Radiometric Dating

放射性约会
  • 文章类型: Journal Article
    基于人工制品类型的时间框架对于解释考古记录至关重要,但是他们无意中将阶段之间的过渡视为突然事件,并忽略了各个阶段内部和之间的转换过程的时间性。这项研究提供了对丹麦铁器时代早期火田的动态物质文化的绝对时间顺序调查。斯堪的纳维亚南部早期铁器时代的时间顺序框架在很大程度上不受绝对约会的约束,主要是由于它与所谓的“Hallstatt校准平台”(c.750至400calBC)相吻合,由于缺乏进口的人工制品,很难将其与中欧的年表相关联。这项研究应用了放射性碳测年和贝叶斯时间顺序建模的最新方法学进展,特别是火化骨骼中木材年龄偏移的统计模型,并介绍了南日德兰半岛铁器时代早期区域物质文化的首次大规模放射性碳调查,丹麦。日期材料主要是来自三个火田的111个火葬墓葬中的火化骨头。该研究提出了16种陶器和15种金属制品的绝对日期范围,其中包括该时期大多数公认的金属制品类型。这为物质文化的逐渐变化提供了新的见解,当某些人工制品类型在生产和初级使用时,类型被吸收和后来被放弃的速度有多快,区分变化较快和较慢的时期。该研究还提供了该时期的第一个绝对年表,实现与其他地区的时间顺序的相关性。乌恩菲尔德是在青铜时代-铁器时代转型时引入的,这通常被认为发生在公元前530-500年。我们证明了这种转变发生在公元前7世纪,然而,重新讨论了是否应将最后的青铜时代VI期解释为铁器时代的过渡阶段。
    Chronological frameworks based on artefact typologies are essential for interpreting the archaeological record, but they inadvertently treat transitions between phases as abrupt events and disregard the temporality of transformation processes within and between individual phases. This study presents an absolute chronological investigation of a dynamic material culture from Early Iron Age urnfields in Denmark. The chronological framework of Early Iron Age in Southern Scandinavia is largely unconstrained by absolute dating, primarily due to it coinciding with the so-called \'Hallstatt calibration plateau\' (c.750 to 400 cal BC), and it is difficult to correlate it with Central European chronologies due to a lack of imported artefacts. This study applies recent methodological advances in radiocarbon dating and Bayesian chronological modelling, specifically a statistical model for wood-age offsets in cremated bone and presents the first large-scale radiocarbon investigation of regional material culture from Early Iron Age in Southern Jutland, Denmark. Dated material is primarily cremated bone from 111 cremation burials from three urnfields. The study presents absolute date ranges for 16 types of pottery and 15 types of metalwork, which include most of the recognised metalwork types from the period. This provides new insights into gradual change in material culture, when certain artefact types were in production and primary use, how quickly types were taken up and later abandoned, and distinguishing periods of faster and slower change. The study also provides the first absolute chronology for the period, enabling correlation with chronologies from other regions. Urnfields were introduced at the Bronze-Iron Age transformation, which is often assumed to have occurred c.530-500 BC. We demonstrate that this transformation took place in the 7th century BC, however, which revives the discussion of whether the final Bronze Age period VI should be interpreted as a transitional phase to the Iron Age.
