Radiocarbon Dating: Fictitious Results with Mollusk Shells

Keith, M. L.; Anderson, G. M.

doi:10.1126/science.141.3581.634

Cited by 54 publications

(41 citation statements)

References 14 publications

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“…The D 14 C value for the intermediate fraction is merely an index of reliability for the inner fraction D 14 C as are the inner and the intermediate fraction δ 13 C values. For uncontaminated marine samples, δ 13 C must be higher than -3‰ (Keith and Anderson 1963).…”

Section: Resultsmentioning

confidence: 99%

Coastal Upwelling and Radiocarbon—Evidence for Temporal Fluctuations in Ocean Reservoir Effect off Portugal During the Holocene

Soares¹,

Dias²

2006

Radiocarbon

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ABSTRACT. This paper focuses on the use of the radiocarbon content of marine shells collected along the Portuguese coast as a proxy for the intensity of coastal upwelling off of Portugal. Differences in the 14 C ages of closely associated marine mollusk shells and terrestrial material (charcoal or bones) from several Portuguese archaeological contexts seem to be significant throughout the Holocene. ∆R values range from 940 ± 50 to -160 ± 40 14 C yr. Five of these values are significantly higher than the modern value (250 ± 25 14 C yr), while the remaining values are lower. The modern value was calculated by measuring the 14 C content of live-collected, pre-bomb marine mollusk shells. This value is in accordance with an active upwelling of strong intensity that currently occurs off of Portugal. Some primary observations based on data presented here can be made: i) during the Holocene important changes have occurred in the ocean reservoir effect off the Portuguese coast; ii) these fluctuations may be correlated with regional oceanographic changes, namely with changes in the strength of coastal upwelling; and iii) these changes suggest some sort of variability of the climatic factors forcing coastal upwelling off of Portugal.

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Section: Resultsmentioning

confidence: 99%

Coastal Upwelling and Radiocarbon—Evidence for Temporal Fluctuations in Ocean Reservoir Effect off Portugal During the Holocene

Soares¹,

Dias²

2006

Radiocarbon

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“…In contrast, the 1 4 C signal of riverine POC is significantly depleted with respect to current atmospheric values with ages reaching thousands of years, as it originates from old soil horizons, sedimentary fossil, sorbed petroleum and petroleum byproducts, and sewage sludge (Raymond and Bauer 2001). ô 1 3 C Anodonta anatina tissue values near -30%o are consistent with organic terrestrial food sources (Keith and Anderson 1963).…”

Section: Bivalve Tissue-shell14cmentioning

confidence: 86%

“…The only specimen (R-01), of Unio tumidus from a lacustrine location (Rosenfeld), presents an older tissue than shell age by over 150 yr ( (Keith and Anderson 1963;Rea and Colman 1995). Keith and Anderson (1963) hypothesized that more depleted ô 13 C values in lacustrine bivalve shells reflect the incorporation into DIC of C0 2 produced by fermentation of bottom muds that have ô 13 C values of approximately -5%o.…”

Section: R Fernandes Et Almentioning

confidence: 99%

Mussels with Meat: Bivalve Tissue-Shell Radiocarbon Age Differences and Archaeological Implications

et al. 2012

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ABSTRACT. Local reservoir ages are often estimated from the difference between the radiocarbon ages of aquatic material and associated terrestrial samples for which no reservoir effect is expected. Frequently, the selected aquatic material consists of bivalve shells that are typically well preserved in the archaeological record. For instance, large shell middens attest to the importance of mussel consumption at both coastal and inland sites. However, different physiological mechanisms associated with tissue and shell growth may result in differences in reservoir effects between the surviving component (shell) and the component relevant to dietary reservoir effects in consumers (tissue). The current study examines bivalve tissue-shell age differences both from freshwater and marine contexts close to archaeological sites where human consumption of mollusks has been attested. Results exhibited significant ,4 C age differences between bivalve tissue and shell in a freshwater context. In a marine context, no significant bivalve tissue-shell age differences were observed. The results also showed that riverine and lacustrine shells show large and variable freshwater reservoir effects. The results have important implications for establishing local reservoir effects especially in a freshwater environment. For good a priori knowledge of expected 14 C differences in organic and inorganic water, carbon is thus necessary. Furthermore, the high variability in freshwater shell 14 C ages implies the need for representative sampling from the archaeological record.

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“…Exchange of carbon isotopes has been the object of numerous studies (KEITH and ANDERSON, 1963;CHAPEL and POLACH, 1972;GRANT-TAYLOR, 1972;MANGERUD, 1972;MANGERUD and GULLIKSEN, 1975;THOM, 1972;THOMMERET, 1976;HILLAIRE-MARCEL and OCCHIETTI, 1977) and constitute an important source of error in shell age determination; the true age is increased if the exchange involves fresh water from calcareous springs or decreased -and this is the more frequent case -by the action of running water containing carbonic acid from the air. It has also been shown that the contaminations by isotopic exchanges are enhanced by the crystal structure: aragonite being far less susceptible to ionic substitution than calcite; in fact an X-Ray diffractogram is sufficient to be able to reveal tests containing recrystallized or foreign calcite.…”

Section: Methodology Of the Radiocarbon Measurementsmentioning

confidence: 99%

The Holocene transgression in the Golfe du Lion, southwestern France: Paleogeographic and paleobotanical evolution

Aloïsi

Monaco

Planchais³

et al. 2011

gpq

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Starting from multidisciplinary punctual results, the authors offer a synthesis of lithologie seismic analysis, sedimentology, palynology and radiometrical measurements from sites in sea and at the border of the Golfe du Lion. The dated samples (more than 120) and the variety of the studied sites has permitted a true methodological approach. The authors also propose a curve of the rising of the Holocene sea that takes into account two major facts: the géomorphologie localisation of the site and the characteristics of the sedimentary environment (sedimentary facies and paleobotanic environment). They conclude to: 1) a generalised rapid rise of the transgression since 14,000 years BP, with an acceleration from 8000 to 6000 years BP; 2) intervals of relative stability from 12 000 to 8 000 years BP; 3) a high sea-level at +2 m at around 4500 years BP.

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Radiocarbon Dating: Fictitious Results with Mollusk Shells

Cited by 54 publications

References 14 publications

Coastal Upwelling and Radiocarbon—Evidence for Temporal Fluctuations in Ocean Reservoir Effect off Portugal During the Holocene

Coastal Upwelling and Radiocarbon—Evidence for Temporal Fluctuations in Ocean Reservoir Effect off Portugal During the Holocene

Mussels with Meat: Bivalve Tissue-Shell Radiocarbon Age Differences and Archaeological Implications

The Holocene transgression in the Golfe du Lion, southwestern France: Paleogeographic and paleobotanical evolution

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