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1.	Blaauw, Maarten, et al. (författare) A Bayesian framework for age-modelling of radiocarbon-dated peat deposits: case studies from the Netherlands 2007 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 49:2, s. 357-367 Tidskriftsartikel (refereegranskat)abstract Recently, Bayesian statistical software has been developed for age-depth modeling (“wiggle-match dating”) ofsequences of densely spaced radiocarbon dates from peat cores. The method is described in non-statistical terms, and is com-pared with an alternative method of chronological ordering of 14C dates. Case studies include the dating of the start of agri-culture in the northeastern part of the Netherlands, and of a possible Hekla-3 tephra layer in the same country. We discussfuture enhancements in Bayesian age modeling.
2.	Bonsall, Clive, et al. (författare) Food for Thought : Re-Assessing Mesolithic Diets in the Iron Gates 2015 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 57:4, s. 689-699 Tidskriftsartikel (refereegranskat)abstract Stable isotope ratios of carbon, nitrogen, and sulfur in human bone collagen are used routinely to aid in the reconstruction of ancient diets. Isotopic analysis of human remains from sites in the Iron Gates section of the Lower Danube Valley has led to conflicting interpretations of Mesolithic diets in this key region of southeast Europe. One view (Bonsall et al. 1997, 2004) is that diets were based mainly on riverine resources throughout the Mesolithic. A competing hypothesis (Nehlich et al. 2010) argues that Mesolithic diets were more varied with at least one Early Mesolithic site showing an emphasis on terrestrial resources, and riverine resources only becoming dominant in the Later Mesolithic. The present article revisits this issue, discussing the stable isotope data in relation to archaeozoological and radiocarbon evidence.
3.	Dury, Jack P. R., et al. (författare) CONSIDERATION OF FRESHWATER AND MULTIPLE MARINE RESERVOIR EFFECTS : DATING OF INDIVIDUALS WITH MIXED DIETS FROM NORTHERN SWEDEN 2018 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 60:5, s. 1561-1585 Tidskriftsartikel (refereegranskat)abstract Human burials from the cemetery at the Rounala church, northern Sweden, were radiocarbon (C-14) dated to shed light on the use of the cemetery. Carbon, nitrogen and sulfur stable isotope analysis of bone collagen from 19 distinct individuals indicated that these individuals had a mixed diet consisting of freshwater, marine and terrestrial resources. Dietary modeling using FRUITS was employed to calculate the contributions of the different resources for each individual. These data were then used to calculate individual Delta R values, taking into account freshwater and multiple marine reservoir effects, the latter caused by Baltic and Atlantic marine dietary inputs, respectively. C-14 dating of tissues from modern freshwater fish species demonstrate a lack of a freshwater reservoir effect in the area. Two OxCal models were used to provide endpoint age estimates. The calibrated data suggest that the site's cemetery was most likely in use already from the 14th century, and perhaps until at least the late 18th century.
4.	Eilers, Gerriet, et al. (författare) The Radiocarbon Intracavity Optogalvanic Spectroscopy Setup at Uppsala 2013 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 55:3-4, s. 237-250 Tidskriftsartikel (refereegranskat)abstract Accelerator mass spectrometry (AMS) is by far the predominant technology deployed for radiocarbon tracer studies. Applications are widespread from archaeology to biological, environmental, and pharmaceutical sciences. In spite of its excellent performance, AMS is expensive and complicated to operate. Consequently, alternative detection techniques for 14C are of great interest, with the vision of a compact, user-friendly, and inexpensive analytical method. Here, we report on the use of intracavity optogalvanic spectroscopy (ICOGS) for measurements of the 14C/12C ratio. This new detection technique was developed by Murnick et al. (2008). In the infrared (IR) region, CO2 molecules have strong absorption coefficients. The IR-absorption lines are narrow in line width and shifted for different carbon isotopes. These properties can potentially be exploited to detect 14CO2, 13CO2, or 12CO2 molecules unambiguously. In ICOGS, the sample is in the form of CO2 gas, eliminating the graphitization step that h is required in most AMS labs. The status of the ICOGS setup in Uppsala is presented. The system is operational but not yet fully developed. Data are presented for initial results that illustrate the dependence of the optogalvanic signal on various parameters, such as background and plasma-induced changes in the sample gas composition.
5.	Fontana, Sonia L. (författare) Radiocarbon chronologies of Holocene lacustrine sediments from the southern coast of Buenos Aires Province, Argentina 2007 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 49:1, s. 103-116 Tidskriftsartikel (refereegranskat)abstract Two lacustrine sediment sequences, La Olla 1 and Laguna del Sauce Grande, on the southern coast of Buenos Aires Province, Argentina, were investigated for carbon reservoir effects, which may influence age-depth chronologies. Fruits of the submerged macrophyte Ruppia cf. maritima from the La Olla 1 sequence, and gastropod shells of Heleobia parchappii from the Laguna del Sauce Grande core, were radiocarbon dated. In addition, terrestrial plant remains and shells of living specimens were dated to assess the presence and magnitude of a reservoir effect. A reservoir age of about 800 14C yr is estimated for the aquatic plant samples of La Olla 1 for the early Holocene. The reservoir effect is attributed to the inwash of 14C-deficient bicarbonate from the surrounding sand dunes. The decay of marine organisms and salt spray are likely the main sources of 14C-deficient carbon. The magnitude of the reservoir effect is consistent with marine reservoir offsets reported for the region. The 14C measurements on shells of living and fossil specimens of Heleobia parchappii indicate the absence of a reservoir effect at Laguna del Sauce Grande, which may be due to the large size and shallow nature of the lake. This study shows how the reservoir ages of 2 close-by lakes in very similar geological settings can be largely different. These results have significant implications for the interpretation of 14C dates from lacustrine deposits in the region.