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  • 文章类型: Historical Article
    大量的放射性碳数据越来越多地用作推断过去人口动态和过去几年的代理,特别是,新统计技术的发展有所增加,以克服此类数据带来的一些关键挑战。其中包括:1)基于蒙特卡洛模拟或标记排列的零假设显著性检验方法;2)非参数贝叶斯建模方法,3)使用更传统的技术,如相关性,回归,和基于AIC的模型直接比较放射性碳数据(SPD)的总概率分布。虽然这些解决方案提供的机会范围无疑具有吸引力,他们通常不考虑校准效应或抽样误差引起的不确定性和偏差。在这里,我们介绍了一种新的贝叶斯方法和nimbleCarbon,一个R包,根据放射性碳数据的时间频率数据,为人口增长模型提供模型拟合和比较。我们评估了所提出的方法在一系列模拟场景中的稳健性,并说明了其在一个案例研究中的应用,该案例研究的重点是在公元前1千年期间在史前日本引入湿水稻种植对人口的影响。
    Large sets of radiocarbon dates are increasingly used as proxies for inferring past population dynamics and the last few years, in particular, saw an increase in the development of new statistical techniques to overcome some of the key challenges imposed by this kind of data. These include: 1) null hypothesis significance testing approaches based on Monte-Carlo simulations or mark permutations; 2) non-parametric Bayesian modelling approaches, and 3) the use of more traditional techniques such as correlation, regression, and AIC-based model comparison directly on the summed probability distribution of radiocarbon dates (SPD). While the range of opportunities offered by these solutions is unquestionably appealing, they often do not consider the uncertainty and the biases arising from calibration effects or sampling error. Here we introduce a novel Bayesian approach and nimbleCarbon, an R package that offers model fitting and comparison for population growth models based on the temporal frequency data of radiocarbon dates. We evaluate the robustness of the proposed approach on a range of simulated scenarios and illustrate its application on a case study focused on the demographic impact of the introduction of wet-rice farming in prehistoric Japan during the 1st millennium BCE.
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  • 文章类型: Journal Article
    The early peopling of the Americas has been one of the most hotly contested topics in American anthropology and a research issue that draws archaeologists into a multidisciplinary debate. In South America, although the background data on this issue has increased exponentially in recent decades, the core questions related to the temporal and spatial patterns of the colonization process remain open. In this paper we tackle these questions in the light of the quantitative analysis of a screened radiocarbon database of more than 1600 early dates. We explore the frequency of radiocarbon dates as proxies for assessing population growth; and define a reliable and statistically well supported lower chronological bound (not to the exact date) for the earliest human arrival. Our results suggest that the earliest chronological threshold for the peopling of South America should be between 16,600 and 15,100, with a mean estimated date ~ 15,500 cal BP (post Last Glacial Maximum). Population would have grown until the end of Antarctic Cold Reversal stadial ~12,500 cal BP at the time of the main extinctions of megafauna-, when the increase rate slows, probably as a result of the changes that occurred in the trophic niche of humans.
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  • 文章类型: Historical Article
    Seemingly empty spaces in various archaeological settings have left many unanswered questions. This paper focuses on the appearance, maintenance and possible function of a large empty area situated at the summit plateau of the Iron Age oppidum Bibracte in France. Multidisciplinary research of the infill of the ditch that delimited this area in the 1st century BC has provided evidence on the primary function and the formation processes of the structure itself, and for the reconstruction of the appearance, maintenance and function of the area it enclosed. The results allow us to gain insight into a variety of topics, including the role of trees, hygiene measures and waste management strategies at this urbanised hilltop centre. This paper demonstrates that multi-proxy analyses provide detailed insight into the function of archaeological features in a local environmental context and the potential of such approaches in archaeology.
