Marine Reservoir Variation in the Bismarck Region: An Evaluation of Spatial and Temporal Change in ΔR andROver the Last 3000 Years

Abstract

ABSTRACT. Interactions between islands, ocean currents, and winds cause large-scale eddies and upwelling in the lee of islands that can result in spatial variation in the marine radiocarbon reservoir. For waters around New Ireland and the Bismarck Sea, R values ranging from 365 to -320 14 C yr have been reported (Kirch 2001;Petchey et al. 2004). Petchey et al. (2004) proposed that some of this variation was caused by seasonal reversals in the South Equatorial Current and North Equatorial Counter Current system, combined with Ekman upwelling from the Equator. McGregor et al. (2008) suggested additional complexity within this region caused by a change in the reservoir value over time in response to changing climatic conditions. We present a series of 14 new and extant published R and R values on historic shells, combined with 8 values from archaeological terrestrial/marine pairs and U-Th dated coral, that support observations of localized variability caused by a complex interplay between seasonal currents, riverine input, and ocean eddies. On the basis of these values and oceanographic data, we divide the Bismarck Sea surface marine 14 C reservoir into 6 tentative subregions. In particular, our results support significant variation within channels at the southwest and southeast ends of New Britain and towards the equatorial boundary of the sea. Our results indicate that within the Bismarck Sea geographical variation appears to be more extreme than temporal over the last 3000 yr.

The first farmers in Cantabrian Spain: Contribution of numerical chronology to understand an historical process

“…The most common example is the 'old-wood effect' where charcoal from the center of a trunk is dated, but numerous other examples also exist. For example, marine mollusks grazing on a limestone substrate may have a significant inbuilt age that cannot be accounted for using a marine reservoir correction (DR) (Petchey and Ulm, 2012). This second criterion has only been applied to radiocarbon dates.…”

The freshwater reservoir effect in radiocarbon dating

“…In other studies, though, an influence of the habitat and diet of shellfish on the reservoir age has been observed (e.g. [95]). During inferred marine conditions, it can be expected that the Kilen reservoir age R is c. 400 years ( R ≈ 0).…”

“…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].…”

Decadally Resolved Lateglacial Radiocarbon Evidence from New Zealand Kauri

“…This contrasts with Papua New Guinea (PNG) data ( Figure 10A; Edwards et al 1993, which are 150 -320 14 C yr too young for the interval 14,180 -10,670 cal BP. Reservoir age discrepancies in the PNG records are likely caused by the complex interplay of ocean currents encircling PNG, as indicated by marine shell/identified charcoal paired dates and pre-1950 shell dates derived from archaeological sites, with R values for the Huon Peninsula ranging from 71 ± 51 yr to 611 ± 16 yr (Petchey and Ulm 2012). The large range of R values for PNG have resulted in a large error term for ages used in IntCal13 (R = 495 ± 155), with the R errors propagated with the 14 C date measurement errors.…”