6.	Larsson, Anton, 1994-, et al. (författare) Jordfallet at Bohus : Reinterpreting the 14C dating of a medieval landslide event 2022 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 64:5, s. 1239-1255 Tidskriftsartikel (refereegranskat)abstract Radiocarbon (14C) dating has, since its inception, become an integral part of disciplines such as geology and archaeology, underpinning many key findings made by researchers in the past seven decades. As 14C dating develops, the need arises to revisit older findings and legacy data which may well contain laboratory errors or post-analysis misinterpretations. In this paper we examine one such finding from Sweden, namely the 1958 14C dating of the great Jordfallet (“the Earthfall”) landslide, which was published in the very first volume of Radiocarbon in 1959. We further trace how the results of this 14C dating were misunderstood in a time prior to modern radiocarbon calibration, and the impact which this mistake has had throughout academic publications, state reports and local heritage literature through the course of over sixty years. Because of this flawed interpretation the credible date of 1249 AD given to the landslide by historical sources has been overlooked. Instead, a series of dates from the mid-12th and early 13th centuries have been attributed to the landslide event based on erroneous radiocarbon analysis, a mistake which has substantial implications for the understanding of both regional and international history in medieval Scandinavia.
7.	Levin, Maureece J., et al. (författare) A Partial Chronological Sequence of Human Habitation for Pingelap Atoll (Pohnpei State, Federated States of Micronesia) 2019 Ingår i: Radiocarbon. - : UNIV ARIZONA DEPT GEOSCIENCES. - 0033-8222 .- 1945-5755. ; 61:3, s. 765-776 Tidskriftsartikel (refereegranskat)abstract Pingelap Atoll, 1.8 km(2) in area and nearly 70 km from the nearest island, presents a clear example of anthropogenic niche-building in physically isolated circumstances with limited resources. This paper presents the first radiocarbon (C-14) dates (n=8) from an archaeological project examining settlement and subsistence practices on the atoll, specifically how Pingelapese people have constructed the environment to meet their needs over centuries of occupation. These dates confirm that human occupation of Pingelap occurred by 1700-1550 cal BP (2 sigma) at the latest, only a few centuries after the earliest securely-dated settlement of high islands in the region (Kosrae and Pohnpei), and with strikingly similar timing to another atoll in the region, Mwoakilloa. Evidence of early settlement includes shell tools, ornaments, extensive marine faunal remains, and charred botanical domesticates. These preliminary data build a framework for the settlement history and environment building of Pingelap.
8.	Lillie, Malcolm, 1963-, et al. (författare) Factors influencing the radiocarbon dating of human skeletal remains from the Dnieper river system : Archaeological and stable isotope evidence of diet from the Epipalaeolithic to Eneolithic periods 2016 Ingår i: Radiocarbon. - : Oxford University Press. - 0033-8222 .- 1945-5755. ; 58:4, s. 741-753 Tidskriftsartikel (refereegranskat)abstract Recent research has identified the existence of a freshwater reservoir effect influencing the radiocarbon dating of human skeletal remains from the Dnieper region of Ukraine (Lillie et al. 2009). The current study outlines the evidence for freshwater resource exploitation throughout the period ~10,200–3700 cal BC, and presents the available evidence for the existence of dietary offsets in the 14C dates obtained. We have obtained human skeletal material from 54 Epipaleolithic to Mesolithic period individuals and 267 Neolithic to Eneolithic individuals, from 13 cemeteries, since our research in Ukraine began in 1992. Here, we present the initial results of stable isotope analysis of Eneolithic individuals from the Igren VIII cemetery alongside the Epipaleolithic to Eneolithic samples that have previously been analyzed. When contrasted against the evidence from the prehistoric fauna and fish remains studied, and modern fish species from the Dnieper region, we continue to see variability in diets at the population level, both internally and across cemeteries. We also observed temporal variability in human diets across these chronological periods. The fish samples (both archaeological and modern) show a wide range of isotope ratios for both δ13C and δ15N, which could prove significant when interpreting the dietary sources being exploited. This information directly informs the 14C dating program as an inherent degree of complexity is introduced into the dating of individuals whose diets combine freshwater and terrestrial sources in differing quantities and at differing temporal and/or spatial scales (e.g. Bronk Ramsey et al. 2014)
9.	Lougheed, Bryan C., 1982- (författare) USING SEDIMENTOLOGICAL PRIORS TO IMPROVE C-14 CALIBRATION OF BIOTURBATED SEDIMENT ARCHIVES 2022 Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 64:1, s. 135-151 Tidskriftsartikel (refereegranskat)abstract Radiocarbon (C-14) dating is often carried out upon multi-specimen samples sourced from bioturbated sediment archives, such as deep-sea sediment. These samples are inherently heterogeneous in age, but existing C-14 calibration techniques were originally developed for age homogeneous material, such as archaeological artifacts or individual tree rings. A lack of information about age heterogeneity leads to a systematic underestimation of a sample's true age range, as well as the possible generation of significant age-depth artifacts during periods of the Earth's history coinciding with highly dynamic atmospheric Delta C-14. Here, a new calibration protocol is described that allows for the application of sedimentological priors describing sediment accumulation rate, bioturbation depth and temporally dynamic species abundance. This Bayesian approach produces a credible calibrated age distribution associated with a particular laboratory C-14 determination and its associated sedimentological priors, resulting in an improved calibration, especially in the case of low sediment accumulation rates typical of deep-sea sediment. A time-optimized computer script (biocal) for the new calibration protocol is also presented, thus allowing for rapid and automated application of the new calibration protocol. This new calibration protocol could be applied within existing age-depth modeling software packages to produce more accurate geochronologies for bioturbated sediment archives.
