Variability in North Atlantic marine radiocarbon reservoir effects at c. AD 1000

Ascough, Philippa; Cook, Gordon; Church, Mike J.; Dugmore, Andrew; Arge, Símun V.; McGovern, Thomas H.

doi:10.1191/0959683606hl913rr

Cited by 40 publications

(46 citation statements)

References 36 publications

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“…Publishing the mean value from R calculations for each context is commonplace (Reimer et al 2002;Ascough et al 2004Ascough et al , 2005Ascough et al , 2006Ascough et al , 2007Ascough et al , 2007aAscough et al , 2009Weisler et al 2009;Soares and Martins 2010) and provides a concise method of presenting the values. However, in order to understand the true spread of values as a more appropriate measure of variability, a useful method is to employ a histogram to display the variability in R values derived from multiple pairs of terrestrial and marine samples (i.e.…”

Section: New Methodsmentioning

confidence: 99%

Examining the Inherent Variability in ΔR: New Methods of Presenting ΔR Values and Implications for MRE Studies

et al. 2011

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ABSTRACT. Currently, there is significant ongoing research into the temporal and spatial variability of marine radiocarbon reservoir effects (MREs) through quantification of R values. In turn, MRE studies often use large changes in R values as proxies for changes in ocean circulation. R values are published in a variety of formats with variations in how the errors on these values are calculated, making it difficult to identify trends or to compare values, unless the method of calculating the R is explicitly described or all of the data are made available in the publication. This paper demonstrates the large range in R values (+34 to -122) that can be obtained from a single, secure archaeological context when using the multiple paired sample approach, despite the fact that the terrestrial entities were of statistically indistinguishable 14 C ages, as were the marine samples. This demonstrates the inherent variability in the R calculations themselves and we propose that, together with calculation of mean R, the distribution of R values should be displayed, e.g. as histograms in order to illustrate the full data range. This spread is only apparent when employing a multiple paired sample approach as the uncertainty derived on a single pair of samples, taking account only of the errors on the individual 14 C ages, will never truly represent the overall variability in R that results from the intrinsic variability in the population of 14 C ages in samples that might have been used. Consequently, R values and the associated uncertainty calculated from single pairs should be treated with some caution. We propose that, where possible, when using paired archaeological samples, that a multiple paired approach should be employed as it will test the context security of the material used in the R calculations. When summarizing the values by the weighted average, we also propose that the standard error for predicted values should be employed as this will fully encompass the uncertainty of a future R calculation, using different samples for a similar time and location. Finally, we encourage future publishing of R values using the histogram format, making all of the data available. This will help ensure that R values are comparable across the literature and should provide a framework for standardization of publication methods.

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Section: New Methodsmentioning

confidence: 99%

Examining the Inherent Variability in ΔR: New Methods of Presenting ΔR Values and Implications for MRE Studies

et al. 2011

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“…When Scandinavian settlers arrived, they encountered a mid-Atlantic island with substantial arctic birch forest in the lower elevations, coastal sea mammal (including walrus) and sea bird colonies, migratory nesting birds, and the green grass that could feed their imported domestic livestock. The economy of the Viking Age North Atlantic settlers was flexible but based around stock raising supplemented by limited barley growing and often extensive use of wild species (Dugmore et al 2005;McGovern et al 2001;McGovern et al 2006;Simpson et al 2002). Pasture was the ultimate source of wealth and power, and the correlation of cattle, good grazing, and chieftainship is clear in both the historical and archaeological record Vésteinsson 1998).…”

Section: Case Study: Early Settlement In North Icelandmentioning

confidence: 99%

Landscapes of Settlement in Northern Iceland: Historical Ecology of Human Impact and Climate Fluctuation on the Millennial Scale

McGovern

Vésteinsson

FRI?RIKSSON³

et al. 2007

American Anthropologist

168

123

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Citation for published item:wqovernD F rF nd ¡ esteinssonD yF nd pririkssonD eF nd ghurhD wF tF nd vwsonD sF F nd impsonD sF eF nd iinrssonD eF nd hugmoreD eF tF nd gookD qF F nd erdikrisD F nd idwrdsD uF tF nd homsonD eF wF nd edderleyD F F nd xewtonD eF tF nd vusD qF nd idvrdssonD F nd eldredD yF nd hunrD iF @PHHUA 9vndspes of settlement in northern selnd X historil eology of humn impt nd limte )utution on the millennil sleF9D emerin nthropologistFD IHW @IAF ppF PUESIF Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. T H O M A S H . M c G O V E R N , O R R I VÉ S T E I N S S O N , A D O L F F R I -D R I K S S O N , M I K E C H U R C H , I A N L AW S O N , I A N A . S I M P S O N , A R N I E I N A R S S

