Intrashell Radiocarbon Variability in Marine Mollusks

Culleton, Brendan J.; Kennett, Douglas J.; Ingram, B. Lynn; Erlandson, Jon M.; Southon, John

doi:10.1017/s0033822200038820

Cited by 93 publications

(100 citation statements)

References 62 publications

(102 reference statements)

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“…From each of these shells, we removed a 5-mm cross-section perpendicular to the edge across multiple increments of growth to avoid intrashell variations in 14 C (cf. Culleton et al 2006) and provide an average value over a maximum period of 5 yr (i.e. 1 increment in the Marine04 data set).…”

Section: Methodsmentioning

confidence: 99%

New Marine ΔR Values for the South Pacific Subtropical Gyre Region

et al. 2008

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ABSTRACT. This paper presents 31 new ΔR results of known-age, pre-AD 1950 shells from the South Pacific subtropical gyre region, spanning from the Tuamotu Archipelago in the east to New Caledonia in the west. This doubles the number of available ΔR values for the Oceania region. These values indicate that the regional offset (ΔR) from the modeled radiocarbon marine age has remained relatively constant over the last 100 yr prior to 1950. Variation from the norm can be attributed to various influences including localized upwelling around islands, the presence of a hardwater effect, direct ingestion of old carbon by the live shellfish, or enhanced exchange with atmospheric CO 2 as a consequence of photosynthetic activity or increased aeration.

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Section: Methodsmentioning

confidence: 99%

New Marine ΔR Values for the South Pacific Subtropical Gyre Region

et al. 2008

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“…Small fluctuations in the Kilen reservoir age might be result of these variations. However, this is more likely to happen in regions with variations in the upwelling of deep-sea water [95,99,100].…”

Section: Sediment Core Samples From the Limfjordmentioning

confidence: 99%

The freshwater reservoir effect in radiocarbon dating

2013

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The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known as hard water, is the most common reason for the freshwater reservoir effect. It is therefore also called hardwater effect. Although it has been known for more than 60 years, it is still less well-recognized by archaeologists than the marine reservoir effect. The aim of this study is to examine the order of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14 C years can occur within one river. The freshwater reservoir effect has also implications for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany. The surprisingly old ages of the earliest pottery most probably are caused by a freshwater reservoir effect. In a sediment core from the Limfjord, northern Denmark, the impact of the freshwater reservoir effect on radiocarbon dating in an estuarine environment is examined. Here, freshwater influence causes reservoir ages to vary between 250 and 700 14 C years during the period 5400 BC -AD 700. The examples in this study show clearly that the freshwater reservoir effect can seriously corrupt radiocarbon dating at inland sites. Reservoir effects should therefore be considered whenever food remains on pottery or the bones of omnivores are radiocarbon dated -irrespective of the site's distance to the coast.

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“…For one thing, the sequential, high-precision dating of this single Mercenaria valve makes it crystal clear that the marine reservoir surrounding St. Catherines Island is extraordinarily stable on a season-to-season basis. This portion of the Georgia Bight is totally lacking in the radical fluctuations within the annual cycle caused by varying supplies of old carbon resulting from upwelling, as noted elsewhere in the world (e.g., Kennett et al, 1997;Culleton et al, 2006). We have previously assumed this to be true, but this is the first empirical evidence that effectively tests this important assumption.…”

Section: Potential Issues Of Oceanic Upwellingmentioning

confidence: 91%