10.	Mellström, Anette, et al. (författare) Radiocarbon wiggle-matching of bulk sediments - how accurate can it be? 2013 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 55:2-3, s. 1173-1186 Tidskriftsartikel (refereegranskat)abstract We used the radiocarbon wiggle-match dating technique to date the varved sediments of Lake Gyltigesjön in southern Sweden with the main aim to construct an accurate chronology covering the period between about 3000 and 2000 cal BP. Wiggle-match dating was applied to bulk sediments to evaluate the possibility of constructing accurate chronologies in the absence of terrestrial plant macrofossils and when the amount of old carbon in the sediments is unknown. Facilitated by a floating varve chronology and relatively stable 14C reservoir ages, the results show the possibility to assess the contribution of old carbon solely based on the 14C wiggle-matching of bulk sediments. We confirm the wiggle-matched chronology and the 14C reservoir age of approximately 260 yr by cross-checking the results with 14C dating of macrofossils. The obtained calibrated ages based on bulk sediments have an uncertainty range of about 60–65 yr (95.4% confidence interval). This study confirms that 14C wiggle-match dating of bulk sediments is a viable tool when constructing high-resolution chronologies. The method is especially useful in Sun-climate studies since the timing between solar activity variations (expressed as 14C variations) and climate changes can be accurately determined.
11.	Missiaen, L., et al. (författare) Radiocarbon Dating of Small-Sized Foraminifer Samples : Insights into Marine sediment Mixing 2020 Ingår i: Radiocarbon. - : UNIV ARIZONA DEPT GEOSCIENCES. - 0033-8222 .- 1945-5755. ; 62:2, s. 313-333 Tidskriftsartikel (refereegranskat)abstract Radiocarbon (C-14) can be used to build absolute chronologies and reconstruct ocean ventilation over the last 40 ka. Sample size requirements have restricted C-14 measurements in marine cores with low foraminifer content, impeding C-14-based studies focused on abrupt climate events. Recent developments have demonstrated that small-sized foraminifer samples can now be dated using a gas introduction system at the cost of a small decrease in precision. We explore the potential of gas measurements on benthic and planktonic foraminifers from core SU90-08 (43 degrees 03'1 '' N, 30 degrees 02'5 '' W, 3080 m). Gas measurements are accurate, reproducible within 2 sigma uncertainty and comparable to graphite measurements. Both techniques yield negative C-14 benthic-planktonic (B-P) age-offsets after Heinrich event 1. We argue that negative B-P ages result from bioturbation and changes in foraminifer abundances, with the chance of negative B-P especially increased when the C-14 age gradient between the deep and surface waters is decreased. Small-sized C-14 measurements seem to capture the variance of the foraminifera age distribution, revealing the active mixing in those archives. Sediment deposition and mixing effects possibly pose a greater obstacle for past C-14-based dating and ocean ventilation reconstructions than the measurement precision itself, particularly in relatively low sedimentation rate settings.
12.	Olsson, Ingrid U. (författare) Radiocarbon Dating History : Early Days, Questions, and Problems Met 2009 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 51:1, s. 1-43 Forskningsöversikt (refereegranskat)abstract W F Libby's new dating method from the 1940s, based on experience in physics and chemistry, opened possibilities to check and revise chronologies built on other principles than radioactive decay. Libby's method initially implied collaboration with archaeologists to demonstrate that it worked but also with physicists to improve the technique to measure low beta-activities. Chemists, geophysicists, botanists, physiologists, statisticians, and other researchers have contributed to a prosperous interdisciplinary development. Some pitfalls were not recognized from the beginning, although issues such as contamination problems were foreseen by Libby. Pretreatment of samples was discussed very early by de Vries and collaborators. among others. This subject has not yet been abandoned. Closely related to pretreatment is the choice of fraction to be dated and chemicals to be used, especially for accelerator mass spectrometry(AMS) measurements. Calibration against tree rings and comparison with dates obtained using other methods as well as intercomparison projects are partly history but still very actual. The impact by man and climate is also studied since the early days of the method. Also, the carbon cycle has been of great interest. The tools for measurements and statistical analysis have been improved during these first 3 or 4 decades, allowing interpretations not possible earlier. delta C-13 determinations are mostly very important and useful, but sometimes they have been misleading in discussions of the origin of carbon. especially for human tissues-the metabolism was not yet fully understood. The history and development of the method can only be illustrated by selected examples in a survey like this.
13.	Peyroteo Stjerna, Rita, 1977- (författare) Chronology of the burial activity of the last hunter-gatherers in the southwestern Iberian Peninsula, Portugal 2021 Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 63:1, s. 265-299 Tidskriftsartikel (refereegranskat)abstract For most of human history, funerary burial has been unusual. Archaeology shows a shift in funerary practices in postglacial hunter-gatherers, in parts of Europe during the Late Mesolithic. This is documented by the burial grounds in the Tagus and Sado valleys in the southwestern Iberian Peninsula, Portugal, where ca. 376 burials were excavated. This study presents a chronology for the burial activity in these sites and contextualizes the start and end activity phases within regional environmental changes and cultural developments. The dataset consists of 76 14C dates on human bone (19 new, 57 published) including new dates from contexts in Portugal outside these valleys. Bayesian chronological models were defined in OxCal, and protein carbon contributions of marine foods were estimated by the Bayesian mixing model FRUITS. The results indicate a broader timeframe for the Late Mesolithic in Portugal, than previously suggested, starting during a period of significant environmental changes, ca. 8500–8300 cal BP, and ending ca. 7000 cal BP. The burial activity decreased during the establishment of Neolithic farmers in southwestern Iberia from ca. 7450 cal BP, however, these burial grounds continued to be used by Mesolithic hunter-gatherers, showing that diverse social structures and worldviews coexisted for several generations.
