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- Dury, Jack, 1993-
(författare)
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Dealing With Reservoir Effects in Human and Faunal Skeletal Remains : Understanding the radiocarbon dating of aquatic samples
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Archaeology relies on the ordering of past events to study cultural developments. This has traditionally been achieved by looking at the stratigraphic depths of materials relative to one another. In this way, chronologies of past technological progressions and stylistic changes can be built. The introduction of radiocarbon dating in the 1950s revolutionised archaeology, allowing for direct, numerical estimates of a sample’s age. This allowed for more detailed past chronologies than was previously possible. Radiocarbon dating utilises the radioactive decay of carbon-14 (radiocarbon, 14C) to estimate a sample’s age with older samples having less 14C. Shortly after the introduction of radiocarbon dating, however, it was demonstrated that 14C is not evenly distributed globally. Typically, there is less 14C in marine (and sometimes freshwater) systems compared to the atmosphere. This results in aquatic samples appearing older than they are, a phenomenon known as a ‘reservoir effect’. When radiocarbon dating material from archaeological sites with marine activity, this is an important consideration. With aquatic resources being vital for human populations across the globe and for millennia, the ability to interpret aquatic radiocarbon dates is incredibly important. Making use of radiocarbon dates without properly handling any reservoir effects have proved problematic, sometimes resulting in archaeologically incorrect chronologies being constructed. Reservoir effects can, however, be managed. This thesis demonstrates how archaeologists should interpret radiocarbon dates from aquatic samples, avoiding erroneously-old age estimates. Through careful sample selection, considering complicated carbon source mixing, measuring the scale and variability of reservoir effects within a single ecosystem and using prior knowledge about a sample’s age, the dating of aquatic material can be greatly improved. This thesis also details a novel method of dating teeth, reducing uncertainty, and concomitantly estimating the extent of the reservoir effect. This was achieved by dating dental increments, combined with complex modelling. It is clear that there is no single method of handling reservoir effects, and methods for dealing with reservoir effects will differ depending on the archaeological site and specific research question. In this thesis, novel and existing methods of dealing with reservoir effects are demonstrated by considering five case studies from four archaeological sites:At the site of Hamanaka 2 (Rebun Island, Japan), it is demonstrated that by carefully selecting samples without reservoir effects, the dating of the stratigraphy of the site can be accurately modelled. Concerning the cemetery site of Rounala (northern Sweden), it is demonstrated that by carefully reconstructing complex human diets, the dating of humans can be modelled to a high resolution. This has implications for the understanding of the Church’s relationship with the cemetery. At the site of Ekven (Chukotka, Bering Strait) reservoir effect variability between species is carefully described. A more detailed understanding of regional reservoir effects allows for more accurate dating of human remains from the marine hunting Old Bering Sea culture. More accurate dating of human remains allows for the refining of existing Old Bering Sea culture chronologies. Finally, concerning the material from Resmo (Ӧland, Sweden), a novel dental wiggle matching model is presented as a possible method for reducing dating uncertainty in individuals with a marine dietary component.
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- Dury, Jack, et al.
(författare)
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Dental wiggle matching : Radiocarbon modelling of micro-sampled archaeological human dentine
- 2021
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 595, s. 118-127
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Tidskriftsartikel (refereegranskat)abstract
- Marine reservoir effects (MRE) have the potential to increase the dating uncertainty of humans incorporating marine resources into their diets. Here we attempt a novel dental wiggle-match model to reduce dating uncertainty of seven individuals from the Resmo megalithic tomb (Öland, Sweden) and to test whether this model can be used to calculate MRE from a single tooth. Previous stable isotope ratio studies of these individuals demonstrated that their diets changed, between more or less marine protein, during the early years of their lives. Several incremental samples of dentine from each individual were subjected to radiocarbon dating and stable isotope ratio analysis. An OxCal model was designed that makes use of the known formation sequence of human teeth to reduce overall dating uncertainty. The new dental wiggle-match model is able to reduce overall dating uncertainty in all of the sampled individuals compared to more conventional 14C calibration methods. A utility of the dental wiggle model to estimate marine reservoir effects without associated faunal material is also demonstrated, with promising results.
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- Dury, Jack P. R., et al.
(författare)
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CONSIDERATION OF FRESHWATER AND MULTIPLE MARINE RESERVOIR EFFECTS : DATING OF INDIVIDUALS WITH MIXED DIETS FROM NORTHERN SWEDEN
- 2018
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Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 60:5, s. 1561-1585
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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.
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- Dury, Jack, et al.
(författare)
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Species-specific reservoir effect estimates : A case study of archaeological marine samples from the Bering Strait
- 2022
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 32:11, s. 1209-1221
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Tidskriftsartikel (refereegranskat)abstract
- Due to the marine reservoir effect, radiocarbon dates of marine samples require a correction. Marine reservoir effects, however, may vary among different marine species within a given body of water. Factors such as diet, feeding depth and migratory behaviour all affect the 14C date of a marine organism. Moreover, there is often significant variation within single marine species. Whilst the careful consideration of the ΔR values of a single marine species in a given location is important, so too is the full range of ΔR values within an ecosystem. This paper illustrates this point, using a sample pairing method to estimate the reservoir effects in 17 marine samples, of eight different species, from the archaeological site of Ekven (Eastern Chukotka, Siberia). An OxCal model is used to assess the strength of these estimates. The marine reservoir effects of samples passing the model range from ΔR (Marine20) = 136 ± 41–ΔR = 460 ± 40. Marine reservoir effect estimates of these samples and other published samples are used to explore variability in the wider Bering Strait region. The archaeological implications of this variability are also discussed. The calibrating of 14C dates from human bone collagen, for example, could be improved by applying a dietary relevant marine reservoir effect correction. For humans from the site of Ekven, a ΔR (Marine20) correction of 289 ± 124 years or reservoir age correction of 842 ± 123 years is suggested.
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- Junno, Ari, et al.
(författare)
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Building a high-resolution chronology for northern Hokkaido - A case study of the Late Holocene Hamanaka 2 site on Rebun Island, Hokkaido (Japan)
- 2021
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 2352-409X .- 2352-4103. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Archaeological radiocarbon dating in coastal northern Hokkaido is challenged by the marine reservoir effect and the scarcity of materials with terrestrial carbon sources. This has contributed to gaps and general uncertainty in the timing of the region's culture-historical periods. The Late Holocene site of Hamanaka 2 on Rebun Island, featuring a stratified shell midden context with excellent preservation of organic remains, provides an ideal setting for addressing this issue. A Bayesian chronological model was deployed to study the timing of the site using a series of radiocarbon-dated macrobotanical samples. This resulted in narrowed-down estimated ageranges in eight of thirteen phases examined, providing the site with a more accurate radiocarbon chronology than before. These temporal data were consequently integrated with local palaeoecological evidence, revealing synchrony between cultural chronology and human-induced landscape transformations. The study demonstrates that the technique should permit more efficient building of archaeological chronologies in similar maritime environments.
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- Larsson, Anton, 1994-, et al.
(författare)
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Jordfallet at Bohus : Reinterpreting the 14C dating of a medieval landslide event
- 2022
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Ingår i: Radiocarbon. - 0033-8222 .- 1945-5755. ; 64:5, s. 1239-1255
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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.
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