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“…De modo geral, átomos de 14 C precisam viajar distâncias consideráveis para atingir as profundezas do enorme reservatório marinho e, dessa forma, os tempos de residência são muito maiores que na atmosfera (Sigman & Boyle 2000). Durante esse tempo, esses átomos podem decair, diminuindo a atividade de 14 C do oceano profundo (Ascough et al 2004(Ascough et al , 2006. Além disso, a dissolução de carbonatos antigos contribui para diminuir ainda mais a concentração de 14 C no ambiente marinho e fatores como a ressurgência atenuam a atividade do oceano superficial (Ascough et al 2004(Ascough et al , 2006.…”

Section: Radiocarbono No Ambiente Marinhounclassified

“…Durante esse tempo, esses átomos podem decair, diminuindo a atividade de 14 C do oceano profundo (Ascough et al 2004(Ascough et al , 2006. Além disso, a dissolução de carbonatos antigos contribui para diminuir ainda mais a concentração de 14 C no ambiente marinho e fatores como a ressurgência atenuam a atividade do oceano superficial (Ascough et al 2004(Ascough et al , 2006. Dessa forma, o reservatório oceânico é pobre em carbono 14 se comparado com a atmosfera e esse fenômeno recebe o nome de efeito de reservatório marinho (Stuiver et al 1986, Stuiver & Braziunas 1993, Ascough et al 2004.…”

Section: Radiocarbono No Ambiente Marinhounclassified

Efeito de reservatório marinho na costa do Brasil

Macario

Alves

2018

ABEQUA

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ResumoEm estudos cronológicos de processos ocorridos nos últimos 50 mil anos, a datação de carbono 14 é a abordagem mais utilizada em todo o mundo. Para permitir a correta interpretação das idades obtidas, faz-se necessária a calibração dos resultados com base em um robusto banco de dados produzido pela comunidade científica na área de radiocarbono. A calibração objetiva, principalmente, considerar as variações na produção e distribuição do 14 C ao longo do tempo e, no caso do ambiente marinho, corrigir ainda que parcialmente o Efeito de Reservatório Marinho (Marine Reservoir Effect -MRE). De fato, dado que a magnitude do fenômeno aumenta com a profundidade e varia espacialmente em função da dinâmica oceânica, a simples calibração com uma curva marinha global é incapaz de lidar com a real variabilidade do efeito, rendendo resultados não acurados. Desse modo, considera-se também uma correção local, denominada ∆R, com valores disponíveis na literatura para diversas regiões do globo. Assim, no procedimento que é atualmente o padrão adotado em estudos cronológicos, a correção local para o MRE antecede a calibração de uma idade de 14 C marinha com a curva global. Aqui objetivamos elencar os valores de ∆R disponíveis para a costa brasileira, mostrando o impacto causado na calibração das idades de radiocarbono e a importância desse tipo de correção para estudos cronológicos baseados na datação de 14 C de material marinho. Discutimos, finalmente, os problemas causados pela falta ou pelo uso equivocado dessa correção. Palavras-chave: radiocarbono; calibração; amostras marinhas; datação AbstractFor chronological studies encompassing periods within the last 50 thousand years, carbon 14 dating is the most used approach. Calibration with a robust data set allows the correct interpretation of obtained ages by considering temporal variations in radiocarbon production and distribution. In the case of marine radiocarbon ages, calibration is also meant to correct for the so-called Marine Reservoir Effect (MRE). Since the magnitude of this phenomenon increases with depth and varies spatially due to ocean dynamics, simple calibration with a global marine curve is incapable of dealing with the real variability of the effect, yielding inaccurate results. Therefore, one must also consider local corrections, termed ∆R, available in the literature for different regions of the globe. Currently, applying local corrections to marine radiocarbon ages prior to calibration with the most recent global marine curve is a standard practice in chronological studies. Here we aim to list available ∆R values for the coast of Brazil, showing their impact on the calibration of radiocarbon ages and the importance of such correction for chronological studies based on the 14 C dating of marine material. Problems arising from the misuse of ∆R values and/or lack of MRE corrections are also discussed.

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Variability in North Atlantic marine radiocarbon reservoir effects at c. AD 1000

Cited by 40 publications

References 36 publications

Examining the Inherent Variability in ΔR: New Methods of Presenting ΔR Values and Implications for MRE Studies

Examining the Inherent Variability in ΔR: New Methods of Presenting ΔR Values and Implications for MRE Studies

Landscapes of Settlement in Northern Iceland: Historical Ecology of Human Impact and Climate Fluctuation on the Millennial Scale

Efeito de reservatório marinho na costa do Brasil

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