14.	Possnert, Göran, 1951-, et al. (författare) PROFESSOR INGRID ULRIKA OLSSON (1927-2018) : IN MEMORIAM 2022 Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 64:3, s. 459-461 Tidskriftsartikel (refereegranskat)
15.	Rodrigues, Luiz F, et al. (författare) Origin and alteration of organic matter in hydrate-bearing sediments of the Rio Grande Cone, Brazil : evidence from biological, physical, and chemical factors. 2020 Ingår i: Radiocarbon. - : Cambridge University Press. - 0033-8222 .- 1945-5755. ; 62:1, s. 197-206 Tidskriftsartikel (refereegranskat)abstract The Rio Grande Cone is a major fanlike depositional feature in the continental slope of the Pelotas Basin, Southern Brazil. Two representative sediment cores collected in the Cone area were retrieved using a piston core device. In this work, the organic matter (OM) in the sediments was characterized for a continental vs. marine origin using chemical proxies to help constrain the origin of gas in hydrates. The main contribution of OM was from marine organic carbon based on the stable carbon isotope (δ13C-org) and total organic carbon/total nitrogen ratio (TOC:TN) analyses. In addition, the 14C data showed important information about the origin of the OM and we suggest some factors that could modify the original organic matter and therefore mask the “real” 14C ages: (1) biological activity that could modify the carbon isotopic composition of bulk terrestrial organic matter values, (2) the existence of younger sediments from mass wasting deposits unconformably overlying older sediments, and (3) the deep-sediment-sourced methane contribution due to the input of “old” (>50 ka) organic compounds from migrating fluids.
16.	Salehpour, Mehran, 1960-, et al. (författare) Life science applications utilizing radiocarbon tracing 2013 Ingår i: Radiocarbon. - Tucson, Arizona, USA : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 55:2-3, s. 865-873 Tidskriftsartikel (refereegranskat)abstract Radiocarbon-based accelerator mass spectrometry (AMS) facilities at Uppsala University include a measurement center for archaeological applications and a separate entity dedicated to life science research. This paper addresses the latter, with the intention of giving a brief description of the biomedical activities at our laboratory, as well as presenting new data. The ultra-small sample preparation method, which can be used down to a few μg C samples, is outlined and complemented with new results. Furthermore, it is shown that the average secondary ion current performance for small samples can be improved by increasing the distance between the cathode surface and the pressed graphite surface. Finally, data is presented for a new application: Amyloidoses are a group of diseases where the conformational changes in specific proteins’ structure lead to the formation of extracellular deposits that spread and increase in mass and eventually may lead to total organ failure and death. The formation timeframe is unknown and yet it is an important clue for the elucidation of the mechanism. We present results on bomb-peak dating of 4 different types of purified amyloid proteins from human postmortem heart and spleen samples. The data indicates that the average measured age of the carbon originating from the systemic amyloid types studied here correspond to a few years before the death of the subject. This suggests that a major part of the fibril formation takes place during the last few years before death, rather than as an accumulation of amyloid deposits over decades.
17.	Schulz Paulsson, Bettina, 1970, et al. (författare) A Highly Precise Chronology for the Process of Neolithization in Southern Scandinavia: The ESS Project in Lund, Sweden 2017 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 59:2, s. 583-593 Tidskriftsartikel (refereegranskat)abstract In 2013, one of Sweden's largest archaeological excavations started in association with the building of the European Spallation Source (ESS) multidisciplinary research center in Lund. The 160 radiocarbon dates that were produced for the project represent the most exhaustive dating program for a Scandinavian site so far and provide evidence for the human impact and activities on the site from the Mesolithic to the Iron Age. This article presents the results within a Bayesian statistical framework for the 70 C-14 dates from the Early Neolithic settlement (object 1) and a burial site with dolmens and wooden faades. For the first time, a highly precise chronology provides deeper insight into the Neolithization processes and the early settlement strategies in southern Scandinavia from similar to 3800 cal BC onwards.
18.	Szidat, S., et al. (författare) Intercomparison of 14C Analysis of Carbonaceous Aerosols : Exercise 2009 2013 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222 .- 1945-5755. ; 55:2-3, s. 1496-1509 Tidskriftsartikel (refereegranskat)abstract Radiocarbon analysis of the carbonaceous aerosol allows an apportionment of fossil and non-fossil sources of airborne particulate matter (PM). A chemical separation of total carbon (TC) into its subfractions organic carbon (OC) and elemental carbon (EC) refines this powerful technique, as OC and EC originate from different sources and undergo different processes in the atmosphere. Although C-14 analysis of TC, EC, and OC has recently gained increasing attention, interlaboratory quality assurance measures have largely been missing, especially for the isolation of EC and OC. In this work, we present results from an intercomparison of 9 laboratories for C-14 analysis of carbonaceous aerosol samples on quartz fiber filters. Two ambient PM samples and 1 reference material (RM 8785) were provided with representative filter blanks. All laboratories performed C-14 determinations of TC and a subset of isolated EC and OC for isotopic measurement. In general, C-14 measurements of TC and OC agreed acceptably well between the laboratories, i.e. for TC within 0.015-0.025 (FC)-C-14 for the ambient filters and within 0.041 (FC)-C-14 for RM 8785. Due to inhomogeneous filter loading, RM 8785 demonstrated only limited applicability as a reference material for C-14 analysis of carbonaceous aerosols. C-14 analysis of EC revealed a large deviation between the laboratories of 28-79% as a consequence of different separation techniques. This result indicates a need for further discussion on optimal methods of EC isolation for C-14 analysis and a second stage of this intercomparison.