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  • 文章类型: Journal Article
    Theoretical and experimental studies have shown that activity concentrations of fallout radionuclides (such as 137Cs and excess 210Pb) decrease with particles size in aqueous suspensions. This paper is aimed at reviewing the theoretical fundamentals for granulometric speciation of radionuclides, and at exploring its practical use in the analytical context of gamma spectrometry for the radiometric dating of recent sediments, with view to: i) improving the detection of 137Cs (since its use as independent chronostratigraphic mark is challenging in the southern hemisphere because its low fallout rate), ii) supporting refined CIC models and normalization techniques in 210Pb-based radiogeochronologies. The work uses surface sediments sampled from the Tinto Estuary (SW Spain), affected by mining and phosphate-fertilizer industries, and from the Ankobra Estuary (Ghana), affected by intensive artisanal gold-mining. Granulometric classes have been separated by a sieving column with decreasing mesh sizes and the obtained cumulative percentage of mass mathematically described by a Rosin-Rammler particle-size distribution. The target radionuclides for gamma spectrometry were 210Pb, 226Ra and137Cs, complemented with 40K, 234Th and 228Ra. Results revealed that, far from ideal experiments, under actual environmental conditions the increase in activity concentrations with decreasing particle sizes is too moderate, and in general they are affected by larger counting uncertainties due to the small available amount of mass. Indeed, there was no correlation between grain-size and 137Cs concentrations (p = 0.25), and similarly for excess 210Pb (p = 0.53). No effect of the organic matter content was observed in 137Cs (p = 0.58) and excess 210Pb (p = 0.85) concentrations. Present results pose some concerns to the general use of granulometric speciation in the context of gamma spectrometry for supporting the radiometric dating of recent sediments. A detailed discussion on the use of normalization methods is also presented.
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  • 文章类型: Biography
    雅克·德·维特里的圣物,13世纪初的著名神职人员和神学家,在过去的几个世纪里经历了几次转移,严重质疑遗骸对已故红衣主教的归属。关于他出生年份的不确定性对他在1240年去世时的年龄提出了另一个问题。圣物,位于SaintMaried\'Oigines教堂,比利时,在2015年重新开放,围绕他的遗物以及Oignies的宝藏进行跨学科研究,这是一个非凡的文化遗产,尤其是雅克·德·维特里的捐赠。人类学,同位素和遗传分析是对遗骸中发现的遗骸独立进行的。分析结果提供的证据表明,这些遗骸是雅克·德·维特里遗骸的可能性非常高:这些遗骸属于同一人类男性个体,并且关于他年龄的历史传统得到了证实。此外,分析了一个单独的遗物(左胫骨),发现与遗物(右胫骨)的遗物相匹配。雅克·德·维特里独特的斜线,羊皮纸做的,进行无损采样,并通过蛋白质组学方法分析提取的羊皮纸胶原蛋白以确定动物物种。结果表明,令人惊讶的是,并非所有的斜接部分都是由同一物种制成的。一起,这些发现有望为雅克·德·维特里及其相关文化遗产的历史传统提供知识。
    The reliquary of Jacques de Vitry, a prominent clergyman and theologian in the early 13th century, has experienced several transfers over the last centuries, which seriously question the attribution of the remains to the late Cardinal. Uncertainty about the year of his birth poses an additional question regarding his age at death in 1240. The reliquary, located in the Saint Marie d\'Oigines church, Belgium, was reopened in 2015 for an interdisciplinary study around his relics as well as the Treasure of Oignies, a remarkable cultural heritage notably built from Jacques de Vitry\'s donation. Anthropological, isotopic and genetic analyses were performed independently on the remains found in the reliquary. Results of the analyses provided evidence that the likelihood that these remains are those of Jacques de Vitry is very high: the remains belong to the same human male individual and the historical tradition about his age is confirmed. In addition, a separate relic (left tibia) was analysed and found to match with the remains of the reliquary (right tibia). The unique Jacques de Vitry\'s mitre, made of parchment, was sampled non-destructively and the extracted parchment collagen was analysed by a proteomic method in order to determine the animal species. The results showed that, surprisingly, not all parts of the mitre were made from the same species. All together, these findings are expected to fertilize knowledge carried by historical tradition around the relics of Jacques de Vitry and his related cultural heritage.
