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1. Non Nok Tha Radiocarbon Compendium

   https://doi.org/10.25827/kp8t-bw37  

   Conrad, Cyler; Green, Ernestene (January 2020, University of New Mexico)

   {"Abstract":["This compendium includes five documents: 1) the "Buckley Letter" describing the radiocarbon analysis results for sample I-5324, 2) the "GaK-1026" sheet describing the radiocarbon analysis results for sample GaK-1026, 3) the "Geochron Letter" describing radiocarbon analysis results for sample GX-1612, 4) Ernestene Green's ca. 1965 field notes on her test excavations at Non Nok Tha, and 5) the "UGAMS Letter" describing the radiocarbon analysis results and methods for this study: Conrad, C. and E. Green. in prep. New Radiocarbon Dates from Non Nok Tha (Partridge Mound), Khon Kaen Province, Northeast Thailand. Archaeological Research in Asia.\n\nNon Nok Tha, Radiocarbon, Thailand, Khorat Plateau, Gakushuin Laboratory"]} 

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2. Multi-Level Radiocarbon Analysis of Hawaiian SOC

   Grant, K.; Galy, V.; Haghipour, N.; Eglinton, T.; Derry, L. (January 2018, Annual VM Goldschmidt Conference)

   Grant Goldschmidt 2018 

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3. RADIOCARBON RESERVOIR AGES IN THE HOLOCENE DEAD SEA

   https://doi.org/10.1017/RDC.2020.28  

   Weber, Nurit; Lazar, Boaz; Stern, Ofra; Burr, George; Gavrieli, Ittai; Roberts, Mark; Kurz, Mark D; Yechieli, Yoseph; Stein, Mordechai (October 2020, Radiocarbon)

   null (Ed.)

   ABSTRACT The sources and fate of radiocarbon ( 14 C) in the Dead Sea hypersaline solution are evaluated with 14 C measurements in organic debris and primary aragonite collected from exposures of the Holocene Ze’elim Formation. The reservoir age (RA) is defined as the difference between the radiocarbon age of the aragonite at time of its precipitation (representing lakeʼs dissolved inorganic carbon [DIC]) and the age of contemporaneous organic debris (representing atmospheric radiocarbon). Evaluation of the data for the past 6000 yr from Dead Sea sediments reveal that the lakeʼs RA decreased from 2890 yr at 6 cal kyr BP to 2300 yr at present. The RA lies at ~2400 yr during the past 3000 yr, when the lake was characterized by continuous deposition of primary aragonite, which implies a continuous supply of freshwater-bicarbonate into the lake. This process reflects the overall stability of the hydrological-climate conditions in the lakeʼs watershed during the late Holocene where bicarbonate originated from dissolution of the surface cover in the watershed that was transported to the Dead Sea by the freshwater runoff. An excellent correlation (R 2 =0.98) exists between aragonite ages and contemporaneous organic debris, allowing the estimation of ages of various primary deposits where organic debris are not available. 

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4. Culture Process and the Interpretation of Radiocarbon Data

   https://doi.org/10.1017/RDC.2017.124  

   Freeman, Jacob; Byers, David A; Robinson, Erick; Kelly, Robert L (April 2018, Radiocarbon)

   Abstract Over the last decade, archaeologists have turned to large radiocarbon ( 14 C) data sets to infer prehistoric population size and change. An outstanding question concerns just how direct of an estimate 14 C dates are for human populations. In this paper we propose that 14 C dates are a better estimate of energy consumption, rather than an unmediated, proportional estimate of population size. We use a parametric model to describe the relationship between population size, economic complexity and energy consumption in human societies, and then parametrize the model using data from modern contexts. Our results suggest that energy consumption scales sub-linearly with population size, which means that the analysis of a large 14 C time-series has the potential to misestimate rates of population change and absolute population size. Energy consumption is also an exponential function of economic complexity. Thus, the 14 C record could change semi-independent of population as complexity grows or declines. Scaling models are an important tool for stimulating future research to tease apart the different effects of population and social complexity on energy consumption, and explain variation in the forms of 14 C date time-series in different regions. 

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5. Dimensions of Radiocarbon Variability within Sedimentary Organic Matter

   https://doi.org/10.1017/RDC.2018.22  

   Bao, Rui; McNichol, Ann P; McIntyre, Cameron P; Xu, Li; Eglinton, Timothy I (June 2018, Radiocarbon)

   ABSTRACT Organic carbon (OC) radiocarbon ( 14 C) signatures in marine surface sediments are highly variable and the causes of this heterogeneity remain ambiguous. Here, we present results from a detailed 14 C-based investigation of an Arabian Sea sediment, including measurements on organic matter (OM) in bulk sediment, specific grain size fractions, and OC decomposition products from ramped-pyrolysis-oxidation (RPO). Our results show that 14 C ages of OM increase with increasing grain size, suggesting that grain size is an important factor controlling the 14 C heterogeneity in marine sediments. Analysis of RPO decomposition products from different grain size fractions reveals an overall increase in age of corresponding thermal fractions from finer to coarser fractions. We suggest that hydrodynamic properties of sediment grains exert the important control on the 14 C age distribution of OM among grain size fractions. We propose a conceptual model to account for this dimensionality in 14 C variability that invokes two predominant modes of OM preservation within different grain size fractions of Arabian Sea sediment: finer (<63 µm) fractions are influenced by OM-mineral grain aggregation processes, giving rise to relatively uniform 14 C ages, whereas OM preserved in coarser (>63 µm) fractions includes materials encapsulated within microfossils and/or entrained fossil ( 14 C-depleted) OC hosted in detrital mineral grains. Our findings highlight the value of RPO for assessment of 14 C age variability in sedimentary OC, and for assessing mechanisms of OM preservation in aquatic sediments. 

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