19.	Tóth, Peter, et al. (författare) Radiocarbin dating of grass-tempered ceramic reveals the earliest pottery from Slovakia predates the arrival of farming 2023 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 65:3, s. 733-753 Tidskriftsartikel (refereegranskat)abstract In the absence of wood, bone, and other organics, one possible candidate for determining the age of a site is the radiocarbon (14C) dating of pottery. In central Europe during the Early Neolithic, pottery was ubiquitous and contained substantial quantities of organic temper. However, attempts at the direct dating of organic inclusions raises a lot of methodological issues, especially when several sources of carbon contribute to the resulting radiocarbon age. Hence an alternative approach to dating of the early pottery is necessary. Here, we present a novel method of bulk separation of organic content from the grass-tempered pottery from Santovka (Slovakia). The procedure is based on the consecutive application of three inorganic acids, dissolving clay, silica content, and low molecular or mobile fractions to separate organic inclusions added to the pottery matrix during the formation of vessels. Radiocarbon dates obtained with this method are coherent and produce the shortest time span compared to other pretreatment methods presented in this study. The paired dates of grass-tempered pots with the 14C age of lipids extracted from the same pots point to a difference of 400–600 14C yr, however they are in line with the site’s chronostratigraphic Bayesian model. Grass-tempered pottery from Santovka (Slovakia) is dated to the first half of the 6th millennium cal BC, making it the earliest pottery north of the Danube. It seems feasible that ceramic containers from Santovka were produced by hunter-gatherers, and pottery predated the arrival of farming in the Carpathian region by a couple of centuries.
20.	Vybornov, A., et al. (författare) Chronological problems with neolithization of the northern caspian sea area and the forest-steppe povolzhye region 2012 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 54:3-4, s. 795-799 Tidskriftsartikel (refereegranskat)abstract Steppe and forest-steppe areas of the Povolzhye area (Caucasus and central Asia) bear much interest for the Neolithic in connection with the productive economy of the region at the time. Recent data have allowed correction of the region's chronology. A number of C-14 dates denote the existence of the Neolithic in this territory as early as the 5th to 6th millennium BP. However, some questions are still under debate and require further data to clarify.
21.	Zaitseva, G., et al. (författare) Radiocarbon dating of neolithic pottery 2009 Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 51:2, s. 795-801 Tidskriftsartikel (refereegranskat)abstract The direct measurement of organic matter included in archaeological pottery may yield a reliable assessment of age. The main problem consists in the identification of possible origins and assessment of distortion for the age of organic inclusions. Our experiments show that shells included in pottery fabrics are strongly influenced by the reservoir effect, which may reach 500 yr or more. Other organic inclusions, such as lake ooze, do not visibly distort the age. The obtained series of radiocarbon dates have been used for the assessing the age of the early stages of pottery manufacture in southern Russia.
22.	Adolphi, Florian, et al. (författare) Intercomparison of C-14 Dating of Wood Samples at Lund University and Eth-Zurich Ams Facilities: Extraction, Graphitization, and Measurement 2013 Ingår i: Radiocarbon. - 0033-8222. ; 55:2-3, s. 391-400 Tidskriftsartikel (refereegranskat)abstract We conducted an interlaboratory comparison between our radiocarbon-related research group at Lund University and the established ETH-Zurich facility to test the quality of the results obtained in Lund and to identify sources of potential background differences and scatter. We did find differences between the 2 laboratories in the contributions of chemical preparation, graphitization, and measurements to the overall background. The resulting overall background is, however, almost similar. Multiple measurements on 2 wood samples of known calendar age yield consistent and accurate C-14 ages in both laboratories. However, one of our known samples indicates that IntCal09 is similar to 38 +/- 16 C-14 BP too young at 7020 calendar yr BP, which is consistent with one of the raw data sets contributing to IntCal09. Overall, our results show that a systematic approach to compare the different steps involved in C-14 age determination is a useful exercise to pinpoint targets for improvement of lab routines and assess interlaboratory differences. These effects do not necessarily become apparent when comparing C-14 measurements that integrate over the whole process of preparation and measurement of different laboratories.
23.	Bronk Ramsey, Christopher, et al. (författare) Development of the Intcal Database Ingår i: Radiocarbon. - 0033-8222. Tidskriftsartikel (refereegranskat)abstract The IntCal family of radiocarbon (14C) calibration curves is based on research spanning more than three decades. The IntCal group have collated the 14C and calendar age data (mostly derived from primary publications with other types of data and meta-data) and, since 2010, made them available for other sorts of analysis through an open-access database. This has ensured transparency in terms of the data used in the construction of the ratified calibration curves. As the IntCal database expands, work is underway to facilitate best practice for new data submissions, make more of the associated metadata available in a structured form, and help those wishing to process the data with programming languages such as R, Python, and MATLAB. The data and metadata are complex because of the range of different types of archives. A restructured interface, based on the "IntChron"open-access data model, includes tools which allow the data to be plotted and compared without the need for export. The intention is to include complementary information which can be used alongside the main 14C series to provide new insights into the global carbon cycle, as well as facilitating access to the data for other research applications. Overall, this work aims to streamline the generation of new calibration curves.
24.	Eriksson Stenström, Kristina, et al. (författare) Environmental levels of radiocarbon in Lund, Sweden, prior to the start of the European Spallation Source 2022 Ingår i: Radiocarbon. - 0033-8222. ; 64:1, s. 51-56 Tidskriftsartikel (refereegranskat)abstract The European Spallation Source (ESS) is a neutron-based research facility under construction in Lund in southern Sweden. The spallation reactions will generate not only the desired neutrons, but also many radioactive byproducts, including 14C. As part of the licensing process, and as recommended by the IAEA, various preoperational studies are being carried out, including mapping the “zero-point” radiation environment around the site. As the city of Lund hosts several facilities using 14C-labeled substances, and since temporary and local 14C contamination have been observed in the past, 14C mapping is an important part of these baseline assessments. We here present a summary of 14C levels in various terrestrial environmental samples in Lund and in southern Sweden during the years 2012 to 2020. These environmental F14C do not display significantly elevated levels compared to sites located remote from Lund. We also describe a local 14C contamination event that was detected at the Lund Radiocarbon Dating Laboratory in 2009. Horse-chestnut leaves collected close to the laboratory exhibited F14C values of up to ∼25% above the clean air background. Elevated values of F14C were also found in a short tree-ring series, especially in 2007. The source of this contamination was identified and successfully removed.