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  • 文章类型: Journal Article
    Data on modern radiocarbon activity in the old travertine formations of the Pymvashor hydrothermal system were used, in combination with 230Th/U dating of the travertine, to estimate the 14C contents of the total dissolved inorganic carbon in the ancient thermal water at the time of precipitation of the travertine (14Ccalc). With the known values of 14Ccalc and average age of the thermal water, and under the assumption that the residence time of the water in aquifer was constant over the last 13.9 ± 1.5 ka, the initial 14C contents (14C0) in the ancient thermal water were estimated. The findings in this study are that (1) both 14C0 and δ13С have decreased in young waters compared to the ancient waters; (2) although atmospheric 14C activity (14Catm) has also decreased in the same time, the decrease in 14C0 is faster than the decrease in 14Catm. Under certain assumptions, one could link changes in 14C0 and δ13C to climate change. Decrease in δ13С of soil CO2 and decrease in 14C0 was caused predominantly by warmer and wetter climate, decomposition of fossil organic matter, and decrease in 14Catm. There could be also increased dissolution of solid carbonate and increased carbon exchange between DIC and soil CO2, caused by thawing permafrost.
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  • 文章类型: Journal Article
    Sea level rise and the associated inland shift of the marsh-mangrove ecotone in south Florida have raised many scientific and management concerns in recent years. Holocene paleoecological records can provide an important baseline to shed light on the long-term dynamics of vegetation changes across this ecotone in the past, which is needed to predict the future. In this study, we present palynological, X-ray fluorescence, and loss-on ignition data from four sedimentary cores recovered from a 20-km marine-to-freshwater transect along the Shark River Estuary, southwest Everglades, to document the patterns and processes of coastal vegetation changes in response to sea level rise since the mid-Holocene. Our record indicates that freshwater marsh progressively replaced marl prairies at the Shark River Estuary between 5700 and 4400 cal yr BP. As marine transgression continued, marine influence reached the threshold necessary for mangroves to establish at the current mouth of the Shark River Slough at 3800 cal yr BP. During the next 3000 years, although sea level rise in the Western North Atlantic slowed down to 0.4 mm/yr, a spatial and temporal gradient was evident as the marsh-mangrove ecotone shifted inland by 20 km from 3800 to 800 cal yr BP, accompanied by a gradual landward replacement of freshwater marsh by mangrove forest. If sea level continues to rise at 2.33 mm/yr in the 21st century in south Florida, it is possible that marine influence will reach the threshold for mangroves to establish in the central Everglades, and we could expect a much more aggressive mangrove encroachment toward the northern and interior parts of south Florida in the next few centuries.
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  • 文章类型: Historical Article
    Investigation of mortuary ritual is an important method to reconstruct many aspects of past societies. Due to the lack of relevant analytical work, little evidence related to organic materials in a burial can be found in China. Here we report materials collected from a burial during the excavation of the Shengedaliang site. The recovered materials were analyzed using Raman spectroscopy and plant analysis: flotation, pollen and phytolith analysis. The red pigments found scattered over the human remains were identified as cinnabar. Extracted phytoliths associated with the burial are mainly leaves from the Boraginaceae family. This is the first time that a covering of leaves have been identified with a burial in Neolithic China. The presence of \"special\" leaves fossil may indicate a type of \"plant worship\" and the identification of an important plant used in traditional Chinese medicine. The finding of the two materials allows us to better identify indicators of funerary ritual and its relationship to social inequality.
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  • 文章类型: Journal Article
    Skeletal dysplasias related to genetic etiologies have rarely been reported for past populations. This report presents the skeletal characteristics of an individual with dwarfism-related skeletal dysplasia from South Korea. To assess abnormal deformities, morphological features, metric data, and computed tomography scans are analyzed. Differential diagnoses include achondroplasia or hypochondroplasia, chondrodysplasia, multiple epiphyseal dysplasia, thalassemia-related hemolytic anemia, and lysosomal storage disease. The diffused deformities in the upper-limb bones and several coarsened features of the craniofacial bones indicate the most likely diagnosis to have been a certain type of lysosomal storage disease. The skeletal remains of EP-III-4-No.107 from the Eunpyeong site, although incomplete and fragmented, provide important clues to the paleopathological diagnosis of skeletal dysplasias.
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