabled us to identify the most significant points in time where activity levels, population dynamics and cultural change have together caused strong temporal patterning in the archaeological record. Some of these episodes were localized to one region, whereas others were part of pan-regional trends and cultural trajectories that took many centuries to play out fully, revealing prehistoric societies subject to collapse, recovery, and continuing instability over the long-term. Using the radiocarbon evidence, we model growth rates in the various regions so that the tempo of change at certain points in space and time can be identified, compared, and discussed in the context of demographic change. Using other published databases of radiocarbon data, we have drawn comparisons across the central Mediterranean to wider prehistoric Europe, and northern Africa. Finally, we include a brief response to the synchronously published but independently developed paper (Palmisano et al. in J World Prehist 34(3), 2021). While there are differences in our respective approaches, we share the general conclusions that large-scale trends can been identified through meta-analyses of the archaeological record, and these offer new perspectives on how society functioned. [ABSTRACT FROM AUTHOR]

The paper continues a complex study of the Santonian–Campanian boundary of the Aksu-Dere and Kudrino-2 sections (Bakhchisarai region, Southwestern Crimea), the sedimentological and biostratigraphic data on which are provided in paper 1. This work presents the paleomagnetic, rock magnetic, and geochemical data on C and O stable isotopes. The 87Sr/86Sr values of limestones increase upward the section: from 0.70741 to 0.70752 in Aksu-Dere and from 0.70750 to 0.70755 in Kudrino-2. On the basis of the results, the outcrops are correlated and the Kudrino–Aksu-Dere composite section is compilled, in which we identified paleontological, paleomagnetic, and isotopic markers necessary for the identification of the Santonian–Campanian boundary. The biostratigraphic boundaries are calibrated against the geomagnetic reversal 34n–33r and the SCBE isotopic event; thus, the base of the Campanian Stage should be determined by the base of the Chron 33r. In the volume of the geological record of the Santonian–Campanian boundary, saturation in guide fossil forms, and complex study, the composite section matches the candidates for a Global Boundary Stratotype Section and Point of the Campanian in North Texas and Southern England. This allows us to propose it as one of the candidates of the stratotype or an auxiliary section of the lower boundary of the Campanian Stage. [ABSTRACT FROM AUTHOR]