25.	Fahrni, Simon M., et al. (författare) Single-Year German oak and Californian Bristlecone Pine C Data at the Beginning of the Hallstatt Plateau from 856 BC to 626 BC 2020 Ingår i: Radiocarbon. - 0033-8222. ; 62:4, s. 919-937 Tidskriftsartikel (refereegranskat)abstract As part of the ongoing effort to improve the Northern Hemisphere radiocarbon (C) calibration curve, this study investigates the period of 856 BC to 626 BC (2805-2575 yr BP) with a total of 403 single-year C measurements. In this age range, IntCal13 was constructed largely from German and Irish oak as well as Californian bristlecone pine C dates, with most samples measured with a 10-yr resolution. The new data presented here is the first atmospheric C single-year record of the older end of the Hallstatt plateau based on an absolutely dated tree-ring chronology. The data helped reveal a major solar proton event (SPE) which caused a spike in the production rate of cosmogenic radionuclides around 2610/2609 BP. This production event is thought to have reached a magnitude similar to the 774/775 AD production event but has remained undetected due to averaging effects in the decadal calibration data. The record leading up to the 2610/2609 BP event reveals a 11-yr solar cycle with varying cyclicity. Features of the new data and the benefits of higher resolution calibration are discussed.
26.	Fischer, Anders, 1951, et al. (författare) The Nekselø fish weir and marine reservoir effect in Neolithization period Denmark 2021 Ingår i: Radiocarbon. - 0033-8222. ; 63:3, s. 805-820 Tidskriftsartikel (refereegranskat)abstract The Nekselø Wickerwork provides an unusually solid estimate on the marine reservoir age in the Holocene. The basis for this result is a 5200-year-old fish weir, built of hazel wood with a brief biological age of its own. Oysters settled on this construction. They had lived only for a short number of years when the fence capsized and was covered in mud and the mollusks suffocated. Based on the difference in radiocarbon (14C) age between accelerator mass spectrometry (AMS) samples of oyster shells and wood, respectively, the marine reservoir age for this site is estimated to 273 ± 18 14C years. Re-evaluations of previously produced data from geological and archaeological sites of Holocene date in the Danish archipelago indicate marine reservoir ages in the same order as that of the Wickerwork. Consequently, we recommend the use of the new value, rather than the ca. 400 14C years hitherto favored, when correcting for the dietary induced reservoir effect in radiocarbon dates of humans and animals from the Late Mesolithic and Early Neolithic periods of this region.
27.	Fogtmann-Schulz, Alexandra, et al. (författare) Batch processing of tree-ring samples for radiocarbon analysis 2021 Ingår i: Radiocarbon. - 0033-8222. ; 63:1, s. 77-89 Tidskriftsartikel (refereegranskat)abstract We here present a comparison of methods for the pretreatment of a batch of tree rings for high-precision measurement of radiocarbon at the Aarhus AMS Centre (AARAMS), Aarhus University, Denmark. The aim was to develop an efficient and high-Throughput method able to pretreat ca. 50 samples at a time. We tested two methods for extracting α-cellulose from wood to find the most optimal for our use. One method used acetic acid, the other used HCl acid for the delignification. The testing was conducted on background 14C samples, in order to assess the effect of the different pretreatment methods on low-Activity samples. Furthermore, the extracted wood and cellulose fractions were analyzed using Fourier transform infrared (FTIR) spectroscopy, which showed a successful extraction of α-cellulose from the samples. Cellulose samples were pretreated at AARAMS, and the graphitization and radiocarbon analysis of these samples were done at both AARAMS and the radiocarbon dating laboratory at Lund University to compare the graphitization and AMS machine performance. No significant offset was found between the two sets of measurements. Based on these tests, the pretreatment of tree rings for high-precision radiocarbon analysis at AARAMS will henceforth use HCI for the delignification.
28.	Genberg, Johan, et al. (författare) Development of graphitization of μg-sized samples at Lund University 2010 Ingår i: Radiocarbon. - 0033-8222. ; 52:3, s. 1270-1276 Konferensbidrag (refereegranskat)abstract To be able to successfully measure radiocarbon with accelerator mass spectrometry (AMS) in atmospheric aerosol samples, graphitization of small sample sizes (< 50 µg carbon) must provide reproducible results. At Lund University, a graphitization line optimized for small samples has been constructed. Attention has been given to minimize the reduction reactor volume and each reactor is equipped with a very small pressure transducer that enables constant monitoring of the reaction. Samples as small as 25 µg of carbon have been successfully analyzed, and the mass detection limit of the system has probably not been reached.
29.	Genberg, Johan, et al. (författare) Sealed Glass Tube Combustion of mu g-Sized Aerosol Samples 2013 Ingår i: Radiocarbon. - 0033-8222. ; 55:2-3, s. 617-623 Tidskriftsartikel (refereegranskat)abstract It is important to evaluate each step in radiocarbon analysis to ensure that the whole process is as efficient and accurate as possible. Aerosol filter samples contain a myriad of carbonaceous compounds with varying resistance to oxidation. Complete combustion of the sample is thus of great importance to ensure that the graphitized sample is representative of the original filter sample. We have evaluated sealed tube combustion of mu g-sized aerosol samples using different types and amounts of reagents. Successful analysis of aerosol samples as small as 20 mu g C was possible following small changes to our standard on-line method. The sealed tube combustion method performs well for standard samples containing 11 mu g C.
30.	Georgiadou, Elisavet, et al. (författare) Bomb-pulse dating of human material – modelling the influence of diet 2010 Ingår i: Radiocarbon. - 0033-8222. ; 52:2, s. 800-807 Konferensbidrag (refereegranskat)abstract The atmospheric testing of nuclear weapons during the 1950s and early 1960s produced large amounts of radiocarbon. This 14C bomb pulse provides useful age information in numerous scientific fields, e.g. in geosciences and environmental sciences. Bomb-pulse dating can also be used to date human material (e.g. in forensics and medical science). Bombpulse dating relies on precise measurements of the declining 14C concentration in atmospheric carbon dioxide collected at clean-air sites. However, local variations in the 14C specific activity of air and foodstuffs occur, which are caused by natural processes as well as by various human activities. As 14C enters the human body mainly through the diet, variations of 14C concentration in foodstuffs need to be considered. The marine component of the diet is believed to be of particular importance due to the non-equilibrium in 14C specific activity between the atmosphere and aquatic reservoirs during the bomb pulse. This article reviews the 14C concentration in marine foodstuffs during the bomb-pulse era, and models how the marine component in one’s diet can affect the precision of bomb-pulse dating of human material.
31.	Georgiadou, Elisavet, et al. (författare) Potential Influence of Diet on Bomb-Pulse Dating of Human Plaque Samples 2013 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222. ; 55:2-3, s. 874-884 Tidskriftsartikel (refereegranskat)abstract The radiocarbon concentration of different atherosclerotic plaque fragments obtained from 20 patients in Portugal, operated in 2000-2001, has been measured in order to define the year of plaque formation. A difference of 1.8-15 yr was observed, with the mean and median both 9 yr, between the bomb-pulse date estimated with the CALIBomb software and the operation date. Stable isotope (delta C-13 and delta N-15) analysis was also performed and provides insight to the diet of the subjects. The wide range of measured stable isotope values could indicate that the subjects' diet varied, including an abundance of marine foodstuffs. It could also mean a different isotope fractionation process for the different plaque fragments (cap, core, interface to media) and a possible difference in tissues in which the various fragments are formed. Analysis of delta C-13 and delta N-15 values of each patient separately revealed subjects considered more influenced by marine foodstuffs consumption.
32.	Magnusson, Åsa, et al. (författare) Levels of C-14 in the terrestrial environment in the vicinity of two European nuclear power plants 2004 Ingår i: Radiocarbon. - 0033-8222. ; 46:2, s. 863-868 Tidskriftsartikel (refereegranskat)abstract Radiocarbon is produced in all types of nuclear reactors. Most of the C-14 released into the environment is in the form of gaseous emissions. Recent data on the C-14 concentration found in terrestrial samples taken in the vicinity of nuclear power plants in Romania and Lithuania are presented. We found increased C-14 levels in the surroundings of both power plants. At the Romanian power plant Cernavoda, we found excess levels of C-14 in grass within a distance of about 1000 in, the highest C-14 specific activity being 311 Bq/kg C (approximately 28% above the contemporary C-14 background) found at a distance of 200 in from the point of release (nearest sampling location). At the Lithuanian power plant Ignalina, samples of willow, pine, and spruce showed a C-14 excess of similar magnitude, while significantly higher values were found in moss samples. The samples were analyzed at the accelerator mass spectrometry facility in Lund, Sweden.
33.	Marsh, Erik J., et al. (författare) IntCal, SHCal, or a Mixed Curve? Choosing a 14C Calibration Curve for Archaeological and Paleoenvironmental Records from Tropical South America 2018 Ingår i: Radiocarbon. - 0033-8222. ; 60:3, s. 925-940 Tidskriftsartikel (refereegranskat)abstract Because the 14C calibration curves IntCal and SHCal are based on data from temperate latitudes, it remains unclear which curve is more suitable for archaeological and paleoenvironmental records from tropical South America. A review of climate dynamics reveals a significant influx of Northern Hemisphere air masses and moisture over a substantial part of the continent during the South American Summer Monsoon (SASM). Areas affected by the SASM receive unknown amounts of input from both hemispheres, where an argument could be made for either curve. Until localized tree-ring data can resolve this, we suggest using a mixed calibration curve, which accounts for inputs from both hemispheres, as a third calibration option. We present a calibration example from a crucial period of environmental and cultural change in the southern Lake Titicaca. Given our current lack of data on past14C variation in South America, our calibrations and chronologies will likely change in the future. We hope this paper spurs new research into this topic and encourages researchers to make an informed and explicit choice of which curve to use, which is particularly relevant in research on past human-environmental relationships.
34.	Muscheler, Raimund, et al. (författare) Testing and Improving the IntCal20 Calibration Curve with Independent Records 2020 Ingår i: Radiocarbon. - 0033-8222. ; 62:4, s. 1079-1094 Tidskriftsartikel (refereegranskat)abstract Connecting calendar ages to radiocarbon (C) ages, i.e. constructing a calibration curve, requires C samples that represent, or are closely connected to, atmospheric C values and that can also be independently dated. In addition to these data, there is information that can serve as independent tests of the calibration curve. For example, information from ice core radionuclide data cannot be directly incorporated into the calibration curve construction as it delivers less direct information on the C age-calendar age relationship but it can provide tests of the quality of the calibration curve. Furthermore, ice core ages on C-dated volcanic eruptions provide key information on the agreement of ice core and radiocarbon time scales. Due to their scarcity such data would have little impact if directly incorporated into the calibration curve. However, these serve as important anchor points in time for independently testing the calibration curve and/or ice-core time scales. Here we will show that such information largely supports the new IntCal20 calibration record. Furthermore, we discuss how floating tree-ring sequences on ice-core time scales agree with the new calibration curve. For the period around 40,000 years ago we discuss unresolved differences between ice core Be and C records that are possibly related to our limited understanding of carbon cycle influences on the atmospheric C concentration during the last glacial period. Finally, we review the results on the time scale comparison between the Greenland ice-core time scale (GICC05) and IntCal20 that effectively allow a direct comparison of C-dated records with the Greenland ice core data.
35.	Olsson, IU (författare) Further tests of the EDTA treatment of bones 2000 Ingår i: RADIOCARBON. - : UNIV ARIZONA DEPT GEOSCIENCES. - 0033-8222. ; 42:1, s. 49-52 Tidskriftsartikel (refereegranskat)abstract A new suite of five dares on a whale rib from Varangerfjord was completed on different fractions obtained by EDTA treatment. The intention was to test the possible influence of contaminants, the criteria for complete reactions, and the reliability of the
36.	Olsson, IU (författare) Reduction of the error multiplier by a long-term analysis of the characteristic behaviors of proportional counters 1998 Ingår i: RADIOCARBON. - : UNIV ARIZONA DEPT GEOSCIENCES. - 0033-8222. ; 40:1, s. 143-149 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract A significant reduction in cosmic-ray activity and backgrounds of the gas-filled proportional counters, as measured in a heavy iron shield, was observed when the Uppsala Conventional C-14 Laboratory was moved in 1984. The new site was better shielded from
37.	Reimer, Paula J., et al. (författare) The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0-55 cal kBP) 2020 Ingår i: Radiocarbon. - 0033-8222. ; 62:4, s. 725-757 Tidskriftsartikel (refereegranskat)abstract Radiocarbon (C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
38.	Sydoff, Marie, et al. (författare) Experiences from the production and homogeneity analysis of an AMS 14C sucrose standard for high-activity measurements 2010 Ingår i: Radiocarbon. - 0033-8222. ; 52:3, s. 1351-1357 Konferensbidrag (refereegranskat)abstract Accurate accelerator mass spectrometry (AMS) measurements rely on standards with well-known isotopic ratios. For radiocarbon measurements, a number of standards with different properties are commercially available, of which the IAEA-C6 sucrose standard with a 14C value of 150.61 pMC is the most active. When analyzing biological samples resulting from studies using 14C-labeled substances, the activity content can be up to 100 times this value. Thus, there is a need for a standard material with higher activity content than IAEA-C6 for making accurate AMS measurements on this type of sample. This paper describes the attempts of producing a standard with an activity content of about 10 times modern carbon. The material chosen has to be chemically inert, preferably non-toxic, commercially available in 14C-labeled form, and the activity must be homogeneously distributed within the material. Two different standard materials were considered: urea and sucrose. Sucrose was chosen for the new standard, since it is non-toxic, inexpensive, and organic and on combustion, forms only carbon dioxide (CO2) and water (H2O). In this paper, we discuss our experience in the production and homogeneity analysis of this material, from the crystallization of the sucrose solution to the graphitization of the samples. When using an online combustion method and a septa-sealed vial reduction method, the AMS measurements indicated that the activity was not homogeneously distributed throughout the material. Contrary to this, measurements of the sucrose solution prior to recrystallization indicated that the activity was more homogeneously distributed before than after the recrystallization. In order to determine whether the inhomogeneity depended on the graphitization method (i.e. the combustion or the reduction method) or on the material itself, 3 different graphitization methods and 2 different methods of recrystallization were tested.
39.	Wild, Eva Maria, et al. (författare) 14C-Dating of the Late Bronze Age City of Hala Sultan Tekke, Cyprus: Status Report 2019 Ingår i: Radiocarbon. - 0033-8222. ; 61:5, s. 1253-1264 Tidskriftsartikel (refereegranskat)abstract Hala Sultan Tekke is a large Bronze Age city located on the southeastern littoral of Cyprus. The city flourished from approximately 1650 BC to 1150 BC according to the archaeological evidence. Since 2010, Swedish excavations have exposed four new city quarters (CQ1–4) with three occupational phases, the 14C dating of which is of highest importance also for other contemporaneous cultures. The finds demonstrate vast intercultural connections in the Mediterranean and even with southern Scandinavia. In 2014, roughly 500 m to the east of CQ1, one of the richest cemeteries on the island was discovered. According to the archaeological evidence, the finds from the city date mainly to the 13th and 12th centuries BC. However, many of the wealthy tombs and the offering pits from the cemetery are considerably older with the oldest finds dating to the 16th century BC. This raises the question where the city quarters belonging to the oldest finds from the cemetery are situated. The radiocarbon (14C) dates from Hala Sultan Tekke have much influence on the dating of related sites because of numerous imports from a vast area. We present here new 14C data obtained in the course of the current excavations, which add to sets of already existing data.
40.	Wild, E. M., et al. (författare) C-14 DATING OF HUMIC ACIDS FROM BRONZE AND IRON AGE PLANT REMAINS FROM THE EASTERN MEDITERRANEAN 2013 Ingår i: Radiocarbon. - : Cambridge University Press (CUP). - 0033-8222. ; 55:2-3, s. 599-607 Tidskriftsartikel (refereegranskat)abstract Radiocarbon dating of plant remains is often difficult due to the complete dissolution of the samples in the alkaline step of the ABA pretreatment. At the VERA laboratory, this problem was encountered frequently when numerous Bronze and Early Iron Age samples from the eastern Mediterranean were dated in the course of the special research program SCIEM2000 and in other collaborations with archaeologists focused on that area and time period. For these samples, only a C-14 age determination of the humic acid fraction was possible. Humic acids from archaeological samples are always assessed as a second-choice material for C-14 dating. It is assumed that the C-14 ages may be affected by the presence of humic acids originating from other (younger) organic material, e. g. from soil horizons located above a sample. Therefore, when humic acids are dated a verification of the dates is crucial. To address this basic requirement, we started some time ago to date both fractions of charred seeds, wood, and charcoal samples whenever available, i. e. the residue after the ABA treatment and the humic acids extracted from the samples in the alkaline step. The results of this comparison showed that for the investigated eastern Mediterranean archaeological sites, 50 (out of 52) humic acid dates were in agreement with the C-14 dates of the respective ABA-treated samples. Statistical analysis of the age differences leads to the conclusion that the extracted humic acids originated from the samples themselves or from contemporaneous material and were not appreciably contaminated by extraneous material of different age.

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